Trees with Shallow Roots

Getting ready for fall planting trees? Near a deck, patio or pathway? Here are some general guidelines to allow for adequate space root growth: (All info. from: Roots Demystified, change your gardening habits to help roots thrive.)

- It’s best not to plant trees between paved areas with less than three feet of soil to grow.

- Use trees that mature at less than 30 feet tall when you have a space with three- to four-feet between paved areas, such as between a sidewalk and the street next to a patio or foundation.

-If you’re lucky enough to have a space of five to six feet between paved areas, you can plant trees that mature as high as 50 feet tall.
With trees higher than 50 feet you’ll need at least eight feet between paved areas.
[in the March 31, 1995 issue, p. 36. Prepared by Sherry Rindels, Department of Horticulture Iowa State University, Ames, Iowa. ]

Trees Incompatible With Paved Areas:
Common Name, Latin Name, Cultivar, Zones, Size (H’/W)’.
Red Maple, Acer rubrum ‘Franksred’. Zones 3-9, 45’x 35’.
Sugar Maple Acer saccharum. Zones 3-8, 70’x 45’. (Pictured here.)
European Beech, Fagus sylvatic. Zones (4)5-7, 55’ x 40’.
White Ash, Fraxinus americana. Zones 3-9, 60’x 60’.
Tuliptree, Liriodendron tulipifera. Zones 4-9, 80’x40’.
Sweetgum, Liquidambar styraciflua. Zones 5-9, 70’x 45’.
Southern Magnolia, Magnolia grandiflora Zones 6-9, 60’x 50’.
London Planetree, Platanus x acerifolia. Zones 4-8(9), 80’x 70’.
American Sycamore, Platanus occidentalis. Zones 4-9, 80’x 80’.
Poplars, Populus nigra. Zones 3-9, 80’x 12’.

Grape Roots

These grape roots reveal a lot about root growth in naturally shallow soils. The roots here are all in the top two feet of the soil.

Roots find conditions the most cushy and convenient near the surface of the soil and will do almost anything to live there. Since they can’t find their way through hardpan or less fertile soil, it can be quite deep and there’s no real reason to try to break it up. If the drainage is poor and water is likely to flood the roots, and if there is some decent soil beneath the hardpan, then breaking through will probably be required. With this grape vineyard the soil is shallow and clay is like a hardpan just a few feet below the surface. Notice how large the diameter of the surface roots are. The roots haven’t been able to piece the clay to get to the lens (pocket) of gravel and sand much deeper in the soil.

Based on my book, Roots Demystified, Change Your Gardening Habits to Help Roots Thrive.


“BUY FROM THE SOURCE TO HELP KEEP WRITERS WRITING”


Let me know what you think. Visit my web site to learn about my new book on drip irrigation and other gardening books. Thanks, Robert

Basket Bondage?

It’s spring in full-tilt boogie. Where there are gophers, the trend has been to plant in wire baskets. In the past ½-inch aviary wire was used. While fairly easy to work with, it doesn’t last a long hardware cloth with regards to rust. There are some pre-made commercial wire baskets. They aren’t very deep, but the wire is studier than aviary wire.

The fear is what happens to the roots that grow thru the wire. As illustrated in my blog of 5/10/10, many roots are eaten at the wire’s edges. This makes the plant more like a container plant with the roots feeding only within the wire basket. Those that do manage to escape the cruddy teeth of the western pocket gopher have to deal with growing in and thru the wire.

The question is as the roots that grow thru the basket, as shown on the left, get harmed and is growth reduced? Wire can be included within the tissues of growing plants without apparent harm. The other photograph shows how an oak tree is slowly swallowing a 4” X 4” sign post.

In my experience a plum tree planted in a very shallow wire basket was greatly stunted. It failed to produce the thicket of long spindly shoots each summer. With all the other trees planted within 4’ deep & 3’ wide baskets, seems the trees a perfectly happy. They are the Asian pear, plum, plumcot, apple, and persimmon trees.

So it seems wire is simple swallowed up by the basket and the transport of water & nutrients up-and-down the tree remains relatively unharmed.



“BUY FROM THE SOURCE TO HELP KEEP WRITERS WRITING”


Let me know what you think. Visit my web site to learn about my new book on drip irrigation and other gardening books. Thanks, Robert

Concrete Kills

In my book Roots Demystified, Change Your Gardening Habits to Help Roots Thrive I talk about how important it is to allow the soil to breath for the best growth of roots. Roots with compaction or hardscape don't thrive. Here's a large, formerly beautiful, oak tree surrounded by a parking lot, driveway, sidewalk, and street. As the butchered pruning shows, the tree is rapidly dying over the past five years - a short period of time for an oak tree that can last for several hundred years or more. Such a glorious tree slowly dieing due to an anaerobic form of root bondage.

“BUY FROM THE SOURCE TO HELP KEEP WRITERS WRITING”


Let me know what you think.Visit my web site to learn about my new book on drip irrigation and other gardening books.NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Mounds, not the candy

I like to plant trees and shrubs on constructed
soil mounds as opposed to planting them in
flat ground. If you’re working with slightly
heavy clay/loam soils, the mounding is
especially critical to preventing root or crown
rot (Phytophthora spp.—a fungal disease of the
upper portion of the roots, near the soil surface).
Many ornamental and fruiting tree and shrubs die
of crown rot without the gardener ever suspecting
the culprit. The fungus damages the sapwood,
either killing individual limbs or the entire plant.
Once the symptoms (pale-yellow, wilted leaves)
appear, it’s too late to do anything about it.

So, mounds help stave off root rot.

