Wednesday, September 2, 2009

Invasive Exotics

California alone is home to 4,200 native plant species, and is recognized internationally as a "biodiversity hotspot." Approximately 1,800 non-native plants also grow in the wild in California. Here’s a short list of just some of the invasive plants in California alone.

Data is from the USDA. NAL. National Invasive Species Information Center.

It’s strange that this list does not include three major invasive plants: ice plant [pictured here, Mesembryanthemum ssp.], pampas grass, [Cortaderia selloana], and Periwinkle [Vinca ssp.].

The photo on the left shows how ice plant is invading the native Buckwheat [Eriogonum spp.] The photograph on the right shows a native lupine [Lupinus spp. and subtle red hills covered almost completely by ice plant. Sadly, ice plant was introduced to help stabilize sand dunes. It has escaped from captivity and has spread with a vengeance.

NOTE: "3:1 rule: For every year you delay controlling an invasive plant infestation, it will take three years to regain control."

Air Potato (Dioscorea bulbifera)

Autumn Olive (Elaeagnus umbellata)

Beach Vitex (Vitex rotundifolia)

Brazilian Peppertree (Schinus terebinthifolius)

Canada Thistle (Cirsium arvense)

Chinese Tallow (Triadica sebifera)

Cogongrass (Imperata cylindrica)

Common Teasel (Dipsacus fullonum)

Dalmatian Toadflax (Linaria dalmatica)

Diffuse Knapweed (Centaurea diffusa)

Downy Brome (Bromus tectorum)

Fig Buttercup (Ranunculus ficaria)

Garlic Mustard (Alliaria petiolata)

Giant Hogweed (Heracleum mantegazzianum)

Hairy Whitetop (Lepidium appelianum)

Houndstongue (Cynoglossum officinale)

Japanese Stilt Grass (Microstegium vimineum)

Japanese World Climbing Fern (Lygodium japonicum)

Japanese Honeysuckle (Lonicera japonica)

Japanese Knotweed (Fallopia japonica)

Japanese Spiraea (Spiraea japonica)

Johnsongrass (Sorghum halepense)

Kudzu (Pueraria montana var. lobata)

Leafy Spurge (Euphorbia esula)

Medusahead (Taeniatherum caput-medusae)

Mile-A-Minute Weed (Persicaria perfoliata)

Multiflora Rose (Rosa multiflora)

Musk Thistle (Carduus nutans)

Old World Climbing Fern (Lygodium microphyllum)

Oriental Bittersweet (Celastrus orbiculatus)

Princess Tree (Paulownia tomentosa)

Purple Star Thistle (Centaurea calcitrapa)

Quackgrass (Elymus repens)

Russian Knapweed (Rhaponticum repens)

Russian Olive (Elaeagnus angustifolia)

Saltcedar (Tamarix spp.)

St. Johnswort (Hypericum perforatum)

Scotch Broom (Cytisus scoparius)

Scotch Thistle (Onopordum acanthium)

Spotted Knapweed (Centaurea stoebe)

Tree-of-Heaven (Ailanthus altissima)

Tropical Soda Apple (Solanum viarum)

Whitetop (Lepidium draba)

Witchweed (Striga asiatica)

Yellow Star Thistle (Centaurea solstitialis)

Yellow Toadflax (Linaria vulgaris)

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

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