Tuesday, January 4, 2011


            I have a love/hate relationship with weeds.
Poa annua
Annual bluegrass

On the one hand, you have to admire their indomitable tenacity in the face of intensive cultivation. Their ability to assume the habit and color of the plant whose water and nutrients they're stealing intrigues me. Who knew plants could manage camouflage? Weeds also often produce flowers of startling delicacy and loveliness.

On the other hand, they siphon resources that gardeners prefer be dedicated to the exclusive use of the planted plants, which is, at base, what defines a weed.

Aphorisms about weeds abound. “A weed is just a plant in the wrong place,” according to some wags. Others maintain something like “A weed by any other name is a native plant.” True enough, but oh, puh-leeze. “Weeds are in the eye of the beholder” is another one. It makes sense that “One gardener’s weed is another gardener’s treasure”: some plants I wouldn’t have in my yard on a bet are sold in other parts of the country as valuable garden additions—showy evening primrose (Oenothera speciosa), Virginia creeper, Smilax (otherwise known as pernicious cat briar), purslane, Dichondra and mullein, to name a few. As a child, my favorite flowers—I gathered great fistfuls of them for my mom—were fuzzy purple henbit blooms, sweet-smelling white or pink globes of clover, and pungent dandelions. Even now I love to see great sweeps of blue-blooming oldfield toadflax and red sorrel in fallow fields. 

Capsella bursa-pastoris

That doesn’t mean I welcome them in my yard.

            On the southeastern coast, mild winters ensure two crops of annual weeds a year—the cool-season ones and the warm-season ones. Chickweeds (oh, yes, there are several), annual bluegrass, sow thistles, oldfield toadflax, shepherdspurse, Carolina cranesbill and blue-eyed grass start appearing in late fall and persist until the ground warms up. Crabgrass, poorjoe, bindweed, Florida pusley, sand spurs, sesbanias, chamberbitter and the whole spurge clan show up as the winter weeds begin to fade, and don’t give up until soil temperatures drop again. The thing all these thorns-in-our-sides have in common is that they reproduce by seeds dropped as they die. Ergo, pulling them before or just as they start to flower is crucial to reducing populations. You won’t ever get them all, but vigilance does pay off.

You should also know that some weed seeds can lie dormant in the soil for decades. Every time dirt gets disturbed, new weeds sprout. Isn’t nature marvelous?

Stellaria media
Common chickweed
Southeasterners also get separate crops of warm- and cool-season perennial weeds each year. Examples include creeping and yellow woodsorrels, Florida betony, cool-weather and warm-weather sedges, fleabane, dog fennel, common vetch, threeflower beggarweed, broadleaf plantain (not the banana relative) and the dreaded pennywort. Viney perennials include Virginia creeper, cat briar, kudzu and, most feared of all, poison ivy, oak and sumac. Most spread by rhizomes; all are difficult to eliminate. The tiniest bit of plant left behind in the soil regenerates—rather like the dragon’s teeth of myth—into 15 new plants by the following season. Or, if you're talking Florida betony and pennywort, by the following week. Still, if you keep pulling and pulling and pulling the top-growth, photosynthetic processes falter, and eventually even cat briar starves to death.

Top: Gnaphalium spicatum
Shiny cudweed
Bottom: Stellaria media
Common chickweed

Sometimes plants not normally considered weeds elbow their way into the category, like Coreopsis grandiflora. The lovely golden-yellow daisy flowers of the four plants I idiotically put in my small garden delighted me their first season with a long and prolific bloom time. What I wasn’t to know until the following spring is that coreopsis seeds have about a 130% germination rate. For the next five years, I pulled up thousands of seedlings, all over my yard and the neighbors’. Other herbaceous plants to keep a close watch on include bee balm (Monarda spp.), passionflower vine (Passiflora incarnata) and Texas or hardy ageratum (Eupatorium coelestinum), a single plant of which turned nightmarishly thuggish in my garden.

Some woodies also spawn unwanted seedlings and suckers: heavenly bamboo (Nandina domestica, considered invasive in Florida, like almost everything else), crape myrtle, wax myrtle, wisteria, pine trees and oaks (squirrels get most of the credit for these last). Deal with these pseudo-weeds the same way as the more traditional ones: pull, pull, pull.

Lamium amplexicaule
 Now, I’ve used the names of several common weeds in the preceding paragraphs. I know what they look like, foliage, flowers and roots. I bet many of you don’t. I wouldn’t want to hang from a rope of poison ivy while you decided if a specimen might be a woodsorrel, a henbit, a threeflower beggarweed or that enormously expensive designer perennial you planted last fall. Tim and I often hear the plaintive refrain, “I didn’t know if it was a weed or not.” Well, I don’t always know, either. Ignorance gives us two choices: 1) let the thing grow to the point where you can identify it as something you planted (or not), usually when it flowers; or 2) pull it out and then watch to see if something you may have planted in or around that spot comes up (or not). I usually opt for the former tactic, because I rearrange my garden so regularly that, despite my garden journal and the little maps I draw (but fail to update), more often than not any given seedling’s provenance is a mystery. 

Pyrrhopappus carolinianus
Carolina falsedandelion
  You’ll notice I haven’t mentioned herbicides as away to get rid of weeds. That’s because I won’t use them. I also understand that you aren't me. But please, go easy on the Roundup and the brush killer, okay? Instead, spend a little quality time out in your garden when the ground is dampish, removing the buggers by hand. Target the ones with flowers, as you really don’t want seed for next year’s crop to ripen and fall. As a card-carrying anti-sprayite, I also weed our lawn by hand, which means we have a lot of creeping sorrel, spurges, sedges and the occasional sandspur in the grass. But that’s okay. I consider it acceptable damage, and it pleases me not to be pouring glyphosate or worse into the ocean.
Gnaphalium pennsylvanicum
Wandering cudweed

Speaking of herbicides, a disturbing phenomenon has been noted by the people whose business it is to notice such things. Some weeds have developed resistance to herbicides in the same way some insects have evolved tolerances for common insecticides. This situation arises through pesticide overuse, in the same way human superbugs come from overprescribed antibiotics. Don’t get me started on Monsanto, DuPont and the “better living through chemistry” boys engineering mutant corn and soybeans with genetic resistance to weed killers. Why? So field crops survive blanket-sprayed herbicides. So now, in addition to unknowingly consuming genetically altered food, we can ingest massive doses of glyphosates too! 

Sonchus asper
Spiny sowthistle

So please—for your sake, for my sake, for the planet’s sake—think very hard before you spray anything. And before buying anything produced by Monsanto, DuPont, Dow Agrichemical, Bayer Crop Science, etc., etc., etc.

            You probably will not be too astounded to learn that I actually enjoy weeding. I like the intimacy of it, the deep satisfaction engendered by teasing out a particularly long runner of pennywort, the thrill of tugging out a threeflower beggarweed with its taproot intact.

            Hand-weeding is my way of giving the plants I’ve chosen first dibs on available water and nutrients. It is also one of the very few activities resulting in instant gratification in the gardening world.

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Thanks for dropping by. See you next time.