Penstemon ‘King George’ – Growing Guide
Penstemon ‘King George’ is a standout border plant, prized for its bold tubular flowers, long flowering season, and excellent resilience in UK gardens. With its upright habit and vivid blooms, it’s a great pollinator plant and an easy-care choice for both new and experienced gardeners. This guide covers everything you need to grow it successfully.
1. Planting Location
Sunlight
Choose a bright, sunny spot with 6–8 hours of sunlight daily.
More sun = strong stems and more flowers.
Soil
- Prefers well-drained, sandy or loamy soil
- Avoid heavy clay or persistently wet ground
- Improve drainage with grit or compost if needed
2. Best Time to Plant
- Spring after the last frost
- Autumn in mild areas, allowing roots time to establish
3. Spacing & Layout
Give each plant 18–24 inches of space for airflow and healthy growth.
Great for:
- Mixed borders
- Cottage gardens
- Pollinator beds
- Mass planting for impact
4. Watering
After Planting
Water regularly to help roots establish.
Once Established
Penstemons are drought-tolerant. Allow the soil to dry between waterings.
Avoid overwatering — they prefer leaner conditions.
5. Fertilising
Type
Use a balanced, slow-release fertiliser.
When
- Once in early spring
- Optional light boost during peak flowering
Avoid high-nitrogen feeds, which cause floppy growth.
6. Pruning & Deadheading
Deadhead Often
Removing faded blooms encourages continuous flowering.
Seasonal Pruning
- Do NOT prune hard in autumn
- Keep some top growth for frost protection
- Cut back fully in early spring to stimulate fresh shoots
7. Pest & Disease Care
Generally Low-Maintenance, but watch for:
- Aphids
- Slugs/snails attacking new shoots
How to Prevent Problems
- Ensure good airflow
- Avoid overhead evening watering
- Use grit mulch to deter slugs
8. Winter Care
Hardiness
Generally hardy in zones 4–8.
Cold-Climate Tips
- Mulch around the base in late autumn
- Leave old stems over winter for root protection
- Cut back in spring when new growth appears
Why Grow Penstemon ‘King George’?
- Long flowering season (summer to autumn)
- Loved by bees and pollinators
- Ideal for UK borders
- Low maintenance & drought tolerant
- A proven bestseller at Dartana, as seen in repeat sales of Penstemon King George Perennial x 5 Pack and Penstemon King George Perennial x 3 Pack plug plants [You made t...EE Postage | Outlook], [Penstemon...een listed | Outlook]
FAQs
Is Penstemon ‘King George’ hardy?
Yes — hardy in most UK gardens with minimal winter care.
Will it flower in partial shade?
It can, but flowering is heaviest in full sun.
Do I cut it back in autumn?
No — leave stems over winter and prune in early spring.
Is it good for pollinators?
Very — bees love the tubular blooms.
Does it grow well in clay?
Only with improved drainage. Add grit and organic matter.
