Good Weeds

Image Gallery M.P.L. FOGDEN/BRUCE COLEMAN. INC

Gardener, hold that hoe!

Those wild volunteers do have their good points.

In 1879, botanist William Beal decided to see how long weed seeds could remain viable. He buried 20 jars, each filled with 1,000 seeds. Then, every five years, he dug up a jar and planted its contents to see which kernels would still sprout. After he died in 1924, colleagues continued the work. In 1979, they watched some 100-year-old seeds germinate.

Add longevity to productivity (some weed plants can produce as many as 40,000 seeds), and you'll realize why, left unchecked, weeds will usually outcompete your garden vegetables for sunlight, nutrients and water. No wonder most gardeners have earned the weeder's merit badges of Calloused Palm and Hoe-er's Hunchback.

But weeds do have their good side. Under controlled circumstances, many of them can greatly benefit our gardens. They hold top-soil, pull up water and nutrients, provide food, help control insects and more.

Then too, we often don't make the association between the beautiful wildflowers that erupt around us from spring through fall and the fact that most of them bloom on otherwise ordinary weeds. We should. To do otherwise would be like admiring butterflies but hating caterpillars.

So yes, for beauty and utility, weeds do have their good points. You'll probably always hack away at ones that crowd your crops. But when you think about all the good they can do, maybe you'll see them with a more benevolent eye, and selectively use those volunteer visitors to your garden's advantage.

Holding Topsoil

When we get cut, a scab forms to protect the injured spot while it's healing. In the same way, weeds bandage the earth— moving in fast wherever there's bare soil. (Any gardener can attest to that!) This is nature's way of ensuring that valuable topsoil won't be washed or blown away. Indeed, weeds have saved incalculable amounts of this precious fertile earth from erosion—and with little thanks from us.

So if you have an idle garden area that's coming up in weeds, consider them a free cover crop. True, if the invader is toxic (like poison ivy), a tough grass (like Johnson grass) or a perennial that spreads by underground runners (like sheep sorrel), you will want to root it out. But why not let nonspreading annuals like spurges, purslane, lamb's-quarters, chickweed and ragweed anchor that fallow ground?

WEEDS AS SOIL INDICATORS

Acid soil: Ox-eye daisy (Chrysanthemum leucanthemum), curly dock (Rumex crispus), sheep sorrel (Rumex acetosella), sow thistle (Sonchus species), prostrate knotweed (Poly-gonum aviculare), lady's-thumb (Polygonum persicaria), wild strawberries (Fragaria species), plantain (Plantago major), rough cinquefoil (Potentilla monspeliensis), silvery cinquefoil (Potentilla argentea), hawkweeds (Hieracium aurantiacum and pratense), knapweeds (Centaurea species).