In areas where the summers are dry, make your
planting mounds in the fall; then all you have
to do in early spring after bare root roses, fruiting
and ornamental trees, and berries arrive is open
the winter wet soil enough to place the roots and
cover it with native soil. In areas where it rains in
the summer, wait until the soil drains after a rain
so that it’s moist, not wet.

Here you can see the cross section of a mound made
of composting chips and leaves from a tree service.
The mound is capped with six to ten inches of soil and immediately
planted. All plants are still planted on small mounds on the composting mound.

Based on my book Roots Demystified.

Visit my web site to learn about my new book on drip irrigation and other gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Error in Paris

Last year I traveled to Paris. In one of the oldest parks in Paris was one of the oldest Sycamore trees in the city. This sign shows that all that history and current science has got it wrong about root growth. They need to read my book Roots Demystified. If they read it, they would understand that all tree roots are at least 1/2 times wider than the canopy (dripline). In a sandy soil the roots can grow three to seven times wider than the dripline.

I think the last paragraph talks about the root system and nutrients, but I can not read French. Maybe someone reading this blog could translate it for me and others. (Click on the image to get a full screen view to make it easier to read.)

Visit my web site to learn about my new book on drip irrigation and other gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Root Bondage

Here’ a view from above of what’s left of an apple tree’s roots growing in a wire basket.

Wire baskets around here are becoming required planting additions for perennials, shrubs, and trees. I once had a wire basket protecting the apple tree in the photo. The wire was four inches above the mulch. That didn’t stop a gopher from climbing over the wire to be encaged with all those succulent roots. The tree leaned over and simply died.

As the photo shows [I’m the only person I know of that has excavated the roots as they grow when using wire baskets] very few of the roots got out of the basket to explore a bigger volume of soil. For practical purposes, this tree should have been treated like a container plant—keeping all the moisture, fertility, and mulch within the basket’s diameter. BUT, the wire must extend 6-12 inches above the mulch to have a shot at excluding these pesty critters. Such a wire basket is very hard to make and isn’t to be found commercially. Your up to your own to make a Rube Goldberg machine-made, anti-gopher basket .

However, wire baskets can work with smaller plants.

Please post a comment - I want to know what you think.

Visit my web site to learn about my new book on drip irrigation and other gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Ramblin' Roots

Sadly, few people still realize how a tree's roots actually grow. The color illustration was to advertise a local garden tour in 2009. Notice the roots don't extend beyond the dripline of the foliage. No way. As seen in the illustrations below roots extend far beyond the foliage. (The other 2 B&W illustrations come from my book - Roots Demystified. The one on the left shows the dripline as a dotted line and the roots beyond..)

When I had a landscape maintenance company, I soon discovered that in a good soil, a tree’s roots will often grow to occupy an underground area wider than its dripline. If led by available moisture and nutrition, a tree may tunnel its roots through soil space ranging from an area one-half wider than the dripline to as much as three times further. In special cases, tree roots may ramify much more than anyone would imagine. If you add a subsoil barrier such as rock, bedrock, or caliche (hardpan), a tree’s roots will wander even further beyond the canopy area in search of food. A deep sandy soil offers little resistance to growing roots and allows for root exploration of three or more times the width of the tree. And, like a gardener struggling to dig heavy clay soil, roots don’t like clay either and don’t make much headway through it, perhaps only one-half the width of the dripline.

Some more examples include:

- Poplar (Populus generosa) can ramify 77% of its roots beyond the dripline.

- Another study found that 35% of poplar trees grew roots greater than two times the distance from the trunk to the edge of the foliage.

- Colorado blue spruce (Picea pungens ‘Glauca’) grow 60% of their feeding roots beyond the dripline.

- White green ash (Fraxinus pennsylvanica) grew roots which were 1.68 times the radius of the dripline.

- In one study, the glorious magnolia (Magnolia grandiflora), had grown roots 3.77 times wider than the dripline.

- Sugar maples (Acer saccharum) produced roots that have been found spreading underground 30 feet beyond branch tips.

- The roots of honey locusts (Gleditsia triacanthos) can reach nearly three times beyond the dripline of the foliage.

Please post a comment - I want to know what you think.

Visit my web site to learn about my new book on drip irrigation and other gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Don't let roots circle when planting trees & shrubs

Spring is tree-planting time for many gardeners. It's also the time to make big mistakes when planting. Alas, this tree popped out of it's planting hole due to poorly-trained landscape contractors after being struck by a car. This poor tree needed to get its roots away from the planting hole. (You can see the circling roots just the way they were in the planting container.) Planting on a mound will help "drive" roots away from the tree's base as it drys out faster, making the roots seek moisture further from the trunk. So will fracturing the sides of the hole. (This tree may have been "planted" by auguring a hole in the ground and just plopping the tree into the hole.) The roots responsible for absorbing water and nutrients are the very young and tiny root hairs found near the tips of new roots. Older roots, much like older branches, have a bark-like covering that protects the root but doesn’t produce root hairs. In one study done with radioactive isotopes in England, the roots 4.5 feet away from the trunk of a 10-year-old apple tree absorbed less than 10% of the water and nutrients absorbed by the entire root system. The study showed that proportionately, many more feeding roots are found at, or beyond, the drip line of a tree’s foliage. Because of this, I prefer to place a ring of in-line emitter tubing at or beyond the tree’s drip line. This produces a “doughnut” of moisture, and far more of the root zone is adequately irrigated than with a single line of hose down a row of trees. As the tree grows, extra lengths are added to this circle of moisture to correspond with the new growth in the canopy. By setting the circle of emitters farther out every few years, you’re encouraging the tree’s roots to explore more soil volume and gather more nutrients for superior growth. Such trees would stand a better chance against wayward cars.

