Though beautifully colored in the autumn, this annual plant can quickly colonize a garden area.
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Kochia might look attractive when it turns red in fall, but this bushy annual with the fine texture doesn’t have the best seed manners.
Often nicknamed “fireweed,” “burning bush,” or “summer cypress,” Kochia scoparia (a.k.a. Bassia scoparia) can quickly colonize an area with its ability to produce up to 15,000 seeds per plant per year.
This plant’s showy fall appearance is why American gardeners began planting the Asian native as an ornamental around 1900. Cattle farmers also planted it as a forage crop. However, kochia’s ability to sprout in poor soil and grow even in drought conditions soon turned it into an invasive weed throughout much of the United States, especially in the Plains states.
Kochia’s look and habit
Kochia grows anew from seed early each spring, eventually reaching heights that in some areas top out at six feet. They look like finely textured bushes with dense branching, but despite the appearance, they’re not woody shrubs. Plants die to the ground each fall after the red-leafed show ends. Kochia produces barely noticeable green flowers from spring through summer that results in its prolific seed supply. When the plant dries, it breaks off and rolls like a tumbleweed, dropping seed as it goes.
Kochia is unrelated to another bright-red fall plant nicknamed “burning bush” that is a winter-hardy woody shrub. Also known as winged euonymus (Euonymus alatus), that burning bush is another invasive seeder throughout most of the United States.
In the spring, kochia produces small, white flowers that break off and roll.
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Already-sprouted kochia plants can be pulled, cut, or sprayed with herbicides, ideally before plants have had a chance to produce mature seeds in summer. However, kochia reportedly is becoming resistant to some post-germination herbicides.
Because most kochia seeds live only a year in the ground, it’s an ideal weed to stop by applying a weed preventer such as Preen Extended Control in early spring. This granular product can be watered in over the top of existing and mulched beds for up to six months’ worth of control of new kochia. Make sure that before you apply Preen, you remove all other weeds in the area as well. Remember - Preen is a weed preventer, not a weed killer, so it is important to remove all signs of weeds before applying.