ALIEN INVASION, PART 2:

"SMILAX"

So-called "smilax" (Asparagus asparagoides) is a member of the lily family that originated in South Africa. The plant is called smilax locally and in English Commonwealth countries, but the name smilax also has been applied to another, fern-like plant in California. Asparagus asparagoides can be recognized readily by its blanketing of oak groves, particularly those near 11^th through 13^th Streets in the Elfin Forest. A flourishing example can be seen currently in the large grove just to the left (south) as one faces the bay at the west end of the boardwalk (Bush Lupine Point).

"Smilax" (Asparagus asparagoides).

Photo courtesy of John M. Randall/ The Nature Conservancy

"Smilax" is a vine that rises and spreads from underground tuberous roots. It reaches up to available host vegetation and entwines its way to the top of the leaf canopy in groves of pygmy oaks or other native plants. The "smilax" vine can be recognized by its small (1/2 to 3/4 inch long), shiny green leaves. The leaves alternate on opposite sides of the stem. Crushing the plant between the fingers leaves a pungent, disagreeable smell. The vine grows and spreads so rapidly that it smothers ground cover such as hedge nettle, bee flower and bracken ferns, etc. It also smothers the overlying oak, holly-leaf cherry or manzanita groves in a dense blanket of Smilax foliage. Competing for moisture, nutrients and sunlight, the fast-growing vine can devastate the slower growing natives. It also can prevent native plant seeds under the canopy from sprouting and growing.

The " smilax" vine grows during the winter and spring rainy season, flowering in the winter and early spring with small, white blossoms. By summer the plant begins to dry and leaves turn yellow. Round, bright red berries form before the plant dies. By autumn, the vines die off and become dormant. The stems remain in place as a dense tangle or mat of woody debris. The dead vines provide an avenue for the next generation of "smilax"to climb back to the top of the leaf canopy even faster.

The seeds spread by soil and water movement. Birds that eat the berries can also disperse them.

Controlling "smilax" is best done during the growing period in winter and spring. Uprooting is difficult and seldom is successful permanently except on widely scattered, small plants. The root system is tenacious and extensive. Tearing down the mat and crushing it before berries form is somewhat effective in slowing that season's growth. It can help the oaks compete for sunlight as well. Tearing down the dried debris in late summer or fall might help slow the climb of the next season of plants, but it also could encourage " smilax" seed germination. Additionally, just tearing down the vine does not help the low growing vegetation inside groves. For that reason, the vine debris should be removed and disposed of.

" Smilax" can be controlled chemically during the winter and spring growing season. Spraying the leaves with Roundup, with an appropriate surfactant to penetrate the shiny leaves, is effective. (Individuals may not use Roundup or other herbicides in the Elfin Forest because of federal and state endangered species regulations and also county ordinances.)

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