Spring 2002

Weeds and Nature

Are we looking at the richness of nature? Or just a patch of weeds?

Yellow dandelions, of course, are classic yard weeds. And they’re not even the weediest plants in this picture. The fuzzy dried grass plume lying across a slab of fallen bark is the seed head of foxtail grass. An alien annual, foxtail pops up only where recent disturbance has left a patch of bare soil in bright sun. If this spot is left alone, the perennial dandelions and violets will soon crowd out the foxtail.

Some folks treasure violets in their lawns. Others poison them or dig them out. Fritillary caterpillars eat only violet leaves. If you find a fritillary chrysalis in your violet-filled lawn (as I did), it means that a butterfly thought your yard looked like nature to her, and honored it with an egg.

The common blue violet is something of a "native weed." It grows in savannas and woods, but it’s most common in disturbed areas. A strong competitor, it should long outlast the dandelions here — and perhaps rear some fritillaries.

The only other plants in this photo are young cherry trees. Both the cherries and the bark fragments suggest that there are branches overhead. Cherries disperse their seeds mostly in the bellies of birds, which thoughtfully deposit them beneath comfortable tree perches.

Thus, apparently, the forces of weedy nature are hard at work here. But what will happen to this plot? If this patch of ground is part of a forest preserve where restoration is under way, then rich savanna and woodland will slowly emerge. Some of the violets and the cherries would have a permanent home. So would the fritillaries and hundreds of other rare species.

But many studies have shown that the oak savannas and oak-hickory forests of Chicago Wilderness are fading out. The keystone trees are being replaced by invasives like European buckthorn, wild cherry, and maples. Oak forests are open sunny scenes, full of beauty and wildlife. Conservation agencies conduct prescribed burns and thin some species of invader trees to save ancient natural forests that have become rich with rare nature over the millennia.

If this patch is just left alone, the growing cherry trees will probably shade out the violets (and the fritillaries). In time, buckthorn and maple will then probably shade out the cherry. But no one really knows, since these invader forests are a new phenomenon.

There is much to appreciate in treasured wild yards and in untended forests of invasive trees. But these days, rare nature requires good stewardship. Saving the full richness of creation, especially the parts that need our help, is what Chicago Wilderness is all about.

Flower photo by Willard Clay. Chrysalis of the variegated fritillary by Ron Nelson. Words by Stephen Packard.