Parasitic plant makes even dandelions look friendly

If you think dandelions are bad weeds, just imagine a weed that doesn't even look like a plant, and whose tangle of pale yellow stems slowly envelop other plants like an insidious veil. You might wonder how a plant without chlorophyll can survive.

The plant is dodder, a parasitic plant that survives only by sucking the lifeblood out of another plant. You may know other parasitic plants. Mistletoe, for example, is one, but has green leaves so is only partially parasitic. Some orchids also are partially parasitic.

Dodder eventually kills a plant as it sucks out water, minerals, and sugars. And while dodder is doing its evil work, its inconspicuous flowers are making seeds for future wickedness. In the true tradition of any smart weed, not all the seeds will germinate at once. Some will germinate this season and others will wait until next year.

Another eerie thing about dodder: The germinating seed grows only a stem, no roots. The young stem flails around until it grabs onto a host plant, and then sends little pegs into the host through which to suck out food and water. Soon after the stem attaches to a host, the base of the dodder plant, now useless, shrivels and dies. The stems then continue to happily overrun their host, plugging in new feeding pegs at intervals. With good reason, dodder is also called strangleweed or devil's hair.

Dodder is present throughout the country but is at its worst in southern and north central states. Still, anywhere it's noticed, it should be weeded out quickly. Besides starving its host, dodder also can spread virus infections from diseased to healthy plants.