Note: I somehow lost the usual section "Post a comment". To leave a comment, simply click on the area/button that says "___ Comments" below. Or, clicking on the title of a Post under "Blog Archive" also gets you to a view that gives the option of leaving a comment. Robert

Visit Robert Kourik's web site to learn about his great gardening books.

The Myth of the Range of Tree Roots

The following is text from my book: Roots Demystified, Change Your Garden Habits to Help Roots Thrive.

The best book on the topic of fruit tree roots is The Root System of Fruit Plants compiled by a Russian named V. A. Kolesnikov. (As with most scientific papers, only initials are used for all but the surname.) Kolesnikov’s scientific papers appeared from 1924 until 1968, indicating that the USSR regime certainly valued his distinctive research.

Kolesnikov’s primary modus operandi for studying roots was the one he called “The Skeleton Method.” As with Professor Weaver’s studies, this method entailed precise excavation of the roots. In imitation of archaeological techniques, shovels were used first, followed by scoops and, eventually, brushes. This approach preserved more fine root hairs during excavation than the most common practice of using water forced from a hose, or even more than simple washing of the roots.

Kolesnikov’s conclusion is that fruit tree roots grow one-and-one-half to two and even three times the width of the foliage above them. More amazingly, he states that this ratio is maintained throughout the life of the tree, regardless of the rootstock, species, and soil (my emphasis added). This is clearly seen in the apple tree illustration depicted in the left side above. (Click on the image to get a better view.) Each type of fruit tree maintains a slightly different ratio of root mass to canopy. The best place for water, fertilizer, compost, and mulch is beyond the foliar dripline (canopy). This applies to most trees, not just fruit trees. The roots of fruit trees are studied more than ornamental or native trees because they are economic crops.

The illustration on the right is the misguided imagination of a graphic artist. Pretty to look at, but dead wrong. The roots in no way mirror the above-ground foliage.

The relationship of the width of a tree’s root-mass to the amount of moisture it should receive is critical. Applying water near the trunk is wasteful in any climate. In a climate that routinely experiences short droughts of a month or so up to six months (as in parts of the Southwest), drip irrigation is the most efficient way to distribute water to an entire root system.

The climate, however, need not be arid for trees to benefit from drip irrigation. In a study of established pecan trees in humid Georgia, trees with added drip irrigation showed a 51% increase in yields.

It's nuts to irrigate any other way.

Please post a comment - I want to know what you think.

Visit my web site to learn about gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Pop goes the weasel (tree)

As written in my book Roots Demystified, Change Your Gardening Habits to Help Roots Thrive, amendments are materials such as sand, peat moss, compost, and rice hulls have been added to the planting holes to supposedly improve drainage and keep the soil loose and friable. Fertilizers, such as blood meal, cottonseed meal, greensand, and wood ashes, are those ingredients added to provide mostly nutrients. Some amendments, such as compost, are thought to do both improve drainage and act as mild fertilizers.

One of the best studies of the effect of amendments for fertility was done at Oklahoma State University at Stillwater by Joseph Schulte and Carl Whitcomb. They planted 108 silver maple trees with 11 different soil treatments and a control (untreated planting hole). One conclusion was: "no benefit was derived from the use of soil amendments either with a good clay loam soil or a very poor silt loam subsoil." They found that the control plantings with no additional amendments generally outperformed the plantings with amendments for drainage and fertility.

The loose soil of the amendments in a traditional planting hole makes something like an underground swimming pool full of water when it rains hard, drowning important root hairs. Adding a lot of amendments only leaves the roots unprepared for the shock of what lies beyond the amended area. (And nobody can amend the area of the mature root system seeing as how much wider it is than the foliage.) Often the roots fail to make it out of the well-amended hole and merely circle around in the loose planting medium, rendering the trees likely to blow over during a storm. The trees most tolerant to wind are those with the widest root systems. Or, as the photo shows, not spreading the roots when planting can allow the tree to simply pop out of the ground when hit by a car or pulled out by hand.

Please post a comment - I want to know what you think.

Visit my web site to learn about my gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Mulch 'Mators

The perfect tomato is the Holy Grail of many gardeners. Especially in the coastal, marine-influenced climate where I live. I’ve watched neighbors plant tomatoes where the summer fogs are frequent and nurture, worry, persist and try every way they read in the books and magazine articles to eke out a handful of tomatoes. Probably at a real cost of $10 per tomato, or more. Whereas just 2 miles east, over the high hump of the land that captures so much summer fog, tomatoes thrive. So, I buy them at the farmer’s markets and save lots of money and elbow grease.

Back in the ‘30s a man named John Weaver had the patience to excavate entire root systems. He dug a trench along side of the base of each plant and proceeded to excavate, scrape, and dust his way through soil – much like an archeologist at work - to reveal in exquisite detail the full extent of a plants root system. He (or someone else – the book makes no comment as to who did the drawings that resemble etchings) mapped mostly economic vegetable crops. Weaver must have been the Saint of Patience. I often wondered if he had a wife (no search found any clue) who could understand his work and have the same patience he must have had.

In Weaver’s experience, a tomato seed planted in ideal outdoor soil, with no transplanting involved, can grow a taproot to the depth of 22 inches at a rate of one inch per day. The tomato is yet another vegetable that prefers to grow a taproot, which is often damaged during transplanting. Young seedlings transplanted several times into increasingly large pots before their final move into the garden will probably end up with a root system more fibrous than that of tomato plants planted by seed in the garden which are allowed to grow a conventional taproot. However, transplanting tomato-plant stems deep into the soil will produce many adventitious roots along the length of its stem (See Weaver’s illustration.), creating a great root system early in the life of the plant, more advantageous than seed grown in the garden.

