Gardener’s Notebook: Quashing quackgrass

My foe is quackgrass, also known as witchgrass, couchgrass and, botanically, Elytrigia repens. It is small consolation that quackgrass isn’t only my problem; this native of Europe, North Africa and parts of Asia and the Arctic is now a worldwide weed. (NYS IPM Program at Cornell University)

My foe is quackgrass, also known as witchgrass, couchgrass and, botanically, Elytrigia repens. It is small consolation that quackgrass isn’t only my problem; this native of Europe, North Africa and parts of Asia and the Arctic is now a worldwide weed. (NYS IPM Program at Cornell University)

My first garden foe, which I haven’t seen for years, recently sneaked into the greenhouse. Damping-off sounds pretty bad, but not as bad as its scientific names: probably Rhizoctonia or Pythium, which, along with a few other fungi, can cause damping-off.

My introduction to damping-off disease came before my first plants even made it out to my first adult garden. At the time, I was living in a relatively dark apartment – a converted motel room – and was eager to start seedlings. I sowed all sorts of seeds in peat pots, stood them in a little water, then crowded them together on all the shelf space that could be mustered.

Young sprouts never appeared in some of the pots. In others, seedlings emerged, then toppled over, their “ankles” reduced to a withered string of rotted cells, unable to support the small plants physically or physiologically.

Conditions created were perfect for any one of the damping-off culprits: overly wet soil, cool temperatures, low light, weak growth, stagnant air. How was I, a beginning gardener, to know? I soon learned to avoid the disease by, in addition to providing good light, providing sufficient fertility to promote strong growth that resists disease; paying careful attention to watering; and using a fan to keep air moving.

My seeds now go into a potting mix containing sufficient perlite to help drain away excess water. Sterile potting mixes, such a those sold bagged, are presumably free of damping-off culprits. But sterile mixes also lack beneficial soil microorganisms, so afford free rein to any culprits that make their way into a mix. My homemade potting mix isn’t sterilized.

A couple of other tricks also limit damping-off disease. Spreading a thin layer of dry material such as perlite, vermiculite, sand or kitty litter (calcined montmorillonite clay) on the surface of the potting mix keeps the stem area dry. And there is some evidence that chamomile tea (cooled) controls damping-off disease if sprayed on plants and the soil surface.

I’m considering this most recent damping-off incident to be a fluke, so far affecting just a single cabbage plant in a whole flat of cabbages.

That first garden – my first garden – was short-lived, not because of any horticultural trauma, but because it was begun on August 1 and, before the following year’s gardening season got underway, I had moved. My new site, home to my second adult garden, was also home to my second garden foe, which has been lurking in the wings of every garden ever since then.

That foe is and was quackgrass, also known as witchgrass, couchgrass and, botanically, Elytrigia repens. It is small consolation that quackgrass isn’t only my problem; this native of Europe, North Africa and parts of Asia and the Arctic is now a worldwide weed.

Soon after turning over the soil to begin that second garden, quackgrass invaded – with a vengeance. Long story short: I had read of the benefits of mulches in smothering weeds. In Wisconsin, where I lived, lakes were becoming clogged with water weeds, which municipalities harvested; I convinced a water-weed crew to dump a truckload of water weeds on my front lawn. My quackgrass expired beneath a slurpy mulch of quackgrass laid atop the ground pitchfork by pitchfork.

Quackgrass has always stalked the edges of my gardens, waiting for a chance to slink in. It spreads mostly by underground rhizomes, which are modified stems that creep just beneath the surface of the ground. Growing tips of quackgrass rhizomes are pointed and sharp enough to penetrate a potato. Given time, quackgrass develops an underground lacework of rhizomes.

My current garden never had a quackgrass problem, mostly because I never tilled it or turned over the soil. Tilling or hand-digging it, as I did in my second garden, compounds quackgrass problems because each piece of rhizome can grow into a whole new plant.

My current hotspot of quackgrass found a fortuitous opening, creeping in amongst a planting of coral bells beneath a very thorny rosebush along the edge of my vegetable garden. Quackgrass rhizomes must be removed or the quackgrass smothered: either difficult to do among the coral bells and the rose.

My plan is to sacrifice the coral bells and pull out every rhizome that I can find. In soft soil this time of year, long pieces can be lifted with minimum breakage or soil disturbance. A mulch with a few layers of newspaper, topped with a wood-chip mulch (part of weed management, as described in my book Weedless Gardening) will suffocate any overlooked rhizome pieces trying to sprout. In the absence of other plants among which the rhizomes could sprout, mulching alone can do in quackgrass, as it did in my second garden.

Longer-term, barriers around garden edges could prevent quackgrass rhizome entry. Barriers need to be deep or wide. A concrete strip, six inches wide and decoratively inlaid with handmade tiles, has been effective elsewhere along my garden edge.

For now, I have to stop writing and get to work on the quackgrass.

 

Any gardening questions? E-mail Lee at [email protected] and he’ll try answering them directly or in his Almanac Weekly column. To read Lee’s previous “Gardener’s Notebook” columns, visit our website at HudsonValleyAlmanacWeekly.com.

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