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Ferguson Caras LLC
989 Herrick Brook Road
Pawlet, VT 05761

If the Forsythia Already Bloomed,
Is it Too Late To Use Garden Weed Pre-Emergent?

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(This image is in the Souther Gallery.
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The unusually early spring has thrown many plants – and gardeners – into confusion. The forsythia’s blooms arrived four to six weeks ahead of the norm, as did migrating birds and the spring song of chorus frogs.

Most plants had no trouble weathering the whacky weather, including garden weeds. But with so much growth so early, many gardeners are confused about whether it’s now too late to apply pre-emergent to stop garden weed seeds from germinating.

Forsythia’s yellow flowers are definitely the flag drop announcing the start of weed-growing season, but, remember, it marks the optimal time to start, not the only time. If you miss that early weed prevention window, don’t throw in the towel. Starting early stops the earliest weed seeds from rooting, but different weeds germinate at different times all season long, so just start when you can.

Pre-emergents stop weeds by interrupting cell replication in root hairs. No roots means no weeds. In spring, one of the earliest weeds to sprout is crabgrass. Crabgrass seeds generally begin to sprout at the same time local forsythia bushes reach full bloom. This phenological phenomenon has been tracked over the years by university weed management researchers. This information is particularly important in lawn care, where stopping crabgrass in turf is a major concern.

In gardens, where soil is more exposed and vulnerable than in turf grass areas, the weed season can feature a more varied cast of intruders. Crabgrass is just the first of many weeds that plague gardens. In the top layer of garden soil, literally tens of thousands of dormant weed seeds lie ready to grow, spring through fall, when conditions are conducive. Thus, logically, while early is optimal, it’s never too late to apply pre-emergent.

A weed preventer such as Preen prevents new weeds, it doesn’t kill ones that are already growing. For gardeners wishing to minimize hours lost to weeding: first, pull or dig out existing weeds, ideally while they’re young and easy to pluck and, definitely, before they go to seed! Then apply weed preventer granules atop garden soil or mulch to create a weed-barrier that stops weed seeds from germinating for up to three to four months. The barrier will also stop any seeds exposed by soil disruption caused by pulling weeds, plus stop new seeds carried in by the wind, birds or animals during that period. Why let weeds take root when you can stop them from ever happening?


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