Foxglove (Digitalis) Care: Growing Tall, Toxic Spires

Foxgloves (Digitalis) bring dramatic vertical accents and old-world charm to the garden with their towering spires of tubular, bell-shaped flowers, often speckled inside. Blooming in late spring to mid-summer, typically in shades of purple, pink, rose, white, yellow, and apricot, they are favorites in cottage gardens and woodland settings. Most common garden foxgloves (D. purpurea) are biennials, growing a rosette of leaves the first year and flowering the second, though perennial species also exist. Extreme caution is required as all parts of the plant are highly toxic.

Common Types of Foxglove

Understanding the life cycle is key:

• Common Foxglove (Digitalis purpurea):

  • The classic, most widely grown type. Strictly biennial.
  • Forms a low rosette of fuzzy leaves in year one. Sends up a tall (3-6 ft) spike of large, pendant, bell-shaped flowers (usually purple or white, often speckled) in year two, sets seed, and dies.
  • Readily self-sows if stalks are left standing. Seedlings may vary in color.
  • Numerous cultivars exist, including the 'Excelsior' strain (flowers all around stem) and 'Foxy' (can sometimes bloom first year from early sowing). Zones 4-8.

• Perennial Foxgloves:

  • Live for more than two years, though often still relatively short-lived perennials (3-5 years). Tend to have smaller flowers than D. purpurea.
  • Examples:
    • D. lutea (Straw Foxglove): Slender spikes of small, pale yellow flowers. Reliable perennial. Zones 3-8.
    • D. grandiflora (syn. D. ambigua) (Yellow Foxglove): Larger pale yellow flowers than D. lutea. Zones 3-8.
    • D. mertonensis (Strawberry Foxglove): Hybrid with crushed-strawberry pink flowers. Short-lived perennial. Zones 3-8.
    • D. x fulva ('Spice Island'): Hybrid with coppery-apricot tones. Often perennial. Zones 5-9.

Planting Foxglove

Best started from seed or young plants.

Starting from Seed

• Timing:
  • For Biennial Cycle: Sow seeds outdoors mid-summer directly where they are to grow or in nursery beds for transplanting in fall. This allows rosettes to establish before winter for blooms next spring/summer.
  • For Annual Bloom (e.g., 'Foxy'): Start seeds indoors 6-10 weeks before last frost.
  • Perennial Types: Can be sown spring or summer.
• Sowing: Seeds are tiny and need light to germinate. Sow on the soil surface and press in gently. Do not cover with soil. Keep consistently moist. Germination takes 2-3 weeks. Thin seedlings to 1-1.5 feet apart.

Planting Container-Grown Plants

• Timing: Plant basal rosettes (first-year plants) or perennial types in spring or fall.
• Handling: Handle gently, especially the foliage rosette.

Ideal Growing Conditions

• Light: Partial shade (especially afternoon shade) is ideal in most climates. Tolerates full sun if the soil remains consistently moist, particularly in cooler regions. Deep shade reduces flowering.
• Soil: Requires rich, moist, humusy, and well-draining soil. They dislike both drought and waterlogged conditions. Slightly acidic soil is preferred.
• Spacing: Space plants 1-1.5 feet apart. Good air circulation helps prevent fungal diseases.

Planting Technique

Watering Foxglove

• Foxgloves prefer consistently moist soil, especially during their flowering period. Do not allow the soil to dry out completely.
• Water deeply when the top inch of soil feels dry. Mulching helps conserve moisture.
• Ensure good drainage to prevent crown rot, especially in winter.

Fertilizing Foxglove

• Foxgloves appreciate fertile soil but are not heavy feeders.
• Incorporating plenty of compost at planting time is usually sufficient.
• If desired, apply a light dose of balanced, slow-release fertilizer in early spring when growth resumes. Avoid excessive nitrogen.

Maintenance and Care

Deadheading / Stalk Removal

• After flowering, cut the main flower stalk down to the basal rosette. This prevents seed formation and can sometimes encourage smaller side stalks to bloom (especially on D. purpurea).
• Removing the stalk before seeds mature also prevents potentially prolific self-seeding if that is not desired.
• Alternatively, leave stalks standing to allow seeds to mature and self-sow for future plants (essential for maintaining biennial types).

Handling Biennials

• Remember that the main rosette of D. purpurea will die after flowering in its second year. Remove the dead plant. Allow seedlings to develop nearby to continue the cycle.

Cleanup

• Remove dead foliage rosettes in late fall or early spring. Clean up any diseased foliage promptly.

Troubleshooting Common Problems

Ensure good drainage and air circulation.

Powdery Mildew / Leaf Spot / Anthracnose

Symptoms and Management

Fungal diseases causing white coating or spots on leaves, especially in humid weather or crowded conditions.

• Prevention/Control: Provide good air circulation (spacing). Avoid overhead watering. Remove infected leaves promptly. Ensure good drainage and avoid plant stress. Fungicides rarely needed for home gardens.

Crown Rot

Symptoms and Management

Rosette base rots, plant wilts and collapses.

• Cause: Poor drainage, overly wet soil, especially in winter. Planting crown too deep.
• Prevention: Ensure excellent drainage. Amend heavy soils. Plant crown at soil level. Avoid overwatering.

Aphids

Symptoms and Management

• Can cluster on flower stalks or new growth.
• Control: Wash off with water spray or use insecticidal soap if severe.

Conclusion

Foxgloves provide unparalleled vertical elegance and cottage garden charm with their towering spires of speckled bells. Understanding their often biennial life cycle and providing moist, well-drained soil in partial shade are key to success. While their beauty is undeniable, always exercise extreme caution due to their high toxicity. Grow them responsibly, keeping them away from children and pets, and enjoy their dramatic but fleeting presence in the early summer garden, often perpetuated through welcome self-seeding.