Yes. Oak is among the trees listed for Florel Fruit Eliminator, which keeps flowers from setting fruit when sprayed during the oak's spring bloom. On red oaks, the results take a year to show, because acorns already forming from the previous spring's flowers still mature and fall.

How does Florel keep acorns from forming?

By interrupting the step from flower to fruit. An oak produces its male and female flowers in spring, and Florel alters the hormonal signals that turn those flowers into fruit, so a sprayed flower never becomes an acorn. Each spray affects only that season's flowers.

When and how should an oak be sprayed with Florel?

At mid to full bloom, in mild weather. Spraying Florel Fruit Eliminator, mixed at about 3 ounces per gallon of water, onto an oak's flowers and foliage while temperatures sit between 65 and 95 degrees Fahrenheit keeps that spring's flowers from setting acorns. The spray wets the canopy without running off, and an oak stressed by drought, heat, or disease is left unsprayed.

Why do some oaks keep dropping acorns after spraying?

Because red oak acorns take about 18 months to mature. Acorns that began from the previous spring's flowers are already on the tree when the next spray is applied, so they still drop that fall, and white oaks can take one or two years depending on the species.

Frequently Asked Questions

Does the whole canopy need to be sprayed?

Yes. Good spray coverage is essential for complete fruit elimination, so branches the spray misses can still set acorns.

Do oaks drop more acorns in some years?

Yes. Acorn crops vary widely from year to year, with large quantities in mast years.

Can Florel be used on other trees with messy seeds or nuts?

Yes. Buckeye, horse chestnut, sweet gum, sycamore, and maple are among the other trees on its label.

What temperature is too cold for spraying?

Below 65 degrees Fahrenheit. The label sets a range of 65 to 95 degrees at the time of application.