Plants You Do NOT Want to Encourage in El Dorado County!

mad gardenerNot All Local Plants are Good Local Plants.

For all that there is to enjoy about your native plants, it shouldn't be too hard to understand that what we call weeds are also native plants ... somewhere else! They got here from someplace (usually Europe) sometimes on purpose, sometimes as hitchhikers. People coming to California during the gold rush started the big boom in introduced species when they packed up everything – including seeds, some for planting, others as hidden surprises – and came west. That trend has not stopped to this day, and travelers, freight shipping, birds, and wind all contribute to seed migration. Just as happens with animals, when a new plant arrives and finds no natural predators, reproduction continues unfettered. Today we can drive around the county and see plenty of plants that have, in some cases, become a dominating life form in the field: acres of yellow starthistle, roadsides lined with yellow broom, and often large stands of Ailanthus.

broom for saleIf you are a property owner, you will do yourself (and the rest of us county residents too!) a big favor if you will learn to recognize these pests and remove them. And do NOT be lured into planting a pest because you see it offered for sale at some Big Box nursery! You see big displays of broom plants for sale every Spring. Not good. Don't fall for it. Want to buy the right stuff? Check the Garden page. Meanwhile, review these invasives and smack'em if you see them.

Questions should be addressed to Annie Walker, Invasive Exotics Chair, or call 530.626.3678

Remove ANY of these plants you find on your property...

starthistleStarthistle: As good a place as any to start. Centaurea solstitialis is an obnoxious (and noxious) plant found just about everywhere, even creeping higher and higher to now be found above 4000 feet. It is distinctive (to say the least): finding new growth with gray-green foliage and winged stems gives you your first opportunity to remove these bad boys. If you fail to take action you will end up with a bigger job as you attempt to remove the sharp-spined flowering plants that will take over your fields given the slightest chance.

Here's why you want to be proactive in removing starthistle: "Eradication is not often practical for yellow starthistle, but in previously un infested areas it may be possible to eradicate new small invasions. An effective eradication program is closely tied to prevention."
— UC Davis Starthistle Information

Ailanthus: More commonly known as tree-of-heaven, and the tree of A Tree Grows in Brooklyn, Ailanthus...from a Moluccan name ailanto meaning "sky tree".
The Moluccan Islands are a part of the Republic of Indonesia. was brought to California by the Chinese who arrived during the gold rush. While it may be highly regarded in China, it is not one you want on your property, unless of course you think you would enjoy the foul smell; one of the other common names is "stinking sumac" because all parts of the tree, including the flowers, have a bad odor.
"Invasive and difficult to eradicate. Weak wooded. Short-lived. Messy..."- Missouri Botanical Garden

Dandy! Get the saw...

Any of the Broom Bunch...

broom exampleMore likely found along county roads than in your yard, you still want to take any opportunity to remove most any form of broom when you can. We have both Scotch broom (Cytisus scoparius) and French broom, Genista monspessulana. At first glance these both look pretty much the same: dense shiny green leaves and loads of bright yellow flowers with that familiar banner, wing, and keel; the brooms are in the Fabaceae family, along with peas, beans, clovers, and hundreds of other plants with that distinctive flower.

Why is broom a problem? "It displaces native plant and forage species and makes reforestation difficult. It is a strong competitor and can dominate a plant community, forming a dense monospecific stand." -Cal-IPC

deerweedNOTE: on the good side, we also have a genuine native plant called deerweed (Lotus scoparius) which can look very similar to a small Scotch broom plant. Flowers (shown) are mostly yellow in the Calflora pictures, but there is more reddish or ruddy coloring to the plants seen around here. This is a chaparral plant and can be found along the road up to Marshall Hospital from the Goldorado Shopping Center (Bel Air Market) part of Cameron Park, and around the American River. Be aware, this one is a keeper. Don't remove it by accident.


stinkwortStinkwort: With a common name as pretty as that, why would you want to remove it? (joke!) A fairly recent addition to the list of unwelcome plants invading the county,. Dittrichia graveolens is a "fall-flowering, sticky aromatic annual (family Asteraceae) that appears to be rapidly expanding its range in California." Note that if you read the Calflora accounts, El Dorado County does not yet show any observations. That will change because it has been found "at the Bass Lake off ramp, on both sides of the freeway."


eggleaf spurgeEggleaf Spurge: Also called Oblong Spurge, Euphorbia oblongata is classified by the California Department of Food and Agriculture as Noxious Weed List B ("B" rated weeds are more wide spread). This plant has been expanding its population along Green Valley Road (near the turn to the college) and along Hwy 193, the road to Traverse Creek. Ironically, it's pretty close to the tamarisk (see below).
"Euphorbia oblongata (oblong spurge) is an annual forb/herb (family Euphorbiaceae) found sporadically in California. This plant may be toxic to humans. It is inedible for wildlife and inhibits the growth of surrounding plants."-The California Invasive Plant Council (Cal-IPC). It can be found along Missouri Flat Road near the school entrance, and also along Hwy 193 near Kelsey, curiously close to the tamarisk location mentioned below.

Two Curiosities for El Dorado County...

Of course there are many more invasive plants around the county, but two plants that are big problems elsewhere, tamarisk and pampas grass, do grow here but (probably) won't spread because it's too cold. This picture of pampas grass was taken along Greenstone Road but you can see it in many places around the lower elevations in the county because people actually buy it and use it as an ornamental landscape plant, like Scotch broom!

If you have ever driven down the coast toward Half Moon Bay you might be forgiven for thinking you were in South America because of the rampant pampas grass (Cortaderia jubata)! The pampas grass we see in this county, by the way, is not native to Argentina, it's native to the Andes. The actual Argentinean pampas grass is Cortaderia selloana and isn't reported in this county. Check this page.)

Tamarisk (Tamarix parviflora), also called salt-cedar, is a weedy shrub of the desert Southwest, was originally imported from Egypt for erosion control. As is usually the case, this good idea turned sour when the plants reproduced like crazy. Now they are a problem in desert riparian areas. Seems odd to me but I have seen it along Mother Lode Drive and also along Hwy 193 near Kelsey. Both places are drainage areas so the wet environment has allowed the plant to get a start. Did seed arrive on a vacationer's tires? As far as I can tell, nobody seems to be reporting it on any of the sites about invasive weeds, so I guess that means it is continuing to spread. Unlikely you will have it on your property, but just in case, now you know.

Weeds Listed for El Dorado County:

Group 1: These species are: a) not currently found in El Dorado County, or b) documented as small, eradicable populations, or c) deemed controllable along a defined eastern leading edge to prevent spread into the Sierra Nevada Mountains. Encourage active control/eradication efforts and education in El Dorado County.

Group 2: Encourage the management/control of isolated populations of these species to prevent further spread in El Dorado County.

Group 3: Other species of concern; continue to increase public awareness and encourage control efforts on public and private lands.

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