This will be a summer to remember. We may not have appreciated the heat, but the weeds have been delighted with it. I have heard a great deal of moaning about spotted spruge, purslane and even crabgrass. Even if people applied a pre-emergent in a timely manner, the crabgrass has flourished especially in fescue lawns that were damaged by the June heat. The good news is that the temperatures are cooler, maybe the smoke is gone, and it is time to get back to gardening.
Just as autumn is the best time to plant trees, shrubs and spring-blooming bulbs, it is the best time to weed. Oh, don’t whine! I know you have been pulling annual weeds all summer. Now is the time to attack perennial weeds. You will be able to beat them back. The weather is pleasant, and the soil is warm. Remember that the soil and the weather are cold in March.
So what are the target plants? Start with the toughies, Field Bind Weed/wild morning glory (Convolvulus sp.) and Horsetail (Equisetum sp.). Both of these weed have massive root systems that are difficult to eradicate by pulling and digging. Herbicide painted on the stems and leaves of the plant at this time of year is effective because the product is carried down to the storage roots. If you treat the weeds this fall, again when they show up in the spring and then again next fall, you will have weakened the plants so much that you will have prevailed. Yes!
Then there are the perennial nuisance weeds. Everyone has a favorite one to hate. My nemesis is quackgrass or couch grass (Elymus repens). It just creeps in the dark of the night, I think. How satisfying to dig out the long, white roots, but you can’t leave any bits. This weed also responds to painted herbicide, but because its roots curl around your desirable plants’ roots, the herbicide can cause some collateral damage. It is best to just get down on your knees and dig it.
Dandelions (Taraxacum) were brought to America by the pilgrims and other early settlers to eat in the early spring. They are one of the first greens, and people needed greens in their diets after a winter of salted fish and beef and stored root vegetables. Many people have more dandelions in their lawns than they could possibly eat. Some people use herbicides to eliminate the plants during the growing season. In the fall the plants are easy to dig and the long tap root slips out of the soil. False dandelion, also called Spotted Cat’s Ear (Hypochaeris radicata), grows in lawns that have poor soil fertility, compaction and minimal water. Perhaps this weed is trying to tell you something about lawn care in that area of your yard.
Other weeds such as Wood Sorrel/Oxalis/Wild Shamrock, Spotted Spurge, Black Medic and Purslane are annual weeds. They are dealt with in the spring with either a pre-emergent herbicide applied at the correct time or by pulling. Or spray them with 20% vinegar before they produce seed. Best of all, this autumn apply a layer of mulch on your flowerbeds so the weed seeds cannot find the light to germinate.
Don’t forget to deal with real “baddies” such as Russian thistle and the knapweeds before they distribute their seeds. These are annuals or biennials, and you can begin to control them by cutting the weed to the ground and stuffing the stems and seeds into the trash.
Enjoy the fall sunshine, and get out there and weed!
A WSU Master Gardeners of Chelan County column appears weekly in The Wenatchee World. Bonnie Orr is one of four columnists featured. To learn more, visit wwrld.us/cdmg or call (509) 667-6540.