The illustration is drawn on a one-square foot grid (Taken from my book Roots Demystified, change your gardening habits to help roots thrive.) and shows how massive the root system is for one plant. At seven feet wide it changes one’s perspective of how much mulch is required to keep all the roots happy. In cool climates you might experiment with paper from an office or home shedder to help reflect light into the canopy of the plant. Turn all those shredded unsolicited checks from your credit company into wonderful tomatoes!

I don’t know of anyone planting tomatoes by direct seeding in the ground. Do you?

Please post a comment - I want to know what you think.

Visit my web site to learn about my gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Roots Grow Up!

Surprisingly, many of a tree’s feeding (not “structural” roots) roots grow up, not down. In a paper published in The Landscape Below Ground (International Society of Arboriculture, 1994. pg. 3), Professor Thomas O. Perry states “Most tree roots range in diameter [from that of] of a lead pencil to the size of a hair. These smaller roots…grow upward into the surface inches of soil and the litter layer.”

The significance of the importance of the most aerobic layers of the soil and duff can be seen in a simple study using potted tree seedlings. You can see the dramatic difference in the illustration of growth between the three soil depths. The seedlings in the pot on the left are growing in soil collected from the top two inches. The middle pot has soil only from the 2-4 inch depth of a forest floor. The pot on the right is trying to grow in subsoil.

The top two inches is so vital to a tree’s health, whether it’s native or ornamental. This is also the favorite two inches for all the plants in a humid climate with periodic rains. Take away that top two inches by planting it to lawn, raking the duff up for “a cleaner look” or allowing so much foot traffic that the roots are exposed, and you have a disaster in the making. This is perhaps the most important illustration in Roots Demystified because it so graphically reveals where tree and shrub roots prefer to grow and feed.

The photo is of a cross-section of three feet of soil beneath a vineyard. Most of the roots are in the top foot or so of the soil. Below that level it gets increasingly more like clay subsoil. (If you click on the image to enlarge it, you will see a few roots below the first foot and even a few that found the lens of gravel.)

The aerobic-loving soil life – where you find the most soluble nutrients - needs to breathe. The deeper you go, the less aerobic you get, and the number of “good guys” (beneficial soil flora) will rapidly diminish. Studies done with agricultural plants provide a lot of useful information. One example is alfalfa, it can grow roots much deeper than peach trees can, yet both get most of their moisture (along with nutrients) in the top one to two feet of the soil.

But trees still need “dirt”. Perry puts it quite succinctly when he says that trees on soils as little as five inches thick produce only poor tree and shrub growth. (one can then imagine how far the roots must grow laterally in the shallow soils to gather sufficient moisture and nutrients.) You can get fair growth with a ten-inch depth, good growth at 16 inches and excellent growth with 20-30 inches of topsoil. Most remarkably, according to Perry, the tree vigor is likely to gradually decrease with soil deeper than 30 inches. (The Landscape Below Ground, International Society of Arboriculture, 1994. pg. 9)

A PRACTICAL TIP FOR GARDENERS
As I’ve often said: mulch, mulch, mulch. Replicate the duff that forms in a natural forest. Establish as many permanent pathways as possible. Try to let the pathways “breathe”—allowing the air to flow into the roots and the carbon monoxide to be expelled. You can use chipped bark, chipped tree trimmings, gravel or whatever local material suits you.


Please post a comment - I want to know what you think.

Visit my web site to learn about my gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Living With the Roots of an Oak Tree

I laugh (and cry) at the little orange fences they put around oaks during construction. They are nearly worthless. While it keeps vehicles for hitting and scaring the bark, it in no way protects the feeding roots.




As a maintenance gardener I’ve had to dig up a few oaks. And just below the ground the roots have a covering much like bark. Bark absorbs very few nutrients. In a study of 25-year-old apple tree in the UK found that the first four feet from the trunk accounted for less than 10% of all the water and nutrients absorbed.

The wobbly-orange fences are, at best placed at the edge of the foliage. A good start as it may help to keep water off the trunk’s base. But this is a far cry from protecting the majority of the root system’s feeding roots.

In the photograph to the left, the construction company dutifully surrounded the oak’s dripline. But all the machinery and the house itself cover what used to be the leaf litter, duff, and organic mater (humus) that once both fed and protected the young feeding roots.

The tiny root hairs, that live for just a day or so, tend to grow up into the fertile strata of the humus and duff zone. They, like all plants, want to be the first to capture liberated nutrients as they become avaiable. As one researcher put it—“roots grow up not down”. While a bit overstated, they fact is the youngest rootlets and their root hairs reside well beyond the canopy of the tree, where all the construction is taking place. (Learn more in my book Roots Demystified,)

(See my Blog of March 31st to see diagrams of the extent of a roots wanderings.)

At one-half to thee times, or more of the width of the dripline roots gather nutrients and moisture far from the trunk or even the canopy.

The photo (on the above right) of the chairs face south along the Big Sur coastline are a good attempt to protect to crown of the young California live oak from moisture in the summer. The gravel does allow rain in the winter to percolate down along with oxygen and harmful gases escape. The compacted gravel is a bit hard on the feeding roots, but the tree seemed health. Perhaps this is one solution to living among oak woodlands.

Please post a comment - I want to know what you think.

Visit my web site to learn about my gardening books.

All Rights Reserved. Copyright 2008

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Mounded Plantings, Irrigation-Free

I’ve started the annual ritual of mulching the perimeter of my irrigation-free planted mound. I lay down 5 or so sheets of newspaper and then several inches of compost made of rice hulls and manure.


