Delphinium vs Penstemon

Side-by-side plant comparison — which is right for your garden?

Delphinium

Delphinium elatum

Ranunculaceae · flowers

Deer ResistantHigh Maintenance

Penstemon

Penstemon digitalis

Plantaginaceae · flowers

Deer ResistantDrought TolerantLow Maintenance

Hardiness Zone Range

Delphinium (Zones 3-7)

Penstemon (Zones 3-8)

Overlap: Both grow in zones 3–7

Detailed Comparison

Feature	Delphinium	Penstemon
Scientific Name	Delphinium elatum	Penstemon digitalis
Family	Ranunculaceae	Plantaginaceae
Category	flowers	flowers
Sun	☀️ Full Sun	☀️ Full Sun
Water	💧💧 Medium	💧 Low
Soil	Rich, Well-drained	Well-drained
Height	6'	3'
Spread	2'	1' 6"
Bloom Season	Early Summer	Early Summer
Bloom Color	Blue, Purple, White, Pink	White, Pink, Purple
Growth Rate	Fast	Medium
Native Region	Europe, Asia	North America
Maintenance	High	Low

Special Traits

Delphinium

No — EdibleYes — Deer ResistantNo — Drought Tolerant

Penstemon

No — EdibleYes — Deer ResistantYes — Drought Tolerant

Care Tips

Delphinium

✓Stake tall varieties.
✓Cut back after first bloom for possible rebloom.
✓Needs cool summers — struggles in heat.
✓Slugs love young growth.
✓All parts are toxic.

Penstemon

✓Excellent drainage essential — root rot is the main killer.
✓Don't over-fertilize or overwater.
✓Cut back after first flush for possible rebloom.
✓Short-lived but self-seeds.

Which Plant Is Right for Your Garden?

Choose Delphinium if you don't mind high maintenance, and want deer resistance. It thrives in full sun with medium water in zones 3–7.

Choose Penstemon if you want a low-maintenance plant, need drought tolerance, and want deer resistance. It thrives in full sun with low water in zones 3–8.

Plant them together? Both overlap in zones 3–7. They share similar sun requirements (full sun), making them potential garden companions.

View DelphiniumProfile →View PenstemonProfile →

Frequently Asked Questions

Can Delphinium and Penstemon grow in the same hardiness zone?

Delphinium grows in USDA zones 3-7, while Penstemon grows in zones 3-8. Both plants can grow together in zones 3 through 7.

Do Delphinium and Penstemon have the same sun and water needs?

Delphinium needs full sun and medium water, while Penstemon needs full sun and low water. Their differing requirements mean you may need separate garden areas for each.

Which grows taller, Delphinium or Penstemon?

Delphinium grows taller at 6' compared to Penstemon at 3'. Delphinium spreads 2' while Penstemon spreads 1' 6".

Are Delphinium and Penstemon deer resistant?

Yes, both Delphinium and Penstemon are considered deer resistant, making them excellent choices for gardens in areas with deer pressure.

Which is easier to maintain, Delphinium or Penstemon?

Delphinium has high maintenance while Penstemon has low maintenance. Penstemon may be easier for beginning gardeners to manage.

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Detailed Comparison

Feature	Delphinium	Penstemon
Scientific Name	Delphinium elatum	Penstemon digitalis
Family	Ranunculaceae	Plantaginaceae
Category	flowers	flowers
Sun	☀️ Full Sun	☀️ Full Sun
Water	💧💧 Medium	💧 Low
Soil	Rich, Well-drained	Well-drained
Height	6'	3'
Spread	2'	1' 6"
Bloom Season	Early Summer	Early Summer
Bloom Color	Blue, Purple, White, Pink	White, Pink, Purple
Growth Rate	Fast	Medium
Native Region	Europe, Asia	North America
Maintenance	High	Low

Care Tips

Delphinium

✓Stake tall varieties.
✓Cut back after first bloom for possible rebloom.
✓Needs cool summers — struggles in heat.
✓Slugs love young growth.
✓All parts are toxic.

Penstemon

✓Excellent drainage essential — root rot is the main killer.
✓Don't over-fertilize or overwater.
✓Cut back after first flush for possible rebloom.
✓Short-lived but self-seeds.

Which Plant Is Right for Your Garden?

Choose Delphinium if you don't mind high maintenance, and want deer resistance. It thrives in full sun with medium water in zones 3–7.

Choose Penstemon if you want a low-maintenance plant, need drought tolerance, and want deer resistance. It thrives in full sun with low water in zones 3–8.

Plant them together? Both overlap in zones 3–7. They share similar sun requirements (full sun), making them potential garden companions.

Frequently Asked Questions

Can Delphinium and Penstemon grow in the same hardiness zone?

Delphinium grows in USDA zones 3-7, while Penstemon grows in zones 3-8. Both plants can grow together in zones 3 through 7.

Do Delphinium and Penstemon have the same sun and water needs?

Delphinium needs full sun and medium water, while Penstemon needs full sun and low water. Their differing requirements mean you may need separate garden areas for each.

Which grows taller, Delphinium or Penstemon?

Delphinium grows taller at 6' compared to Penstemon at 3'. Delphinium spreads 2' while Penstemon spreads 1' 6".

Are Delphinium and Penstemon deer resistant?

Yes, both Delphinium and Penstemon are considered deer resistant, making them excellent choices for gardens in areas with deer pressure.

Which is easier to maintain, Delphinium or Penstemon?

Delphinium has high maintenance while Penstemon has low maintenance. Penstemon may be easier for beginning gardeners to manage.