Noxious Trees of Heaven in Elyria Canyon Park

Despite the valiant efforts of the Mt Washington Beautification Committee, the Trees of Heaven, Ailanthus altissimus, have not been eradicated from Elyria Canyon Park, yet.  Read more about this invasive weed tree on the California Invasive Plant Council, the Plant Conservation Alliance’s Least Wanted List, or the Center for Invasive Species and Ecosystem Health websites.

Dead Grove of Ailanthus Trees


Last year, Beautification Committee members secured funding through both the Arroyo Seco Neighborhood Council and the Greater Cypress Park Neighborhood Council because the boundaries of the park include both districts.  Professional herbicidist Bill Neil was hired and he applied herbicide directly to the trees, killing the largest stands in the park, however, young sprouts of this fast growing nuisance are returning.

If the Trees of Heaven continue to proliferate in Elyria Canyon Park, they could begin to threaten the already endangered native California Black Walnut Trees there.  In an effort to curb the spread of Trees of Heaven in Elyria Canyon Park, the Beautification Committee members are once again in the process of seeking neighborhood council funding for the 2011/2012 fiscal year.

Tree of Heaven Sprouts below Red Barn


Because of the particularly wet winter, new sprouts of the Tree of Heaven are especially vigorous this year.  The Beautification Committee hopes to have funding in place to begin chemical treatment in a few more months before the plants lose their leaves.  Herbicide needs to be applied while the plant is growing and not during its winter dormant phase when it drops its leaves.  If there is both a fall and a spring followup treatment, we expect to be able to get most of the problem under control, however total eradication may take many years.

If Trees of Heaven are cut down or pulled out, they will quickly return because a systemic poison is needed to destroy the roots.  The herbicide that is used targets only the plant that it is applied to and it quickly breaks down so that it does not cause any harm to the environment or to surrounding plants.  While we would prefer not to use herbicides in the park, the particular virulence of the Trees of Heaven demands such drastic measures.

Tree of Heaven sprouts near the Ranger Station

Trees of Heaven look superficially like Black Walnuts, but the leaves are much larger.  Trees of Heaven have a characteristic foul odor and they are often called “Stinky Trees” by folks.  A single sprout on private property can soon turn into a grove of trees that spreads to neighboring properties, crowding out both native plants and cultivated areas.  The roots of the Trees of Heaven can compromise the foundations of homes, sewer lines and septic systems.  If you suspect you may have Trees of Heaven, you may want to participate in an eradication program we have begun in Mt Washington.  For a nominal fee, professional herbicidist Bill Neil will safely treat the trees in your yard, however, removal of dead trees remains the property owners responsibility.  Nip your problem in the bud and don’t wait until you have a grove of 60 foot tall trees that multiply each time they are cut down.

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