I've always wondered why the former Xeriscape Council only advocated a savings of up to 75% on the water used for outdoor irrigation. Why only 75%? Why not shoot for 100%? After seven years of trial and error, I came up with a mound-and-plant system some eight years ago which has required no additional irrigation beyond the day of planting, even during the most protracted California drought in over 100 years.

To begin such a planting scheme, I stockpiled chunky wood chips (not sawdust, which settles down too much and doesn't drain well) from local tree-trimming services. This is critical that the wood chips are mixed with the fresh green, fresh leaves, and small branches. The leafy green parts are critical to compensate for the carbon in the woodier chips.

Next, I used a spading to just crack open the soil beneath the planned area of the mound, not heaving it. Then, I built an active compost pile and plant directly on top of trimmings. Because tree chips are so high in carbon, I layered or mixed them with some manure if required—if there were not enough leaves. I'd guesstimate that a good starting ratio for your own experiments would be one part manure to three or four parts chips. I would use other types of high-nitrogen materials if needed—wet kitchen scraps, fresh grass clippings, green-manure crops like buckwheat, vetch, bell beans, and clover—to help decompose the woody chips. The more nitrogen added, the faster the mound will decompose and the greater the nitrogen supply for the growing plants. I piled this mixture of high-carbon and high-nitrogen materials at least 50% higher than I wanted the final mound to be, and sometimes up to double the height. I watered each layer as I went and made sure all material was moist.

Next, I covered the mound with a soil cap at least eight inches thick—the thicker, the better. I used a mixture of 50% rotted turkey bedding and 50% native soil for the top layer. The soil cap insures good drainage, a neutral soil temperature, balanced nutrition, and good initial growth for the transplants. The plants are placed into the soil cap and watered in thoroughly. I used five sheets of overlapping newspapers covered by turkey-bedding mulch cover the soil cap and, like a "biodegradable herbicide," suppress all weed seedlings. It’s best for me to plant in the fall so the winter rains continue to keep the composting heap moist and to allow the roots to grow. Drought-resistant plants are essential. I used white, pink, and blue rosemary, grey and green santolinas, rhue, many types of lavender, native sages, euphorbia, daffodils, and society garlic (which the deer started eating a few years later).

Once the mound started rotting, the root-hairs of the plants followed the decomposition to take advantage of the newly available nutrients. Plants are "smarter" than we often acknowledge; their roots won't grow into areas that are too warm due to thermophilic (hot) decomposition over 110 F.

Eventually, my "research" mounds settled down, the shrubs rooted fully into the native soil—the new mound is a wonderful, curvilinear feature in my landscape. Mounded plantings, which seemed to me to be a heap of contradiction at first, have become one of my preferred techniques for quick no-till soil drainage, and they don't require any drip-irrigation hardware or precious water. In hotter climates a bit of drip irrigation will probably be needed. If you experiment with this, please let me know.

There's more about planting on mounds in my book Roots Demystified.

NOTE: I live in a moderate-summer climate with a moderating marine influence. If you attempt this mound-and-plant strategy in your own area, I suspect you'll have to make some changes in plant selection and the time of year you’ll be planting. For example, I once installed a test plot at Kit Anderson’s house near Burlington, VT, when she was editor of National Gardening Association magazine. I spent hours in the muggy August heat, along with members of the NGA staff, hauling in manure-rich straw, distributing Kit's garden clippings and leaves and planting a range of perennials which normally thrive in this northern latitude (within one-half mile of Lake Champlain). Many of the crew were skeptical that such a bizarre method would work, and it didn’t—growth in the late summer was not sufficient to allow many of the perennials to weather the winter in good form. I suspect that timing was the main problem, and that mounds in hot-summer areas need to be planted in early spring so the roots can be deep enough by fall to tolerate the frozen months. You'll have to experiment in your soil and climate. I suspect the mound should be started in the Spring were there is summer rain.

Please post a comment - I want to know how the mound system worked for you.

To see more detail of the illustration put you cursor over the image and double click.

All rights reserved, Copyright 2008

Visit my web site to learn about my gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Floppy Trees & Tomatoes (and a small rant)

Don’t let your tomatoes flop around and be fodder for a frost.

I wrote in an early draft for my book Roots Demystified:

“There are all kinds of ways to start plants well ahead of the time when it’s safe to transplant them into the garden. These include cloches (bell-like glass coverings), plastic-tubing walls filled with water to catch and hold the sun’s heat, and sunny windowsills or greenhouses. It’s been my observation, however, that large plants started well ahead of transplant time may not produce tomatoes any sooner than small seedlings planted after any threat of frost and in warm soil.”

I gave a talk today about roots. The conversation turned to tree trunks and how to best stake them. I talked about how the nurseries often tie the whole tree, from its base to nearly the tip of the growth, to a 1”x1” stake. When the poor trees are released from this bondage, they simple flop over. Trees need to blow in the wind to develop a sturdy trunk with a healthy girth. (See the illustration to see how to determine where to stake a flopping tree so it can move in the wind to be healthier tree.)

A woman came up to me after the talk to say last year she had started some tomatoes early in a Wall-of-Watertm—plastic-tubing walls filled with water to catch and hold the sun’s heat. When released from this frost protection, the plants immediately fell over—like the staked trees. She had to tie each new shoot to the hog-wire trellis she uses to grow tomatoes. The tomatoes set out after the average date of our last frost thrived. The wind buffeted them and they rambled up-and-through the hog wire with carefree abandon.



