Know Your Enemy In Weed War

Which weeds in your garden give you the most trouble? For me, it’s quackgrass. Running a close second is morning glory followed by fern horsetail, Canadian thistle and groundsel. This sounds a bit like a horse race, only there are no long shots. Any one of these noxious weeds could take over my yard in a snap. But not this year.

For the past week, I’ve been on my knees tugging and yanking these foul intruders. My hands are so sore, making a fist is out of the question. When I close my eyes, the outline of a weed emerges. And to add to this misery, when I finally make it all the way around this landscaped acre, their offspring will be waiting for me.

You, too, may have stumbled over these monsters in your garden. You may call them by different names, even some names that may not be printable. Here are details on my least-favorite weeds:

Quackgrass: It can invade a lawn overnight, throwing up wide blades of grass several inches taller then the existing lawn. It can invade shrubs, groundcovers, flower beds and vegetable gardens, all seemingly from one plant.

If you’re lucky, that fist full of grass blades you just pulled up will remain attached to a long, white underground root called a rhizome. It may lead you under, around and through the beds, picking up attached family members all along the way.

Normally, however, the root snaps and you’re left holding a fist full of blades, a short dangling root and the promise of a field of healthy quackgrass to come. For if one small segment of root is left behind, count on encountering dozens of wide, flat, pointed blades of grass tomorrow.

Mechanical controls may not be the most effective. The best control for quackgrass is to kill it out with the non-selective herbicide, glyphosate, found in products such as Roundup or Finale. Of course these products CAN NOT BE USED ON THE LAWN. Non-selective means it will kill or damage anything that is green.

However, if you are careful, you can paint or sponge the material onto the quackgrass, keeping it off the desirable plant. Though it’s easier to remove once it’s dead, it’s still a grass with stubborn roots that may not want to give up their hold.

Since non-selective herbicides are so difficult to use around your lawn, shrubs and flowers, the quackgrass may be your companion for years to come. You can see why it’s on top of the most-hated list.

Morning glory (field bindweed): This perennial entwines itself onto any plant in its path, making it very frustrating to deal with. Its stems can grow from 1 to 4 feet long, creating a dense tangled mass that is difficult to dislodge. After a bout of pulling and a few short words, the hostage plant is freed, but usually not without showing a few battle scars. Many a rose blossom has found itself on the ground before its time.

If the choking vines aren’t enough, consider this - it’s roots can dive 10 feet into the ground while sprouting long lateral roots. If that doesn’t set you back, seeds can remain viable for up to 50 years.

How do we control this one? It’s difficult to use glyphosate (Roundup) since morning glory engulfs the desirable plant. If you spray it while it’s young, before it starts its climb, you can achieve some control.

Pulling and tilling only encourages new plants. If you wish control of this plant, you must be on it at all times. It can become a groping mass of stems overnight.

Field horsetail and Smooth scouringrush horsetail (jointgrass): Now these two plants are definitely a problem. This stuff was around with the dinosaurs. Field horsetail is soft with many whorls of slender, green jointed branches. It grows quite nicely in moist soil such as my rose garden and lawn. Though touted as a high water table plant, I have found that it also grows quite nicely on my neighbor’s arid driveway.

Smooth scouringrush on the other hand, has stems that are tall, slender, hollow and jointed. This horsetail prefers dry soil, though it, too, will survive in moist areas. The reason they do so well? Both have roots that go to China.

I introduced field horsetail into our garden from a container-grown dogwood tree 18 years ago. That’s how long I’ve been dealing with this problem. This is one reason why it’s so important to wash roots of plants dug from friends’ gardens. Hidden surprises like noxious weeds and insects can easily accompany incoming root systems. Also, once in a while, nasty plants even slip by in nursery stock.

The pre-emergence Casoron is the only chemical I’ve found that seems to keep this noxious fellow at bay. The only problem is, Casoron is only listed for use around woody stemmed plants such as roses, trees, shrubs, etc. It cannot be used in perennial or annual flower beds or the vegetable garden.

Canadian thistle: I think I have this one finally under control, although I still encounter groups of it in shrubs and in the lawn.

Canada thistle multiplies from seed or long horizontal underground roots. Ma, Pa and a passel of youngun’s can be hooked onto the same root. If you till or cut the root, a whole new clan will come a callin’.

This thorny plant can be controlled with Roundup especially if caught at a young age. Once it’s growing, Roundup only seems to kill the top of the plant, leaving the root quite viable for another generation.

Common Groundsel: The only reason I list this plant, is that it is so prolific. Although it has a taproot, it is relatively easy to pull. It’s easily identified by its green, sharply notched leaves and yellow disk flowers. The problem is, it can go to seed at anytime in its life. It can be a couple inches tall and go to seed or 18 inches tall and go to seed. Either way, you clean the bed of these rascals, and low and behold, they’re back the next day.

These are only my top five. There are a number of others I could have added to the list. I certainly didn’t mean to short-change anyone. But for now, it’s back to the good earth. That’s optimistic since right now, I don’t see much of that through the weeds.

Upcoming events

Sunday is Rose Hill Day at Manito Park. From 4 to 8 p.m., the Spokane Rose Society’s consulting rosarians will be on hand to answer all your rose-related questions. This is also your chance to see the new AARS rose selections for 1999.

The Cherry Pickers Trot and Pit Spit will be held at Greenbluff Thursday evening. The event includes a fun run, the pit-spit competition, plenty of cherry-related goodies to eat and, of course, cherries by the bag-full.

The Inland Empire Gardeners are sponsoring a “Summer Garden Carnival” July 18. The event’s designed for gardeners and non-gardeners of all ages. I will pass along more information on this event next week.