This is the lone forsythia bush in my yard. Of course, the bright yellow blooms are an awesome, welcome sight in spring for gardeners hungry to get their hands dirty. But I have it there for another reason: it’s a “phenological indicator”. That’s what the geeks say, instead of just calling it a biological clock. It’s long been understood that plants and animals react in predictable ways to warmth, and you can use that fact to help time various gardening activities. In this case, you can use forsythia to time your weed preventer applications for lawns. Crabgrass seeds germinate just about the time forsythia blooms drop from the plant. And you need the weed preventer on the ground before the seeds begin to grow. Many other garden pests can be timed this way too. Check with your local cooperative extension office or master gardener program. They often can tell you when pests typically are active. Just take a look around your garden at those times, and make note of what’s in bloom. Chances are, that will serve as a good guide to when you should apply a controls.
The real reason this is so helpful is that you rarely see pests until it’s too late to control them (or control them easily). Once a borer is inside your cucumber vine, it’s too late. Once weed seeds have germinated, weed preventers are ineffective. So timing is everything.
Late August is prime time for crabgrass. The yellow green foliage and forked seed heads are especially evident in lawns browned out from hot, dry summer weather conditions.
However, late summer is not the time to control crabgrass. It’s an annual, and will die with the first frosts of fall. But prior to that, it will spread thousands of seeds ready to germinate next spring.
Last year the crabgrass got out of control in my yard, so I vowed to do something about it this year, despite the fact that my lawn is the poor stepchild of my garden. I admit that the perennial beds and shrub borders receive a lot more attention than my lawn. It’s hard not to play favorites! The lawn usually survives with periodic mowing, no fertilization, no watering, and spotty weed control. (I use a dandelion puller, and often hand weed the black medic and oxalis that pop up in the grass.)
This spring I agreed to try GreenView’s Crabgrass Control Plus Lawn Food. This slow-release fertilizer and crabgrass control combination is supposed to prevent crabgrass and many other annual weeds all season long, and has the benefit of slow-release fertilizer to promote sustained growth of grass. The time to apply the crabgrass preventer is in early spring before the soil warms to 50 degrees F, which is usually about the time that forsythias bloom.
I was pleased with the results. The grass in the lawn was thicker and greener than in the past, with no sudden flush of growth. And crabgrass has remained mostly under control. (In some of the worst sections, I saw some seedlings sprouting in mid-July, so I applied some corn gluten meal to those areas to prevent further sprouting of the crabgrass.) Since then, I’ve been easily able to keep up with hand weeding the occasional crabgrass seedling that pops up in the lawn.
This fall, I’ll apply the GreenView Fall Lawn Food to give the lawn a boost going into winter. And next year, I’m looking forward to a much-reduced crabgrass crop because I’ve been able to stop it dead in its tracks this year.