Hydrangeas have exploded in popularity in recent years, thanks to their spectacular, long-lasting flowers in blue, purple, pink, red, or white. Close inspection reveals that each flower cluster is composed of tiny, fertile, seed-producing flowers on the inside, and large, showy, sterile flowers on the outside. 'Mopheads' feature large, rounded or conical clusters of sterile flowers that hide the fertile flowers inside. 'Lacecaps' display flattened clusters of fertile flowers ringed by showy sterile flowers. Fertile and sterile flowers may be two different colors depending on soil.
These plants are famed for the ability of their flowers to change colors due to soil conditions, but this only occurs in three of the listed speciesH. aspera, H. macrophylla, and H. serrataand for selections with flowers of blue, purple, pink, or red. Strongly acid soil (pH 5.5 and lower) produces the bluest colors; alkaline soil (pH 7.1 and above) produces pink and red flowers; and slightly acid to neutral soil (pH 6.5 to 7) produces a mix of blue, pink, and purple flowers. Soil pH does not affect white blooms in these species. It also doesn't cause the color change in species like H. paniculata and H. quercifolia; their blooms typically change from white to rose as they age.
To acidify the soil, sprinkle aluminum sulfate or garden sulfur around your hydrangea, and water it in. To make the soil alkaline, do the same with lime. Don't expect overnight change. The change could take a year and require repeated applications.
H. anomala petiolaris. CLIMBING HYDRANGEA. Deciduous vine. Zones US, MS, LS; USDA 6-8. Native to Russia, Korea, and Japan. Truly one of the world's most beautiful vines, considering its flowers, foliage, and structure. Can climb to 60 ft. or more using clinging aerial rootlets. Green, 2- to 4-in., heart-shaped leaves turn soft yellow in fall. Mature vine develops a picturesque, woody scaffold of short branches held out from the support. Flat lacecap clusters of white flowers 610 in wide appear from late spring into summer. Some vines may take 10 years to start blooming. Needs little pruning.
H. arborescens. SMOOTH HYDRANGEA. Deciduous shrub. Zones US, MS, LS, CS; USDA 6-9. Native from New York to Iowa, south to Florida and Louisiana. Not much to look at in the wild; offers small clusters of creamy white, mostly fertile flowers in May or June. Named selections, listed below, are far superior. Prune in late winter. Severe pruning produces much larger blooms, but fewer of them. Can take full sun.
'Annabelle'. Classic all-time favorite, famous for huge, rounded clusters of sterile, white flowers up to a foot across over a long period. Grows about 4 ft. tall and wide.
'Bella Anna'. Often called 'the pink 'Annabelle',' although flower clusters are smaller. Rosy pink blooms held upright on sturdy stems. Grows 34 ft. tall and wide.
'Incrediball' ('Abetwo'). Offspring of 'Annabelle' with even larger clusters of white blooms.
'White Dome'. Dome-shaped clusters of sterile flowers to 10 in. across. Grows 5 ft. tall and wide.
H. aspera. Deciduous shrub. MS, LS; USDA 7-8. From eastern Asia. Imposing shrub to 1012 ft. tall, spreading nearly as wide. Dark green, velvety leaves to 10 in. long, 4 in. wide. Rather flat, 10-in. lacecap flower clusters contain purplish white to pink fertile flowers surrounded by 1-in. white, pink, or purple sterile blooms. Prune in late winter. Happier on the West Coast than in the South. Not a hydrangea for the beginner. 'Plum Passion' has dramatic purple foliage and insignificant flowers.
H. macrophylla. FRENCH HYDRANGEA, BIGLEAF HYDRANGEA. Deciduous shrub. Zones US, MS, LS, CS; USDA 6-9. From Japan, not France (many early selections originated in France). The South's most popular hydrangea. Symmetrical, rounded shape; grows 38 ft. tall and wide. Thick, shiny, coarsely toothed leaves to 8 in. long. Blooms first appear in May or June. Does not like drought; usually the first plant in your yard to wilt in summer.
Hundreds of named selections exist. Those listed below represent our top picks. Some bloom once a year for several weeks on the previous year's growth. Others bloom repeatedly on both old and new growth, as long as plant is kept actively growing in summer through frequent watering. Flowers for most can be either blue or pink, depending on soil pH.
