Hydrangea macrophylla 'Bailmer' ENDLESS SUMMER

Tried and Trouble-free Recommended by 10 Professionals
Common Name: bigleaf hydrangea
Type: Deciduous shrub
Family: Hydrangeaceae
Zone: 4 to 9
Height: 3.00 to 4.00 feet
Spread: 3.00 to 4.00 feet
Bloom Time: July to September
Bloom Description: Pink edged with white
Sun: Part shade
Water: Medium
Maintenance: Low
Suggested Use: Hedge
Flower: Showy


Unlike other H. macrophylla cultivars, ENDLESS SUMMER (1) blooms on both old and new growth and (2) is winter hardy to U.S.D.A. Zone 4, all of which means that plants will, within their growing range, reliably flower each year, regardless of winter temperature, and do not need to be covered with burlap in winter. Best grown in rich, medium moisture, well-drained soils in part shade. Tolerates full sun only if grown with consistently moist soils. Soil pH affects the flower color (blue in highly acidic soils and lilac to pink in slightly acidic to alkaline soils). Add aluminum sulfate to the soil to make the flowers bluer or add lime to the soil to make the flowers pinker. Begin soil treatments well in advance of flowering, as in late autumn or early spring. Prune after flowering by cutting back flowering stems to a pair of healthy buds. Prune out weak or winter-damaged stems in early spring.

Noteworthy Characteristics

Big leaf hydrangea is a deciduous shrub with a rounded habit that, in the St. Louis area, typically grows 3-6’ tall and as wide unless damaged by harsh winters or pruned smaller. It generally features dark green, serrate, obovate to elliptic leaves (4-8” long) and large clusters of long-blooming summer flowers. Flowers appear in two types or groups: (1) LACECAP GROUP which features flattened flower clusters (corymbs) of small fertile florets with scattered showy sterile florets often forming a marginal ring, and (2) MOPHEAD or HORTENSIA GROUP which features rounded, globose, mophead-like clusters (corymbs) of mostly showy sterile florets. ENDLESS SUMMER is a mophead-like cultivar that is significantly different from other mop heads currently in commerce today because of its unique ability to bloom on both old and new growth and its extremely good winter hardiness. ENDLESS SUMMER plants produce flower buds not only in fall but also on new growth in spring and summer. It may be grown in acidic soils for its blue florets or in alkaline soils for pinker florets. Dark green, serrate, obovate to elliptic leaves (4-8” long). Repeat blooms from July to fall.


No serious insect or disease problems. Some susceptibility to bud blight, bacterial wilt, leaf spot and mildew. Aphids are occasional visitors.

Garden Uses

Group or mass in a sheltered location in the shrub border. Also a good specimen or accent for foundations and other locations near homes or patios. Hedge.