Begin Rant
I had to go to the plant nursery for a friend after the talk (on April 5th). The weather was an ideal 70 F plus and throngs of people were at the nursery. There were also throngs of tomato seedlings. I wanted to yell “All the ’ole timers say never set tomatoes out into the garden until after May 1st as there is still a chance for a hard frost in April.” But the nursery was happy to sell these tender seedlings to gardeners’ dreaming of early tomatoes. Most nurseries prey on those who try to jump-start tomatoes. Shame on them, but money at any cost is money I guess.

I suspect some will find brown-green plants laying flat on their faces before May 1st. (Some of the low-lying vineyards had to spray water last week on the vines to help prevent damage to the new buds as the temperature hovered around 32 F.)

Patience furthers. A gardener needs to calmly wait until the soil warms up before planting the treasured tomato seedlings. (Besides, there’s probably lots of weeding or composting to keep you busy!)
End Rant

Please post a comment - I want to know what you think.

Visit my web site to learn about my gardening books.

All Rights Reserved. Copyright 2008

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Lettuce Consider Garden Diversity

As spring's passionate climax approaches, I'm thinking about how much diversity does a garden need?

My mind drifts back to 1982. As I wrote my rough proposal for a book on edible landscaping while at Oyster Bay, NY. (Designing and Maintaining Your Edible Landscape – Naturally; 1986, Metamorphic Press.) I gazed across a well-clipped estate lawn to an recently-abandoned tennis court.

After just a few seasons of neglect, every fissure in the asphalt had been filled with grasses and a wealth of herbaceous weeds. More remarkably, well-anchored saplings of the mimosa tree (Albizia julibrissan) were already several feet high and beginning to heave the tarmac. In less than a decade, those mimosas' will have completely cloaked the court's rubble with a prosperous, verdant forest. How quickly nature can reclaim what we pretend to husband or nurture. All the human effort we put into cultivated gardens is dwarfed by even the casual momentum of nature. Once untended, even the most environmentally-kosher garden soon returns to nature's bosom. Buried within this steady, powerful momentum are the seeds of nature's renewal—which are more powerful than any human garden.

I visited the site of Allan Chadwick’s Covelo, CA garden just a few years after it was abandoned. Allan Chadwick was the guru of French-intensive, biodynamic gardening. Apprentices flocked from around the world to learn from this strident and demanding teacher. Yet, the garden was a riot of weeds. The most prevalent were lemon balm and comfrey. Proof that their composting was not hot enough to kill all garden seeds. The comfrey was (and probably still is) a biological nightmare. Just a tiny piece of root can sprout become a huge plant in matter of a few years. Probably the apprentices had skimmed bed of comfrey for compost, but skimmed deep enough to gather the crowns of the plants. I used to plant comfrey, some 38 years ago during the early days of my infatuation with intercropping, companion planting, and the silica-enhanced comfrey At the time I assumed that planting it in with vegetables would allow its deep roots to bring up special minerals from deeper places than the vegetables could reach. I regret to this day that the tillage of those gardens spread unwanted comfrey throughout the beds. Now my comfrey is five feet from any tillage, is never watered, and the leaves are cut well above the crown for compost. Yet I have to struggle to remove the roots that have found the moisture of the raised bed with it’s lemon bush. Slow learner I guess. Now, in any design I do for a client there is no comfrey to be found.

A common theme in the sustainable/organic/permaculture world is the premise "diversity equals stability." I wish the continual references to "Diversity", “Climax”, and “Stability” would end. While diversity within an ecosystem allows for a complex interaction between all the elements, plants, animals, and people; it is not a panacea. A “mature, climax” forest is often the model of “stability”. Yet winds knock down trees to open up little meadows to start the whole process again. The edges often have to repeat what lead the forest to have a mixture of trees and other plants. Trees die to be replaced by some of the same progression leading up to a climax.

A climax forest is not always the natural climax. Vernal pools, sand dunes, chaparral, bogs, and other ecosystems thrive without forming a continuous canopy of trees. Too often in gardening books, what appears to be a great way to garden is based on the experience of tropical ecosystems. Using tropical diversity as a model is childlike. While the tropics often have lots of vertically-integrated plants, the temperate American landscape, with its hardwood forests, meadows, and prairies, is less vertically complex and is more adapted to the growth of annual plants than the tropics. More importantly, in the tropics the nutrients are stored above ground in the biomass. Whereas in temperate ecosystem, the nutrients are stored in the soil. Randomly-chosen diversity or complexity doesn't necessarily provide any special benefits.

A good example is the wish that beans climbing corn will feed the corn with nitrogen. However, beans don’t “share” much of their nitrogen nodules with other plants while they're growing. unless they go into severe drought, die, are mowed, grazed, and after tilled under just as blossoming begins. (See page 49 of Roots Demystified, Change Your Gardening Habits to Help Roots Thrive. 2008, Metamorphic Press.) The legume is selfish, it is building up a supply of nitrogen in its rots to move it into the formation of seed. Only then, will the nitrogen become available to other plants. But most of the nitrogen will, by that time, be in the seed, not the foliage or roots. That’s the temperate dynamics. In the tropics, nutrients cycle so fast that even some leaves falling off the older stems of the bean plants rot and release some nitrogen on the surface of the thin layer of soil.

However, in both climates it is well proven that a green manure crop of any number of legumes greatly increases the total amount of nitrogen. Crop rotations where a field or planting bed is left to fallow for a year with legumes also increases nitrogen for the next crop.

But our garden's diversity must be, to our current knowledge, composed of the proper plants. For example, the kudzu vine is theoretically a multipurpose plant with many edible parts and useful fibers. Adding kudzu would be another unit of diversity in your garden. But you better leave town before your neighbors come after you as the kudzu vines entangle everything that's moving slower than 25 miles-per-hour! Kudsu is an extreme example of exotic plant from Japan and China gone wild. Kudzu plants grow rapidly, and may extend to100’ in length at a rate of about one foot per day.

