In the Garden | Arbor Day tree and shrub distribution is April 13

Bonnie Orr, master gardener

These are some of the non-factual weed myths Master Gardeners often hear:

Weeds are plants that thrive in places you wish they did not grow. Weeds are often native plants; sometimes they are plants introduced to the area by accident, such as knapweed or puncture vine. Sometimes the plants were introduced deliberately because of their health benefits and then ran amok: Consider dandelions, which the Pilgrims brought in 1621.

This is the time of year to deal with weeds in the flowerbeds and the vegetable garden. Broadleaf plants grow in these places, so the herbicides used on lawns can’t be used. So what alternatives work?

Let’s consider annual weeds first. The seeds may have blown in or may have been carried by a bird or your dogs or your walking shoes. Annual weeds are easy to deal with. They can be plucked from the ground while young because the roots are very feeble. They can be scraped off the ground. They should never be dug out because digging in the soil exposes more weed seeds to the light they require to germinate. Eliminate these weeds before they flower and go to seed. They often only have to live a few weeks before setting seed, then your weeding job has become more tedious. Because they are easy to deal with, chemical herbicides are not needed. The most effective means of preventing annual weeds is to use 3 inches of mulch between flowers or vegetables.

Perennial weeds, such as dandelion or salsify, have deep tap roots that need to be twisted out of the soil. Worse, field bind weed or horse tail have large, long storage roots. These weeds need to be dug to gather up as much of the root as possible. Taking out the perennial weeds before they flower is important. Have you ever pulled a dandelion plant and then dropped it on the ground? Three hours later when you walk by to pick it up, you will notice that it has set seeds even though it never bloomed. Gather perennial weeds in a black plastic bag. When it is full, tie it off and set it in a hot place for 10 days. Then empty the decaying material into your compost pile. The weeds seeds will have been cooked if the temperatures have been high enough.

A biennial is a weed that grows leaves — usually flat on the ground — the first spring, and then produces flowers and seeds the second spring. The trick is to pull out the rosettes, the flat leaves, and the roots the first year. You will recognize this pattern with knapweeds or mullein. The rosette can go directly into the compost pile.

Now, the biggest scourge of all: perennial grasses. Herbicides are often effective because the grasses have extensive roots. These grasses, such as quack grass with a “mile-long” root that has lots of off shoots, can be killed. But the application must be done with care so the flowering plants and vegetables are not affected by the herbicide. Don’t confuse the annual grasses with their wimpy roots with the perennial grasses with aggressive roots.

People often mention how frustrating it is to weed, mostly when the weeds have gotten tall and gone to seed. Sometimes people moan that they had just weeded two weeks ago, and now there are weeds again. Sad to report, these are different weeds. You got rid of the first batch, but as the soil warms, different weed seeds germinate.

Weeding is a season-long process. The good news is if you weed now, and mulch to prevent the germination of annual weeds, you can create an environment where you only have to weed about three times during the entire growing season.

Visit the WSU Master Gardeners at 400 Washington St. on Mondays and Wednesdays from 1 to 4 p.m. They will identify your weeds and suggest ways of dealing with them.

A WSU Master Gardeners of Chelan County column appears weekly in The Wenatchee World. Bonnie Orr is one of four columnists featured.