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Growing Penstemons: A Comprehensive Guide for Beginners

by Donna
4 minutes read

Growing Penstemons: A Comprehensive Guide


Penstemons are beautiful and versatile plants that are easy to grow and provide long-lasting color to your garden. With their tubular-shaped flowers and variety of colors, penstemons are a great choice for attracting pollinators and adding interest to your borders.

Types of Penstemons

There are many different types of penstemons, each with its own unique characteristics. Some penstemons are well-suited to alpine gardens, while others are more at home in the heart of a herbaceous border. Border penstemons have tubular late summer flowers in a wide range of colors, from crimson to purple to yellow.

How to Grow Penstemons

Penstemons are relatively easy to grow, but they do have a few specific requirements. They prefer moist but well-drained soil in full sun to partial shade. Mulch annually with well-rotted manure or leaf mold, and feed weekly in summer. Penstemons are short-lived perennials that can suffer in winter, so it’s important to take steps to protect them from the cold.

Planting Penstemons

The best time to plant penstemons is in spring, so that new plants have a chance to get established before winter. Choose a planting site that receives full sun or partial shade and has well-drained soil. Dig a hole that is twice the width of the root ball and just as deep. Place the penstemon in the hole and backfill with soil, tamping down gently to remove any air pockets. Water deeply after planting.

Propagating Penstemons

Penstemons can be propagated by seed, cuttings, or division.

  • Seed: Penstemon seeds can be sown indoors in late winter or early spring. Sow the seeds on the surface of a moist seed starting mix and cover lightly with vermiculite. Keep the seeds warm and moist, and they should germinate in 10-14 days.
  • Cuttings: Penstemon cuttings can be taken from soft growth in late summer or early autumn. Cut each cutting back to below a leaf joint and remove the lower leaves. Dip the end of the cutting in rooting hormone and then plant it in a pot of moist potting mix. Keep the cuttings warm and moist, and they should root in 4-6 weeks.
  • Division: Penstemons can also be propagated by division in spring or fall. Dig up the plant and carefully divide it into smaller sections. Each section should have at least one growing point and some roots. Replant the divisions in well-drained soil and water deeply.

Caring for Penstemons

Penstemons are relatively low-maintenance plants, but they do require some basic care to keep them healthy and blooming.

  • Watering: Penstemons need regular watering, especially during hot and dry weather. Water deeply at the base of the plant, avoiding the leaves.
  • Fertilizing: Feed penstemons monthly with a balanced fertilizer.
  • Deadheading: Deadheading spent flowers will encourage new blooms. Simply remove the flower spikes as they fade.
  • Pruning: Penstemons should be pruned back hard in spring to remove any dead or damaged growth.

Troubleshooting Penstemon Problems

Penstemons are generally trouble-free plants, but they can sometimes be affected by pests or diseases.

  • Aphids: Aphids are small, soft-bodied insects that can suck the sap from penstemon leaves. Treat aphids with insecticidal soap or neem oil.
  • Powdery mildew: Powdery mildew is a fungal disease that can cause white powdery spots on penstemon leaves. Treat powdery mildew with a fungicide.
  • Root rot: Root rot is a fungal disease that can cause the roots of penstemons to rot. Root rot can be prevented by planting penstemons in well-drained soil and avoiding overwatering.


Penstemons are beautiful and easy-to-grow plants that are a great addition to any garden. With their long-lasting blooms and variety of colors, penstemons are sure to add beauty and interest to your garden for years to come.

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