More subtly, you may think twice about nurturing edible lamb's-quarters (often treated as a weed) if you're growing lots of heirloom tomato plants because this "weed" also harbors verticillium wilt—the Achilles Heel of many non-hybrid tomato plants. Too much diversity, or the wrong kind, only promotes that universal dynamic called entropy via chaos.

Too much diversity, or the wrong kind, only promotes the universal dynamics called chaos and entropy. Nonetheless, the organic movement will only continue to grow both literally and figuratively.

In my opinion, gardeners are not as important to nature as we think, nature eventually takes back everything and we should endeavor to stay humble and in our place—relative to the grander scheme of things. As George Carlin so eloquently observed in his 1992 (a man ahead of his time) HBO special: "Save the planet!? Are these fucking people kidding me? There's nothing wrong with the planet that it can't fix. We still haven't learned how to care for one another—and we're gonna save the fucking planet? So, take care of yourself. And take care of somebody else."

Please post a comment - I want to know what you think.

All rights reserved. Copyright 2008


The image is of a kudsu vine covering two tractors and a forest. Photo by Jack Anthony, from
http://www.yahoolavista.com/kudzu/

Visit my web site to learn about my gardening books.

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Radio Ramblings

Radio shows can discombobulate me. (Notice bob in the word.)

I was on the radio last night. The other guest was very fascinating as she described wining a gold medal twice at world’s most prestigious flower and garden show—the Chelsea Garden Show in the UK. This was a display put together by an American, trouncing dozens of garden displays by British gardeners. Like the California bread maker that had best of “show” in a French competition. Americans are giving some of Europe a run for their money.

When the conversation drifted into what the Queen was wearing when she stopped by the display garden, I got a bit frustrated as roots—I was there to promote my book Roots Demystified— and the Queen of England don’t seem to have much in common.

Finally the conversation turned toward my book. I got flustered which is rare for me on a radio show. There were so many things I realized later I wished I said, but had slipped my mind. Such as:

Where should I feed my shrubs and trees? This question came before I explained that trees and shrubs have roots that extend well beyond the canopy—sometimes as far as three to four times the radius of the trunk-to-dripline (the edge of the foliage). The illustrations on his blog are taken from my book and shows how dramatic the root spread can be with a walnut tree and two apple tree as examples. (Click on the illustration to get a bigger version that shows how far the roots travel from fruit trees.)

What other plants beside mint have long running roots? I said bamboo and Bermuda grass, failing to mention the illustration in my book showing Bermuda grass with roots nearly six feet deep. I forgot all about kikuyu grass that is so aggressive it makes Bermuda grass look tame. I first saw it at the Esalen Institute, Big Sur, CA. To stop its on slot into the vegetable garden they had to keep a two-foot trench open between the grass lawn of kikuyu grass and the vegetable garden. Roots can travel sight unseen great distances, even if they are not as diminutive as a grass. I failed to remember the popular tree near town that has crossed under two lanes of asphalt to pop up on the other side.

I explained how Steve Solomon was able to dry farm carrots one foot apart along the row with five feet between the rows. I neglected to say his estimate was planting eight times further apart than that recommended by followers of the French Intensive-Biodynamic method only reduced yields by one-half. And all without irrigation.

There is much more detail and suggestions in my book Roots Demystified.

Would I go back on the airwaves again? You bet. But not with the Queen of England!


Please post a comment - I want to know what you think.

To see more detail of the illustration(s) put you cursor over the image and double click.
All Rights reserved. Copyright 2008

Visit my web site to learn about my other gardening books.

I have lost the usual way to leave comments. To do so, simply click on the "___ Comments" below or click on the Blog's name under Blog Archives. Thanks, Roberts

Raised Beds-It's Spring!

Raised beds in the garden, not the bedroom.

The simplest and most inexpensive way to make raised vegetable beds is to cultivate and rake soil up into a mounded shape. This type of “bed” should in no way be considered a raised bed made by the cultivation method often referred to as the French intensive-biodynamic raised bed. See John Jeavons classic—How to Grow More Vegetables: Than You Ever Thought Possible on Less Land Than You Can Imagine. The methods outlined by Jeavons produces a proper mound of slightly-raised soil and offers the best way to improve the tilth and fertility of your soil.

Many gardeners, however, prefer to construct formal raised beds framed within masonry, plastic, or wooden sides. These sides retain the soil while imparting order and efficiency to the kitchen garden and helping to define it. Formal raised beds also provide a number of other advantages:

 Enhanced drainage for better growth.
 Soil which warms slightly sooner in the spring.
 Sides which help keep soil or mulch from spilling into paths.
 A structure which allows wire mesh to be added to the bottom of a bed to exclude tunneling pests such as moles, gophers, and hedgehogs. However, It’s obvious that carrots prefer a deep soil (as shown to the left) with good tilth and drainage, free of rocks and obstructions that can produce deformities. In less than ideal soils, cultivate as deeply as possible before seeding. Carrots are best grown in double-dug beds with vigilant trapping of gophers, or in boxes raised 24 inches above the soil line and constructed with wire bottoms to deter gophers or other underground gnawing pests. (The root system of a carrot is taken from my new book Roots Demystified, Change Your Gardening Habits to Help Roots Thrive. The grid is one-foot square.) This shows that in a deep soil carrots are able to grow nearly eight feet deep and five feet wide!. This means that even a 24-inch raised be leaves plenty of roots for vegetarian gophers to feast on. This illustrates why extra water and nutrients are needed to satisfy a normally vast root system. (Click on the image to get a clear, detailed view of the illustration as it appears in the book.)

