Penstemon Plant Care

Growing penstemon will attract hummingbirds and butterflies to your garden.

Penstemon is native to the western U.S. and often thought of as a wildflower, though there are hundreds of penstemon hybrids to choose from for your garden. The wide variety of penstemon allows you to select flower color, size and hardiness. Most penstemon are considered hardy perennials, but there are some that are less hardy and, therefore, considered an annual. No matter which variety you decide to grow, the care of the plant is the same for all varieties.

Site Selection

Penstemon is generally easy to grow and low maintenance. The ideal growing location is in full sun, with good-draining soil. Growing your penstemon plants in raised beds or sloping landscape will help prevent the soil from becoming waterlogged, something penstemon plants do not grow well in. Penstemon is a drought-tolerant plant.

Soil Preparation

Because penstemon prefer well-draining soil and drier soil conditions, it is important to amend the soil where you grow your penstemon if it is anything other than a sand-based soil. A good formula to use when amending soil is to add one part sand or pea gravel to two parts soil. Thoroughly mix this together with a till or shovel where the penstemon plants will grow. The addition of sand or pea gravel will allow better water drainage and air to the roots.

General Care

Besides not overwatering your penstemon plants, weed control and avoiding overcrowding are key to keeping your plants happy. Mulch with 2 to 3 inches of bark or organic matter around the plants for weed control and to retain moisture in the soil. Water during the summer during spells where less than 1 inch of rain is received. Penstemons are light feeders and do not require regular fertilizing, though monthly applications of a liquid all-purpose fertilizer will not harm the plant.

The showy flowering spikes can be cut for floral arrangements, or left on the plant to attract hummingbirds and butterflies, but should be pruned off once the flowers are spent to promote continuous blooming. At the end of the growing season, cut the foliage back to 3 to 4 inches, mulching over the plant in colder regions.

Problems

Penstemon plants are not troubled by most insects, except for an occasional slug or snail eating on new growth. Powdery mildew, rust and leaf spots can be a problem for your penstemon plants. Leaf spots usually occur during periods of wet weather and can be controlled with an appropriate fungicide for the condition as soon as leaf spot is noticed. Powdery mildew can appear at any time, but is more common when humidity levels are high. As soon as powdery mildew is observed on your penstemon leaves, apply a fungicide that can control the disease. Fungicide also will control infections of rust, first found on the underside of foliage as powdery looking rust spots. The sooner you apply the fungicide to your penstemon plants when any of the aforementioned ailments are noticed, the better chance you have of eliminating the disease.

References

• National Gardening Association: Penstemon
• State of Connecticut: Penstemon
• Ohio State University: Penstemon