'All Summer Beauty'. Mophead. Repeat bloomer. Grows 45 ft. tall and wide. Dependable.
'Ami Pasquier'. Mophead. Once bloomer. Maintains deep-pink color in all but the most acidic soils, where it turns purple. Grows 45 ft. tall and wide.
'Ayesha'. Mophead. Once bloomer. Large clusters of uniquely cupped petals look like little buttons. Glossy foliage. Grows 6 ft. tall and wide.
'Big Daddy'. Mophead. Repeat bloomer. Gigantic blooms up to 14 in. across. Glossy foliage. Grows 56 ft. tall and wide.
'Blue Wave'. Lacecap. Once bloomer. Old, reliable choice. Glossy foliage. Grows 6 ft. tall and wide.
'Blushing Bride'. Mophead. Repeat bloomer. Blooms emerge white, turn blush pink, then finish deep rose. Grows 4 ft. tall and wide.
Cityline series. Mopheads. Compact, sturdy-stemmed plants that need no pruning. Variety of colors. Mildew resistant. Grows 3 ft. tall and wide.
'Dooley'. Mophead. Once bloomer. Cold hardy selection named for Vince Dooley, legendary football coach of the University of Georgia Bulldogs. Flower buds cold hardy to single digits. Grows 6 ft. tall and wide.
'Endless Summer'. Mophead. Repeat bloomer. The selection that turned the hydrangea world on its head, thanks to repeat blooms and clever marketing. Grows 4 ft. tall and wide.
Forever & Ever series. Mopheads and lacecaps. Repeat bloomers. Similar to 'Endless Summer' Series, but with larger flower clusters and larger individual florets. Blue, pink, white, red, and bicolor plants. Grow 4 ft. tall and wide.
'Fuji Waterfall'. Lacecap. Once bloomer. Double, white, sterile flowers on long stems appear to dance above the flower heads. A showstopper. Grows 34 ft. tall and wide.
'Gnrale Vicomtesse de Vibraye. Mophead. Once bloomer. Like 'Dooley,' flower buds very cold hardy. Great for cut flowers. Grows 7 ft. tall and wide.
'Lanarth White'. Lacecap. Once bloomer. Compact, very dependable. Grows 34 ft. tall and wide. White, sterile flowers.
'Madame Emile Mouillre'. Mophead. Usually blooms once, but may repeat. Widely considered the best white mophead. Grows 6 ft. tall and wide.
'Merritt's Supreme'. Mophead. Once bloomer. Keeps deep pink color in all but most acid soils, where it turns royal purple. Grows 34 ft. tall and wide.
'Mini Penny'. Mophead. Repeat bloomer. Compact-growing seedling of 'Pennymac'. Grows 34 ft. tall and wide. Good in containers.
'Nikko Blue.' Mophead. Once bloomer. Cold-hardy flower buds continue the popularity of this dependable old favorite. Grows 5 ft. tall and wide.
'Penny Mac'. Mophead. Repeat bloomer great for cut flowers. Named for Penny McHenry, founder of the American Hydrangea Society. Grows 6 ft. tall and wide.
'Pia'. Mophead. Once bloomer. Charming dwarf great for containers. Pink or purple flowers. Grows 3 ft. tall and wide.
'Twist-n-Shout'. Lacecap. Repeat bloomer. Red to burgundy fall foliage. Grows 35 ft. tall and wide.
H. paniculata. PANICLE HYDRANGEA. Deciduous shrub or small tree. Zones US, MS, LS, CS; USDA 6-9. Native to Japan and China. Upright, spreading growth to 1020 ft. tall and wide, sometimes larger. Recent breeding efforts have resulted in smaller plants, more manageable in the garden. Medium to dark green leaves, oval and pointed, 36 in. long, turn light yellow in fall. Flowers begin as elongated clusters of greenish white buds in early summer, opening to 4- to 8-in.-long cones of white, sterile flowers hiding fertile flowers within. Blooms age to a tawny pink, making a show that lasts for months. This is the toughest, most adaptable species listed here. Can take full sun. Prune in late winter. The plain species is seldom grown in favor of the following recommended selections.
'Grandiflora'. PEE GEE HYDRANGEA. An old favorite, sometimes called the crepe myrtle of the North for its cold hardiness and summer blooms. Coarse-textured plant can be trained into a 25-ft. tree or maintained as a shrub. Huge, rounded flower clusters to 112 ft. long.
