Written on April 26, 2013 at 10:40 am , by Eric Liskey
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.