How to Grow Summer Skies
Wikimedia Commons
Summer Skies
Delphinium elatum hybrid
flowerSummer Skies is a stunning hybrid delphinium cultivar prized for its tall spikes of semi-double blue flowers that resemble the color of a clear summer sky. These perennial flowers are dramatic garden specimens that can reach 4-6 feet tall and bloom prolifically in early to mid-summer. They are beloved by gardeners for their vibrant color and are excellent for cut flowers and traditional cottage gardens.
When should you plant Summer Skies in your zone?
Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.
Example Summer Skies timeline · Pittsburgh, PA (Zone 6b)
-
Plant Summer Skies
Around Apr 17Near Pittsburgh's average last spring frost.
-
Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
-
First Summer Skies blooms
Mid-to-late summerBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Summer Skies dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 3-7; prefers cooler climates and struggles in hot summers
Sign up free to see if Summer Skies grows in your zone — and get a personalized planting timeline.
Get my Summer Skies timeline →Growth Stages
Seedling
3-4 weeksTiny cotyledons emerge; require light exposure. Develops first true leaves within 2-3 weeks.
Keep soil moist; do not cover seeds. Provide bright light. Thin seedlings to prevent damping off.
Vegetative Growth
4-6 months first year; early spring second year until floweringDevelops deep green palmate foliage and establishes robust root system. First year plants focus on leaf growth.
Water consistently; provide stake support if indoors. Harden off transplants before planting outside. Apply mulch to retain moisture.
Budding & Flowering
4-8 weeks (June-July typically)Tall spikes emerge with densely packed semi-double blue flower buds opening progressively from bottom to top of spike.
Install sturdy stakes or grow-through supports; flowers are heavy. Deadhead spent lower flowers to encourage upper blooms. Water deeply to support heavy flower load.
Post-Bloom & Repeat Flowering
6-10 weeksAfter main bloom, foliage may decline in hot weather. Cut back spent spikes; plant may produce secondary shorter spikes in late summer/fall.
Cut flower spikes to 12 inches; fertilize with balanced fertilizer. Provide afternoon shade and consistent water during heat. Deadhead to encourage repeat flowers.
Dormancy
3-4 months (November-March)Foliage dies back in fall/winter; plant becomes dormant underground. New shoots emerge the following spring.
Cut back dead foliage in fall. Apply winter mulch in cold zones (3-4 inches). Avoid overwatering dormant plants.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
-
Remove infested buds and shoot tips; insecticidal soap; thin plants for air circulation
-
and
Hand-pick; copper tape barriers; beer traps; neem oil; encourage predators
-
Increase humidity; spray with water; insecticidal soap; neem oil
-
Improve air circulation; avoid overhead watering; sulfur dust; neem oil; remove infected leaves
-
Strong water spray; insecticidal soap; neem oil; beneficial insects like ladybugs
Uses
Crystallized Flowers for Decoration
CulinaryIndividual delphinium flowers can be carefully crystallized with egg white and sugar to create decorative elements for cakes and desserts. These are primarily decorative and not consumed in significant quantity. [source]
Cut Flowers & Arrangements
CraftSummer Skies' tall blue spikes are prized for wedding bouquets, vertical floral arrangements, and cottage garden cut-flower displays. Their substantial height and color make them a dramatic focal point in any arrangement. [source]
Garden Specimen & Cottage Gardening
HouseholdUsed as a tall background plant or focal point in perennial borders, cottage gardens, and traditional English gardens. Creates impressive vertical interest and attracts pollinators. [source]
Pollinator Attraction
WildlifeAttracts honeybees, bumblebees, and other pollinators with abundant nectar and pollen. Supports early summer pollinator populations when they are most active. [source]
Traditional Herbal Use
MedicinalHistorically used in traditional herbalism; modern use is limited due to toxicity concerns. Contains alkaloids that have been studied for potential pharmaceutical applications, though the plant itself is not typically consumed. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Cut flower spikes in early morning when lowest flowers are fully open. Cut stems at base with sharp knife; remove lower leaves. Condition in cool water for 2+ hours before arranging. Recut stems every few days and change water frequently. Vase life: 7-14 days. For garden display, deadhead spent flowers to encourage reblooming.
Fun Facts
- 🌱 Delphinium seeds can remain viable in soil for over 5 years, occasionally producing unexpected volunteer plants years after the parent plant has died.
- 🌱 The name 'delphinium' comes from the Greek word for dolphin (delphin) because the flower's nectar spur was thought to resemble a dolphin's nose.
- 🌱 Summer Skies produces some of the truest blue flowers in the garden—a color that is relatively rare in nature and has made delphiniums historically valuable for dye production.
Gardening Terms
New to gardening? Learn about terms used in this guide:
Join 30,000 gardeners planning their gardens with LizPlants.
Get your personalized Summer Skies planting timeline
Tell us your zip code and we'll calculate exactly when to start Summer Skies seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.
Get my Summer Skies timeline →