When building garden boxes, line the bottoms with one-half-inch aviary wire, which comes in four-foot-wide rolls. One-inch chicken wire, while less expensive, may allow baby gophers to sneak inside the box. The aviary wire also has more galvanized metal and lasts longer in the ground. Even with this protective barrier in place, the taproot and many other roots will be eaten at the bottom edge of the wire.

 The Cadillac version is to use one-quarter-inch hardware cloth because it doesn’t rust through as quickly.
 When preparing beds for planting, be sure to work the soil with a spading fork to crack open the soil before building the box. After the soil is in, use a flat-bottomed spade so you don’t damage the wire.
 A way that pathways between beds can be cleaned and tended without disturbing plantings.

Raised beds also have certain limitations or drawbacks:

 A formal raised bed with solid sides will cost more and require more time and effort to construct than a simple mounded bed.
 Some gardeners find the angular geometry of the raised-bed structures unaesthetic. (Beds can, however, be masked by perennial plantings or low evergreen hedges.)
 When watering a raised bed with drip irrigation, extra effort must be made to bring the water supply into the bed unobtrusively.

There are many materials which can be used to construct a raised bed. Each has its own unique mixture of attributes and imperfections:

Used Bricks (Recycled)
Pluses:
 Very good looking; construction has character when first built.
 Since bricks are fairly narrow, the finished wall doesn’t take up excess garden space.
 Wire mesh is easily added to the bottom.
 Uses recycled materials.

Minuses:
 Expensive if new.
 Requires some masonry skill or practice to construct.
 In areas where the ground freezes, requires a poured concrete base.

Cinder Blocks

Pluses:
 Wide enough to sit on while gardening.
 If unmortared, easier to work with than brick.
 Can be built on a base of packed gravel
 Easy to add wire-mesh bottom .

Minuses:

 Not easily found as recycled material.
 Best used only for square and rectangular beds.
 Thick blocks take up garden space
 Looks gray and “industrial,” like concrete.
 The large holes in the blocks, usually placed facing up, tend to fill with mulch and soil from the bed.
 Unless mortar and a concrete base are used, the blocks will often settle in a slightly skewed position.

Plastic “Wood”
Pluses:
 Easy to work with, like lumber. No splinters.
 Made from recycled consumer plastic waste.
 Has a long life and won’t rot.
 Easy to add a wire-mesh bottom.
 Easier construction of odd-angled shapes such as octagons or pentagons.

Minuses:
 Up close, looks very fake.
 Expensive compared to lumber.
 Requires screws instead of nails for sturdy attachment.

Recycled, Untreated Rot-Resistant Lumber

The use of the two main rot-resistant lumbers available, redwood and cedar, is controversial due to environmental issues. They are, however, still the easiest material for building raised beds. (Use of recycled wood lessens environmental impact.)

Pluses:
 Good-looking natural surface.
 Available as recycled material.
 Easy to work with; no mask, gloves, or goggles required when using hand tools.
 Easy to add wire-mesh bottom.
 Can be used to construct odd-angled shapes.

Minuses:

 If in contact with the soil, may have to be replaced within 4-20 years. (Note: redwood heartwood can last this long, but white redwood sapwood usually rots within four years and should be avoided.)

So, the choice is yours. Happy gardening.

Please leave a comment- I'd like to hear from you.


To see more detail of the illustration(s) put you cursor over the image and double click.

All rights reserved. Copyright 2008

NOTE: The comments section at the bottom of the post has disappeared. Click on the "___ Comments" button or the title under the "Blog Archives". Thanks, Robert

Visit my web site to learn more about my gardening books.

Shameless Self Promotion

Roots ain't sexy. But plants need them to be healthy.

Thus I wrote a book about how roots really grow and ways a gardeners can have a better garden via healthy roots - Roots Demystified, Change Your Gardening Habits to Help Roots Thrive.

Check out my web site for more information (sample pages) and how to order: www.robertkourik.com

The book has been listed in Publisher's Weekly. They receive 1500 books per month and only list 450.

The best news came from the Midwest Book Review (one of the top 4 book reviewers for librarians):

“Superbly written and thoroughly 'user friendly', ‘Roots Demystified’ is profusely enhanced with twenty-five illustrative graphics showcasing extraordinary illustrations of excavated root systems in their entirety. A compendium of practical, comprehensive, and exceptionally well organized information, advice, tips, and observations that will benefit novice gardeners and seasoned professionals alike, ‘Roots Demystified’ is an excellent and strongly recommended addition to personal, professional, academic, and community library Gardening/Agriculture/Horticulture reference collections and supplemental reading lists.”

Here's my speaking schedule for now. 

March 30th. - On the radio on Michelle Anna Jordan's show "Mouthful" along with the extraordinary gardener Kate Frey of Fetzer Garden fame (who has also won prizes at the Chelsea Garden Flower Show in the UK.) 7-8PM on KRCB 91.1, in Santa Rosa CA 90.9 both on the FM dial.

April 5th - Book signing at Copperfield's Books in downtown Sebastopol. 11AM to noon.

April 15th (after paying your taxes - it's free!) - Oakmont, the Berger Center. 10-11AM (email me for directions - rkourik@sonic.net)

May 3rd - Lecture at Harmony Farm & Garden Supply, Graton, CA 10-noon.

May 18th - Book signing at Sonoma Mission Gardens 1851 Craig Ave., Sonoma, CA 4-6PM. 

I hope to meet you at one of these events.