GOLDEN VALLEY, Minn. — We’re in the fourth and final week of our Grow with KARE — Fact or Fiction series, where we’ve been looking into common gardening advice and letting you know if it’s good advice or just a waste of time.
Let’s start today with preventing crabgrass. We hear the advice every spring to apply crabgrass preventer when the lilacs are blooming. No matter how popular the saying is, this one is fiction. If you wait to apply the preventer when the lilacs are in bloom, it’s likely too late. Instead, use a soil thermometer and apply when the soil is consistently 50 degrees, which is usually before lilac bloom and instead during or just after forsythias are in bloom.
Another common saying is that peonies need ants to open. Fiction. The peonies do not NEED the ants. Instead, the ants and peonies share a mutually beneficial relationship. The ants feed off the nectar that emerges from the peony buds and in return protect the flowers from other insects that may damage or eat the blooms.
And last up: Is it true nothing will grow under a black walnut tree? No, this is fiction. Black walnut trees do secrete a chemical called juglone from their roots which is toxic to a few plants, but most trees, shrubs and flowers tolerate juglone. Bee balm, phlox, begonias and crocus, as well as squash, melons, beans and corn will thrive. Avoid planting tomatoes, peppers and potatoes near a black walnut tree.