Winning the war on weeds: Even garden peaceniks sometimes go nuclear

These days, gardening is all about tolerance. Instead of zapping weeds with herbicides, homeowners dine on purslane and plantain, and leave flowering dandelions for the bees. On gardening websites, people who seek help identifying weeds are airily dismissed as not only ignorant but prejudiced.

"A weed is just a plant in the wrong place," the tongue-cluckers write, verbally wagging their fingers at the questioners.

I'm all for peace and co-existence in the garden. There are many things gardeners can do before pulling out heavy ammunition like herbicides to correct a problem that might have been prevented with planning, site preparation and a little well-timed exertion.

Still, stuff happens. A bird drops a seed, and before you know it quackgrass is romping through the daylilies. Creeping bellflower, a mysterious invader with deceptively pretty flowers that suddenly appeared in my neighborhood about 15 years ago, is now marching through almost every front-yard garden I walk past.

To me, the wily ways of quackgrass and creeping bellflower make Minnesotans' most-hated weed — creeping Charlie — look like a pipsqueak. Vigilant gardeners can pull a string of creeping Charlie up by hand and get most of the plant. But quackgrass and creeping bellflower are almost impossible to eradicate on the first try.

While creeping Charlie will sprout a new plant if you leave a broken piece behind, it grows on the surface of the soil, so you have a better chance of being able to remove it by weeding.

Not so with creeping bellflower and quackgrass.

Both have roots that defy weeders. Quackgrass has a creeping underground rhizome, a kind of horizontal white root that sends up new plants inches or feet away from the parent. Quackgrass is most easily pulled by hand early in spring. But leave one tiny segment of rhizome behind, and a new plant springs up.

According to the University of Minnesota Extension Service, quackgrass rhizomes can pierce potato tubers and pop through asphalt. One plant can produce 300 feet of rhizomes in a year!

Creeping bellflower (Campanula rapunculoides), a European native that was introduced to this country, looks a bit like native campanulas but is far more aggressive. It has a fat root like a little carrot, as well as shallow fibrous roots that, left behind, become new plants.

Many websites recommend digging at least 6 inches deep around creeping bellflower in a circle several inches away from the stem. But while hand-digging can set the plant back, it rarely eliminates it.

And now we come to the unhappy conclusion that for these two aggressive weeds, the best control is through chemical means.

While I consider myself a garden peacenik, the one plant I break my no-chemicals rule for is creeping bellflower. Each spring I dig up the offending plants as well as I can and then keep a sharp watch for any rebounding babies. And when they appear, as they inevitably do, I break out the glyphosate (the main ingredient in Roundup), do spot treatments on individual plants and hope for the best.

Usually it takes at least two applications a couple of weeks apart to kill the plant. But where creeping bellflower is concerned, "kill" is a relative term. New plants always pop up by the end of the summer, and each spring the battle begins anew.

If you decide to go the glyphosate route, remember that it will kill anything with leaves, and should be applied with care.

As for quackgrass getting into the daylilies, it's happened this year in my own garden. Although I've been vigilant in previous years about pulling the odd strand of quackgrass, it hasn't worked because bits of rhizome remained. This year I have a real problem in one daylily bed. My plan is to dig up all the daylilies — there are perhaps 15 clumps — and untangle the quackgrass rhizomes from daylily roots as best I can. If the weed dares to pop up again, as I'm sure it will, I'll have to decide whether to keep pulling the quackgrass or use the nuclear option.

I hope I don't have to do that. But sometimes, idealism yields to practicality. It's me or the garden thugs, and in this case I want my gardens to be the winners.

Here are links to some useful sites that can give guidance on dealing with quackgrass and creeping bellflower:

http://tinyurl.com/obtqfvm

www.minnesotawildflowers.info/flower/creeping-bellflower