How to Grow Summer Bulbs
Summer Bulbs
Various genera (Gladiolus, Dahlia, Canna, Begonia, Lilium, Crocosmia, etc.)
flowerSummer bulbs are tender bulbous plants that bloom during warm months and must be planted after the last frost. They include a diverse group of ornamental flowers ranging from tall gladiolus spikes to colorful dahlias and dramatic cannas. Most are lifted and stored indoors over winter in cold climates, making them excellent for adding height, color, and structure to summer gardens.
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Example Summer Bulbs timeline · Pittsburgh, PA (Zone 6b)
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Plant Summer Bulbs
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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First Summer Bulbs blooms
Around Jun 16≈ 60 days after planting
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Growing Conditions
Soil
Growing Zones
Find your zone →Most summer bulbs thrive in zones 3-11; tender varieties need winter storage in zones below 8
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Dormant Bulb Storage
4-6 months (October-April in northern climates)Bulbs are stored dry in cool, dark conditions over winter. Look dry and hard with no signs of sprouting.
Store at 50-60°F in a dry location. Check monthly for rot or sprouting. Keep away from mice and insects. Dust with fungicide if needed.
Sprouting & Root Development
2-4 weeksRoots emerge from the bulb base and shoots push through soil. Visible growth above ground emerges within 1-3 weeks of planting.
Plant after last spring frost. Keep soil consistently moist. Provide mulch to retain moisture and regulate temperature. No fertilizer yet.
Vegetative Growth
3-6 weeksFoliage expands rapidly. Leaves are full and green, stems elongate, but no flower buds visible yet.
Water deeply 1-2 inches weekly. Apply balanced fertilizer (10-10-10) every 3-4 weeks. Tall varieties may need staking. Remove any damaged leaves.
Bud Formation & Blooming
3-8 weeks depending on varietyFlower buds develop at stem tips. Blooms open progressively from bottom to top (in gladiolus) or all at once (in dahlias). Colors deepen.
Switch to higher phosphorus/potassium fertilizer (5-10-10). Water at soil level to keep blooms dry. Deadhead spent flowers. Provide support if needed.
Harvest & Post-Bloom Rest
2-4 weeksFlowers fade. Foliage yellows and dies back naturally. Bulbs absorb nutrients from dying foliage to store energy.
Cut flowers for arrangements when first bloom opens. After bloom, reduce watering and stop fertilizing. Let foliage die completely before lifting. Lift bulbs after first frost; cure and store.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with insecticidal soap or neem oil. Remove infected flowers immediately. Use yellow sticky traps.
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Increase humidity by misting. Spray with miticide or neem oil. Remove heavily infested foliage.
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Hand-pick early morning. Use beetle traps away from plants. Apply neem oil or pyrethrin spray.
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Spray with strong water stream. Apply insecticidal soap or neem oil. Encourage beneficial insects like ladybugs.
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and
Handpick at night. Create barriers with copper tape or diatomaceous earth. Beer traps or pellets.
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Ensure excellent drainage. Avoid overwatering. Store bulbs in dry conditions. Dust with fungicide before storage.
Uses
Tuberous begonias in salads
CulinaryThe petals and tubers of some begonia varieties are edible and add delicate flavors and striking colors to salads and desserts. [source]
Long-lasting cut flowers
HouseholdSummer bulbs like gladiolus, dahlias, and lilies are prized for floral arrangements and cut flower displays, lasting 7-14 days in a vase. [source]
Garden color and structure
HouseholdSummer bulbs provide dramatic height, texture, and seasonal color to borders and beds. Tall varieties like dahlias reach 4-6 feet and create focal points. [source]
Pollinator attraction
WildlifeMany summer bulbs attract bees, butterflies, and hummingbirds. Gladiolus, cannas, lilies, and crocosmia are particularly valuable nectar sources. [source]
Traditional herbal uses
MedicinalSome summer bulbs, particularly ginger relatives and calla lilies, have traditional uses in herbal medicine, though modern evidence varies. [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 flowers when first bloom opens for longest vase life (10-14 days). Use clean, sharp shears. Cut in early morning or late evening. Bring indoors immediately and place in cool water. For bulb storage: Lift bulbs after first light frost (foliage yellowed). Cure in cool, dry location for 2-3 weeks. Remove soil gently, don't wash. Cut stems to 1-2 inches. Store at 50-60°F in breathable containers (not plastic bags). Check monthly and remove any rotting bulbs.
Fun Facts
- 🌱 Dahlias can produce blooms over 12 inches across and come in nearly every color except true blue; there are over 42,000 registered cultivars worldwide.
- 🌱 Gladiolus name comes from the Latin 'gladius' meaning sword, referring to the sword-shaped leaves and flowers that open sequentially from bottom to top.
- 🌱 Some summer bulbs like dahlias and cannas are perennial in warm zones (8+) but must be dug up and stored over winter in cold climates—a practice called 'tender bulbs.'
Gardening Terms
New to gardening? Learn about terms used in this guide:
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