Groundhogs are the home gardener's enemy. They enjoy munching on several types of green plants. Although sprinkling cayenne pepper near the base of plants is supposed to keep groundhogs from eating them, the process is tedious and time consuming as the cayenne pepper must be reapplied each time after it rains to be effective. Planting groundhog-resistant perennials is therefore the best defense at ensuring your plants will not become the neighborhood food source for groundhogs.
Groundhogs dislike blue star (amsonia, pointed blue-eye and eye-bright). The perennial has either white or blue-purple flowers with yellow centers. The flowers are flanked by pale green foliage located near the plant's base. It flowers between May and August. You sometimes find it growing wild in meadows and moist fields from about the Rocky Mountain's eastern slope to the Atlantic Ocean and extending south to Kansas and Virginia.
Groundhogs do not generally bother with daffodils. According to the American Daffodil Society, daffodil leaves have poisonous crystals that deter groundhogs and other rodents. This perennial blooms in the springtime with flowers appearing for about 6 weeks to 6 months based on your geographic region, states the American Daffodil Society. More than 40 different daffodil species exist, and most produce yellow or white colored flowers. Daffodils are relatively easy to grow and are a good option for novice gardeners.
Lavender is a highly fragrant perennial that starts blooming in early summer. It grows as a short shrub that contains several, heavy wooded branches that stand up to 24 inches tall. The spiked branches support thin green-gray foliage of a tapered oval shape. Lavender has tiny, blue-violet flowers at the end of its spikes, which produce its herb-like fragrance. Lavender is among the list of perennials considered wood-chuck-resistant (includes groundhogs) by the Internet Center for Wildlife Damage Management.
Gaura Siskyou Pink
The guara siskyou pink produces pretty, light pink blooms beginning in June and ending when the first frost occurs. During this bloom period, expect to find about eight or so flowers along a 15-inch stalk. The flower-producing plant has deep green foliage. Groundhogs and deer ignore this perennial, according to Denise Schreiber, contributing writer of the Pittsburgh Post-Gazette's April 21, 2002 edition of "The Backyard Gardener."