Hydrangea macrophylla, is one of the best hydrangeas species with many cultivars available. The big-leaf hydrangea (French hydrangea), is the most popular and widely known hydrangea. Find Pruning facts and information on growing and caring for Hydrangea macrophylla species, as well as a list of the best species available.
If you should take a drive along a seashore or along the East Coast, you will see a proliferation of fat, blue mopheads. These fast-growing, classic garden hydrangeas, suckering and unbranched, complement both traditional and contemporary landscapes, adding shades of pink and blue to beds, borders, and foundation plantings.
The big, dark green leaves are serrated. The tan stems occasionally peel or split. In the North, stems can die back in winter with new growth emerging from the roots.
Types of Hydrangea Flowers
Hortensias, or mopheads, are big heavy balls of showy, sterile flowers. Lacecaps are subtler in effect, being flat or domed discs of delicate fertile blooms ringed by showy, sterile flowers. Both types may have flower buds at the shoot tips and along the stems.
Their color depends upon the amount of available aluminum in the soil. Acidity in the soil frees up the aluminum, leading to blue to deep purple flowers. Alkaline soils bind the aluminum ions so that they’re not accessible to the roots, and here the flowers are shades of pink. The fruits are not ornamental. Excellent salt tolerance makes this a good choice for shady areas on the coast. Drying Hydrangea flowers is often done to produce flowers for dried flower arrangements.
You will find that short cultivars make terrific salt-tolerant foundation plantings for beach houses. Use massed under trees that give dappled shade. Choose from dozens of cultivars: Blue-flowered forms look stunning next to sunny yellow ir chartreuse-leafed shrubs, and cultivars with variegated leaves brighten woodland shrub beds and borders. These shrubs work well in the midst of perennial borders, where spring flowers mask hydrangea’s coarse leaves until their summer blooms begin.
Planting Hydrangea macrophylla
Origin of Hydrangea macrophylla plants go back to Korea and Japan. Zones 6-9 are ideal for growing macrophylla varieties. Plant in partial shade to full sun. Morning sun and afternoon shade is ideal. Hydrangeas will wilt in hot climates where the heat and afternoon sun is intense.
The soil’s pH and the resulting accessibility of aluminum ions determines the flower hue. For pink flowers, the soil pH should be from 6.0- 6.5 or above. Liming acid soils can raise the pH and produce pinker blooms. Using hard water and growing hydrangeas near concrete sidewalks and house foundations also increases the soil’s pH.
For blue blooms, the soil pH is usually acid (below 5.5). Sulfur, iron sulfite, leaf mold, and peat moss can all increase the soil’s acidity over time in areas with alkaline soils. Ask your local nursery for a product to acidify the soil and follow the directions.
Fertilize hydrangeas with acid-loving plant food as needed. You can grow blur-flowered hydrangeas in containers or in contained bed to control the soil composition. Choose pots about 2-4” wider and deeper than those in which they’re growing at the nursery, and make sure they have big drainage holes.
Big-leaf hydrangeas rarely need significant pruning except when stem die back in the winter. At this time, you can cut back 1/3 of the old growth without causing any harm to your shrub. Typically, blooms occur at the stem tips of the previous year’s growth. If the top part of the stem is removed before the terminal bud breaks, then flowers will come from buds farther down the stem. If the whole plant dies to the ground, cut dead stems out and let the shrub regenerate from the base.
In the North (Zones 5), cold winters and late freezes often kill off flower buds set the previous fall. If al the buds are cold-killed, your plant will miss one season’s bloom. If some live the flower buds remain at the bottom of the stem, you should still have flowers, even if you pruned off the dead material. If you want to prune live stems, do that right after flowering, before the shrubs sets new buds for the following year. Pruning after August 1 may cut off the next season’s flower buds.
Pests and Diseases:
Though generally healthy, aphids, mites, scales, leaf spot, rust, and powdery mildew may cause problems for this species.
Best Hydrangea macrophylla Species:
Hydrangea macrophylla ‘All Summer Beauty’ Pink or blue mophead that blooms on new growth and is therefore hardier than most macrophyllas. Zone 5, 3’ to 5’ h and w.
Hydrangea macrophylla ‘Bailmer’ (Endless Summer) has pink or blue mopheads for months on old and new wood.
H. macrophylla ‘Glowing Embers’ (syn. H. macrophylla ‘Forever Pink’) has pink to blue mopheads that begin in late June and continue into fall. 3’ h and w.
H. macrophylla ‘Maculata’ (syn.’Variegata), is grown for its showy variegated leaves with irregular, white margins and gray to green centers. It has lacecap flowerheads with pink or blue fertile flowers surrounded by a ring of white infertile blooms. 3’h and w.
H. macrophylla ‘Nikko Blue’ pink to blue mopheads, more blue in more acid soil, floriferous, and said to be hardier than most, as some may flower on new growth and is the most common mophead form. Grows in Zone 5 , 4’-6’ h and w.
H. macrophylla ‘Red Star’ has red to purple-red lacecaps in alkaline soils; blue-violet in acid soils. Leaves have bright fall color. 4’h and w.
H. macrophylla ‘Setsuka-yae’ (syn. ‘Domotoi’) Double mophead flowers in pink or blue. 5’-6’ h and w.
H. macrophylla ‘Shamrock’ doublepink lacecaps from July turn red and dark pink; violet on acid soils; a compact, long-blooming French hybrid, more refined than many cultivars. 3 1/2’-5’ h and w.
H. macrophylla ‘Tokyo Delight’ Lace-cap with pink fertile flowers surrounded by white florets that age pink. Green leaves with reddish flush in fall. 5’h and w.
H. macrophylla ‘Tovelit’ (syn. ‘Tovelil’) Round, dwarf plant covered with mauve to rosy pink mopheads above narrow, dark green leaves; similar to ‘Pia’ and ‘Glowing Embers’. 3’h and w.
H. serrata (syn. H. macrophylla var. Serrata (mountain hydrangea). Hardier, reaching 4’-5’ h and w. Zone (5) 6.
H. serrata ‘Blue Billow’ lacecap with dark blue, fertile flowers ringed by light blue, sterile florets; in high pH soils, pink florets ring blue fertile flowers. Coppery-red fall color.
H. serrata ‘Golden Sunlight’ New foliage is yellow, maturing to light green; lacecap with pale pink , fertile florets; showy outer florets are white, aging to deep purplish red. 3’ h and w.