Common Name: bigleaf hydrangea
Type: Deciduous shrub
Family: Hydrangeaceae
Zone: 5 to 9
Height: 2.00 to 3.00 feet
Spread: 2.00 to 3.00 feet
Bloom Time: June to August
Bloom Description: Pink (neutral to alkaline soils) to purple (acidic soils)
Sun: Part shade
Water: Medium
Maintenance: Medium
Flower: Showy, Good Cut, Good Dried
Culture
Best grown in rich, medium moisture, well-drained soils in part shade. Tolerates full sun only if grown in consistently moist soils. Soil pH affects the flower color of most cultivars except white (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. Plants generally need little pruning. If needed, prune immediately after flowering by cutting back flowering stems to a pair of healthy buds. Prune out weak or winter-damaged stems in late winter/early spring. Best to mulch plants year-round with 3" of shredded bark, peat or compost. Winter hardy to USDA Zone 6. For added protection, however, plants grown in USDA Zone 5 should be sited in sheltered locations and given additional winter protection, as needed, for the purposes of minimizing the risk of loss of significant numbers of flower buds or possible die-back to the ground in an extremely harsh winter. A burlap wrap of stems or circle of chicken wire filled with leaves or straw to 8-12" are time-consuming and visually unattractive landscape options, but can be effective. Regardless of protective measures taken, most bigleaf hydrangeas simply will not bloom (or will bloom poorly) in some years because of a variety of winter occurrences beyond the control of the gardener (e.g. low temperatures, sudden wide temperature fluctuations, icy conditions, late frosts). Some newer cultivars have been selected that flower on both old and new wood. Their pruning and flowering can differ from that of the species.
Noteworthy Characteristics
Hydrangea macrophylla, commonly called 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 serrate, obovate to elliptic, dark green leaves (4-8” long) and large clusters of long-blooming summer flowers in either lacecap form (flattened flower clusters of small fertile florets with scattered showy sterile florets often forming a marginal ring) or mophead form (globose flower clusters of mostly showy sterile florets).
The genus name Hydrangea comes from hydor meaning "water" and aggeion meaning "vessel", in reference to the cup-like capsular fruit.
Specific epithet comes from the Greek words makros meaning large and phyllon meaning leaf in reference to plant leaves.
'SMNHMP' is a reblooming, hybrid hydrangea selection featuring large, mophead-type flowerheads and a compact growth habit. This cultivar resulted from a cross between Hydrangea macrophylla 'Cityline Lisbon' and H. macrophylla 'Wyatt LeFever'. The dense, rounded, 6.5" wide flowerheads bloom on both old and new wood, with the first flush of blooms in early summer followed by sporadic reblooming through the rest of the summer. The flowerheads are made up of sterile florets that will take on shades of pink or deep purple depending on the soil pH. Mature plants will reach up to 3' tall with a similar spread. Commonly sold at nurseries and garden centers under the name LET'S DANCE BIG BAND. This plant is protected by patent number PP32514.
Problems
Some susceptibility to bud blight, bacterial wilt, leaf spot and mildew. Aphids are occasional visitors.
Uses
Group or mass in the shrub border. Also a good specimen or accent for foundations and other locations near homes or patios. Hedge. Containers.
Group or mass in the shrub border. Also a good specimen or accent for foundations and other locations near homes or patios. Flowers can be used in fresh-cut or dried arrangements. Suitable for use in large containers