Saturday, May 1, 2010

Pretty Mustard - Not

Every late winter through early spring Napa Valley, CA celebrates the glorious mustard growing between the dormant rows of grape vines. Many intoxicating and spectacular photographs have been taken of this magical season.

But wait. It’s really a horticultural nightmare. Color photos reveal a damaged soil and ecosystem.

Here’s what they do:

“Indulge in fantasy at Mustard Magic, Napa Valley’s most theatrical food, wine, and art event of the year. The Season’s opulent grand opening event graces every contour of the magnificent, historic three story stone building, home to the Culinary Institute of America at Greystone.
As you stroll the art-filled candle lit spaces, sumptuous offerings of food and wine, living art, and music will entice you at every turn. Bid on art, take a turn on the dance floor, savor gourmet fare in the world famous teaching kitchen and raise your paddle high at the event’s live auction to win exotic trips, Napa Valley sojourns, wine and more!
Tickets are $125”

Here’s what I think about the wild mustard, black mustard (Brassica nigra), growing in the vineyards, as seen in the photograph on the right.

Black mustard is one of the few plants that thrives in heavy, clay soil. Or, in soil tilled at the wrong time; when too wet, which leads to the collapse of the pore structure and loss of air. The fields of mustard are actually an indicator of poor drainage, improper tillage, and a special influence known as allelopathy.

Allelopathy is where root exudates harm the plants around them. In most cases it’s a root’s exudates that is a chemical that stunts or kills the roots of other plants. Wild mustard is such a plant. It tends to favor itself over other plants, thus the swaths of continuous mustard.

To substantiate my theory I point to three events: the mustard usually ends at the edges of the vineyard (as seen above on the left), some vineyards haven’t a trace of mustard-perhaps because they were able to till when the soil was too wet or the soil has good drainage-and mustard can be found outside the vineyards mostly along the side of the road where the soil has been compacted and in fields where too many cows have trampled the soil. The photograph on the left shows the adjacent field next to the vineyard full of mustard.

(As a side point, there is a narrow orange patch of wild calendulas along side of the growth in both pictures. It’s wild because it has “back bred” to a plant with a much smaller flower. How the calendulas got there is a mystery. They are not in many vineyards. Some are in rows adjacent to flower gardens surrounding the winery’s sales room or storage barn. They seem to be unable to take much shade and thrive at the very edges of a field or the interface of the bare soil next to the vines (read Round-Up™) and the edges of the row of a cover crop. Still a mystery.)

Click on both photographs to enlarge them to see the mustard & calendulas better.


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

1 comment:

mommypants13 said...

I'm a new follower, I live in Sebastopol myself, I'm glad you posted this, because my boyfriend and I were just discussing the other day whether the mustard in the vineyards was a good or bad thing.

I have really been enjoying your blog, I was searching for a Sonoma county Garden Blog and yours is so wonderful. Thank you so much for sharing your knowledge with us.