Creeping bellflower Campanula rapunculoides
IDENTIFICATION — Most bellflowers are well-behaved garden plants, but creeping bellflower, or rampion, is just a little too aggressive. This perennial has toothed leaves, almost heart-shaped at the base and narrower toward the top. The plant can reach 1 to 3 ft. high, and oozes a milky sap when it’s broken. The bell-shaped flowers bloom from the bottom of the stem to the top, in July through September. This weed spreads by its vigorous underground root system, and it can also reseed.
FAVORITE CONDITIONS — Creeping bellflower is found throughout most of the United States and Canada, except for the far southeastern states, Arizona and southern California. It grows almost anywhere. Although it grows in either sun or shade, it’s most aggressive in moist, shady conditions.
CONTROL — Getting rid of creeping bellflower can take several years, so don’t be discouraged if it keeps reappearing. Mowing the plants early will keep them from reseeding. You can dig out the fleshy roots, but you’ll need to dig at least 6 in. down and several inches out from the plant to get them all. Even small pieces can form new plants.
Herbicides containing glyphosate (Roundup®) are effective against creeping bellflower. Apply it in late spring or early fall for the best effect, and be careful not to get any on your other garden plants.