Seek and destroy now to halt full-on invasion

February 27, 2013 

The end of February is all about the weeds. The start of longer days and warmer weather means that annual weeds will be sprouting up anyplace they can find open ground, and early spring is the time to get control and become a first-responder to this attack. Here are the weeds you should seek — and destroy.

HORSETAIL AND MORNING GLORY: DEMON WEEDS

These two weeds cause so much frustration because homeowners make the mistake of trying to hand-pull these well-rooted invaders. Don’t be tugging at either horsetail or morning glory vines. Both these demons have survivor skills that tell the weed to send out new underground roots if somebody starts tugging at the top growth. Instead of stimulating the root system with a tug, sharpen up and cut back these weeds to ground level. Yes, they will resprout and grow more top growth. Then you’ll have to cut again to ground level and then in a month or two cut back the fresh growth once again. It often takes three cuts over three months to weaken the extensive root system and get control of these weeds.

Using Roundup or other herbicides on these two demon weeds will fail because the foliage of horsetail is so thin and made up of scales that won’t hold onto the poison and the leaves of morning glory have a waxy covering that can also resist herbicide sprays. Constant cutting of the top growth is tedious, but the most practical approach.

SHOT WEED

March right out and take aim now. Shot weed is the white flowering, low growing little weed with green leaves arranged in a circular whirl around the central flower stalk. It got its name for the way it shoots its seed, machine gun style all over the garden. The irritating fact is that this is a recent introduction to Western Washington gardens, brought into our area from nursery flats and potted plants.

First Line of Defense: Check all new plants especially the drainage holes of pots for this hitchhiking weed that sneaks into gardens by hiding under the foliage of plants that you bring home from the nursery. Next, check the cracks of the sidewalks, seams of cement walkways and damp, gravel areas for shot weed colonies. This weed loves damp, cool soil and when the seeds shoot about the garden, they can land in the most unlikely places. Shot weed will even multiply and go to seed in roof gutters and garden walls.

SMOTHER POWER

Hand-weeding an infestation of shot weed is a tedious and wet job in early spring, but even weed-killing herbicides will not stop shot weed this early in the year. The most practical approach is to smother large colonies of shot weed with sheets of damp newspaper. Local newspapers that run a garden column are the best form of organic weed block. In pathways and other areas where you will not be adding plants you can use cardboard, old carpet scraps or any heavy material that blocks out sunlight to smother the shot weed. In garden beds cover the newsprint with a fresh layer of bark chips, moo doo or other organic mulch and you’ll be improving the soil while you suffocate the weeds.

BUTTERCUP

The cheery yellow flowers that bloom in damp lawns across Western Washington are invasive buttercup and they are trying to tell you that your soil needs lime. This weed thrives in damp, acidic soil so don’t waste your money on weed and feed, or try to spray your lawn with broad leaf weed killers. Instead, improve the drainage by aerating and adding a topdressing of sandy loam to the old lawn right on top of the grass. An inch of loam will block light from the buttercup and weaken the weeds while the old lawn can push up through the new soil. Follow instructions on the label for applying dolomite lime or “Soil Sweet” as lime will change the pH or acidity of the soil slowly over time and too much lime can damage the soil structure. As an added bonus, soils that drain slowly with a lot of clay will begin to loosen up and become easier to work after proper applications of lime.

SLUG ALERT

The end of February and the beginning of March is also when you see the first blooms of yellow sunshine in the form of bright gold forsythia and cheery yellow daffodils. Let the color yellow be your warning light: The slugs are now awake and about. You’ll need to be proactive and make the first strike if you want to protect newly emerging lettuce seedlings or spring-blooming pansies. You also may need to sprinkle slug bait near flowering bulbs.

Marianne Binetti has a degree in horticulture from Washington State University and is the author of several books. For gardening questions, write to her at P.O. Box 872, Enumclaw, WA 98022. Send a self-addressed stamped envelope for a personal reply. She also can be reached at her website, binettigarden.com.

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