Penstemon, often called beardtongue, is a versatile perennial admired for its vibrant, tubular flowers that bloom over an extended season. Pruning is a foundational maintenance practice that involves strategic removal of plant material to direct the plant’s energy towards desired growth. This ensures its longevity and aesthetic appeal in the garden. Proper pruning techniques significantly enhance the performance and appearance of penstemons.
Why Prune Penstemon
Pruning penstemon offers several benefits for the plant’s overall health and flowering. Regular trimming promotes more blooms by encouraging new flower stalks instead of seeds. It also maintains the plant’s structural integrity, preventing it from becoming woody or leggy over time. Pruning enhances air circulation, discouraging fungal diseases. Removing dead, damaged, or diseased stems improves appearance and directs resources towards healthy growth, extending its lifespan.
When to Prune Penstemon
Timing is important when pruning penstemon, as different types are performed at specific times. Throughout the blooming season (late spring to early fall), deadhead spent flowers to encourage continuous rebloom by removing faded stalks as they wilt. For a more substantial cutback, late winter or early spring is generally the best time, just before new growth emerges. This annual cutback rejuvenates the plant, promoting a bushy habit and preventing it from becoming overly woody. In colder climates, leaving some old growth during fall and winter can provide protection for the crown.
How to Prune Penstemon
Effective penstemon pruning requires clean, sharp tools for precise cuts, preventing damage and disease. Bypass pruners are ideal for clean cuts on living stems. When deadheading, remove spent flower stalks by cutting them back to a healthy set of leaves or just above a lateral side shoot. This encourages the plant to produce new flowers instead of seeds.
For the annual late winter or early spring cutback, examine the plant for new shoots emerging from the base or along the stems. If new shoots are at the base, old stems can be cut back to about 1-2 centimeters (approximately 0.4-0.8 inches) from ground level. If new growth is primarily observed along the stems, prune just above the lowest healthy shoots or leaves, typically leaving about three to six inches of growth. This rejuvenation pruning encourages vigorous new growth and helps maintain a compact, attractive shape. Remove any dead, damaged, or diseased stems at their point of origin, making cuts at a 45-degree angle to prevent water pooling and rot.
Post-Pruning Care
After pruning, appropriate care helps penstemon plants recover quickly and supports robust new growth. Following a significant cutback, ensure the plant receives adequate moisture, especially if the weather is dry. While established penstemons are drought-tolerant, watering after pruning reduces stress and aids recovery.
For garden beds, a spring application of well-rotted manure or compost as mulch provides sufficient nutrients for new growth. Container-grown penstemons may benefit from a balanced general-purpose fertilizer in spring. Monitor the plant for signs of new growth and vigor. Observing its response allows for future care adjustments, ensuring continued health and blooms.