'Limelight'. White, upright blooms sometime age to deep pink. Grows 610 ft. tall. Extremely popular and deservedly so.
'Little Lime'. Dwarf version of 'Limelight', growing 35 ft. tall.
'Pink Diamond'. Pink buds open to cream-colored flowers that gradually darken to rosy red. To 10 ft. tall.
'Pinky-Winky'. Flower heads emerge white in summer and elongate. Blooms turn pink with age, creating a bicolor effect. To 8 ft.
'Tardiva'. Late-blooming form with conical flowers that appear in August and September. To 10 ft.
'White Diamonds'. Compact grower to 56 ft. tall and wide. Upright flower clusters to 8 in. long open white, then age to light green.
H. quercifolia. OAKLEAF HYDRANGEA. Zones US, MS, LS, CS; USDA 6-9. Native to the Southeastern U.S. The state wildflower of Alabama. Broad, rounded shrub to 6 ft. tall, 8 ft. wide. Handsome, deeply lobed, 8-in.-long leaves resembling those of oaks turn scarlet and crimson in fall. Elongated clusters of white flowers appear in late spring and early summer and age to rose. Prune in early summer. Favorite selections include:
'Alice'. Large flower clusters up to 14 in. long. Grows 12 ft. tall and wide.
'Harmony'. Huge, heavy clusters up to 12 in. long of mostly sterile flowers weigh down the branches. To 10 ft. tall.
'Jetstream'. Dense, compact grower (56 ft. tall, 45 ft. wide), with strong stems. Heavy bloomer; good orange-red fall color.
'Pee Wee'. Dwarf form with leaves and blooms about half the size of the species. Grows 34 ft. tall, 6 ft. wide.
'Sike's Dwarf'. Dwarf form growing 2 ft. tall, 4 ft. wide.
'Snowflake'. All-time favorite discovered by Alabama nurseryman Eddie Aldridge. Nodding blooms up to 15 in. long. As blooms age, new white florets emerge atop older ones that have turned dusty rose, creating a double-flowered, bicolored effect. Grows 10 ft. tall and wide.
'Snow Queen'. Showy clusters up to 8 in. long stand upright atop the shrub. Grows 6 ft. tall and wide. Superior selection.
H. serrata. MOUNTAIN HYDRANGEA. Deciduous shrub. Zones US, MS, LS; USDA 6-8. Native to Japan and China. Resembles H. macrophylla but is more compact and graceful, with smaller leaves. Also blooms earlier. Grows 36 ft. tall and wide. Many selections develop burgundy fall foliage. Prune in early summer.
'Akishino-temari'. Mophead. Compact shrub to 3 ft. tall and wide. May rebloom in fall.
'Beni-gaku'. Lacecap. Once bloomer. Flowers open white and age to red. Handsome, deep green foliage. Grows 4 ft. tall and wide.
'Blue Billow'. Lacecap. Dependable once bloomer with cold hardy flower buds. Grows 4 ft. tall, 6 ft. wide. One of the deepest blues when grown in acid soil.
'Bluebird'. Lacecap. Flowers off and on through summer. Leaves turn coppery red in fall. Grows 34 ft. tall and wide.
'Blue Deckle'. Lacecap. Like 'Bluebird,' blooms off and on all summer. Red fall foliage. Grows 4 ft. tall and wide.
'Kurohime'. Lacecap. Once bloomer. New stems are deep purple. Grows 4 ft. tall and wide.
'Preziosa' (H. macrophylla 'Preziosa', H. 'Preziosa'). Mophead. Once bloomer. Compact growth to 34 ft. tall and wide, with dark maroon stems. Cold hardy.
'Purple Tiers' ('Miyama yae Murasaki'). Lacecap. Once bloomer. Layers of double, sterile flowers, purple in acid soil, are quite beautiful. Grows 4 ft. tall and wide.
'Woodlander'. Lacecap. Once bloomer. Green leaves age to dusky purple. Grows 4 ft. tall and wide.
Moist, well-drained, fertile soil is best. Prune hydrangeas that bloom on new growth in late winter. Prune those that bloom on last year's growth as this year's blooms start to fade. Prune repeat bloomers anytime. Keep in mind that most hydrangeas need little pruning other than removing dead wood in spring.