Hydrangea Endless Summer
Hydrangea macrophylla 'Endless Summer'
A revolutionary reblooming hydrangea that produces stunning blooms on both old and new wood, extending the flowering season from spring through fall. The large, rounded flower heads change color based on soil pH, creating a dynamic display that evolves throughout the growing season. This hardy variety has transformed hydrangea growing by offering continuous blooms and exceptional cold tolerance.
Harvest
N/Ad
Days to harvest
Sun
Partial shade to morning sun
Zones
6–11
USDA hardiness
Height
3-6 feet
Planting Timeline
Showing dates for Hydrangea Endless Summer in USDA Zone 7
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Hydrangea Endless Summer · Zones 6–11
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | April – May | June – July | June – August | — |
| Zone 4 | March – April | June – June | June – July | — |
| Zone 5 | March – April | May – June | May – July | — |
| Zone 6 | March – April | May – June | May – July | — |
| Zone 7 | February – March | April – May | April – June | — |
| Zone 8 | February – March | April – May | April – June | — |
| Zone 9 | January – February | March – April | March – May | — |
| Zone 10 | January – January | February – March | February – April | — |
Complete Growing Guide
Soil: Clay, High Organic Matter, Loam (Silt), Sand. Soil pH: Acid (<6.0), Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Occasionally Wet. Height: 3 ft. 0 in. - 6 ft. 0 in.. Spread: 3 ft. 0 in. - 6 ft. 0 in.. Spacing: 3 feet-6 feet. Growth rate: Rapid. Maintenance: Low. Propagation: Layering, Leaf Cutting, Stem Cutting. Regions: Coastal, Mountains, Piedmont.
Harvesting
cup-like capsule
Type: Capsule.
Harvest time: Fall
Bloom time: Summer
Storage & Preservation
Fresh hydrangea stems last 5-7 days in arrangements when properly conditioned. Immediately after cutting, place stems in lukewarm water and recut under running water. Strip leaves below the waterline and crush or split woody stem ends to improve water uptake. Keep arrangements away from direct sunlight and change water every 2-3 days.
For air drying, strip leaves and hang bundles upside down in a dark, well-ventilated area for 2-3 weeks. Alternatively, place stems in containers with 2 inches of water and let them slowly dry as water evaporates—this method often produces better color retention.
Glycerin preservation maintains flexibility and creates elegant displays. Mix one part glycerin with two parts warm water, and place freshly cut stems in the solution for 3-6 days until petals feel supple. Properly preserved hydrangeas maintain their beauty for months in dried arrangements and wreaths.
History & Origin
Endless Summer hydrangeas were developed by Bailey Nurseries in Minnesota through their collaboration with plant breeder Michael Dirr in the 1980s. The original plant was discovered in a Minnesota garden where it had survived harsh winters while continuing to bloom—unusual for macrophylla hydrangeas that typically only flowered on old wood in northern climates.
The breakthrough came from recognizing that this particular hydrangea bloomed on both old wood (previous year's growth) and new wood (current season's growth). This trait, called remontancy, meant gardeners in colder zones could enjoy blooms even if winter killed the previous year's stems.
Bailey Nurseries introduced the first Endless Summer variety, 'Bailmer,' to the market in 2004 after years of testing and propagation. The name reflects its extended blooming season—from spring through fall in optimal conditions. This revolutionary characteristic transformed hydrangea growing in northern climates and sparked development of additional reblooming hydrangea series. The success of Endless Summer proved that innovative plant breeding could solve long-standing gardening challenges, making beloved plants accessible to gardeners in previously unsuitable climates.
Advantages
- +Disease resistance: Salt
- +Attracts: Height: 3 ft. 0 in. - 6 ft. 0 in., Width: 3 ft. 0 in. - 6 ft. 0 in.
- +Wildlife value: Dead stems are used by stem-nesting bees.
- +Fast-growing
- +Low maintenance
Considerations
- -Toxic (Bark, Flowers, Leaves): Low severity
Companion Plants
Plant Together
Hosta
Thrives in similar partial shade conditions and provides contrasting foliage texture
Astilbe
Shares preference for moist, well-draining soil and partial shade
Fern
Creates natural woodland understory effect and enjoys same acidic soil conditions
Heuchera
Complements with colorful foliage and tolerates similar light and moisture conditions
Camellia
Both prefer acidic soil and partial shade, blooms at different times extending garden interest
Azalea
Shares acidic soil requirements and creates beautiful spring-summer bloom succession
Japanese Painted Fern
Provides striking silver foliage contrast and thrives in same moist, shaded conditions
Impatiens
Fills understory space with continuous color and enjoys same partial shade environment
Keep Apart
Black Walnut Tree
Produces juglone toxin that can stunt hydrangea growth and cause leaf yellowing
Eucalyptus
Releases allelopathic compounds that inhibit growth of nearby plants
Pine Trees
Creates too much shade and acidic needle drop can make soil overly acidic
Nutrition Facts
Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #169270)
Pests & Disease Resistance
Resistance
Good resistance to powdery mildew and leaf spot
Common Pests
Aphids, spider mites, scale insects
Diseases
Powdery mildew, leaf spot, root rot in poorly drained soil