In the peak of summer when the perennial garden looks long in the tooth, the handsome hydrangea bursts forth to inject new life into a tired landscape. Equally at home in either a formal or cottage garden some varieties may start their flower show as early as June and carry on well into September, so this shrub should be featured in every garden for both its versatility and timely blooming. If you treat them well and prune them correctly they will reward you with a explosion of flowers all summer long year after year.
Hydrangeas all prefer rich, moist soil with good drainage, and most relish morning sun followed by dappled afternoon shade; too much sun and they will fry and too much shade and they won’t flower. In early spring give them a dose of fertilizer specifically developed for hydrangeas or one with a high middle number, that is, more phosphorus than nitrogen or potash, and repeat the dosage in mid-summer. As for the pruning, the optimum time depends on the species of hydrangea – whether it blooms on old wood, that is last year’s growth, or new wood, this year’s stems.
Old Wood Bloomers
As an example, H. macrophylla, or Big-Leafed Hydrangea blooms on old wood so it should be pruned right after flowering, unless it is a repeat bloomer flowering on both new and old wood such as the Endless Summer® Collection (more about these cultivars later) which can be pruned any time. The flowers of the Bigleaf Hydrangea are either mopheads with big showy pompom flowers or lacecaps, more delicate flowers whose centers resemble tiny berries surrounded by a ring of petals. Both types generally range in color from pink to blue (although some white cultivars do exist), and the gardener can deepen or even change the color by altering the soil pH, that measure of the soil’s acidity or alkalinity. If it’s cool blue flowers you prefer increase the acidity of the soil by adding aluminum sulfate, or if you favor the hot pinks and reds add lime to augment the soil’s alkalinity. For ease of cultivation and a profusion of mophead flowers, two outstanding choices are ‘Nikko Blue’ and ‘Forever Pink.’ If the delicacy of the lacecap varieties is more appealing choose ‘Blue Billow’ or ‘Sunset’ whose vivid scarlet blossoms will light up your summer garden.
Shaking up the hydrangea world in the past ten years was the introduction of the Endless Summer Collection®, Big Leaf Hydrangeas that boast bloom times extending from June through September. Developed by Bailey’s Nursery and Dr. Michael Dirr, two outstanding mophead members of the collection are The Original®, a periwinkle blue (or pink, if you choose), and Blushing Bride® whose white flowers take on a pink cast (or Carolina blue, if you prefer) as they mature. Twist-n-Shout®
represents the Collection’s summer blooming lacecap variety, and all three hydrangeas in the collection prefer light shade and regular water; if allowed to dry out they will not rebloom.
Another species that should be pruned after flowering, the Oakleaf Hydrangea,
H. quercifolia, is prized as much for its stunning dark green foliage as its pendulous white blossoms. As the nights lengthen the leaves turn a deep wine color, and the creamy flowers, first appearing in early summer, fade to rusty red. Before winter blows in and shuts down your garden, gather an armful of blossoms and dry them indoors; unlike many of the other members of the hydrangea family, these flowers will not shatter when used in dried arrangements. Performing well in part shade, a choice cultivar, ‘Snowflake’, is decked out in double blossoms from spring all through summer. For a more upright variety chose the lovely ‘Snow Queen’ whose smaller single flowers are light and airy. Regular water is a must as it is with the other family members.
If you have a rock wall that needs softening, the Asian native
H. anomala petiolaris, Climbing Hydrangea, is a natural choice, and for this rugged beauty it doesn’t matter whether you plant her in full morning sun or deep shade. Even though she is hardy in USDA Zones 4-8, protect her from the blistering afternoon sun in Zone 8. Studded with small creamy lacecap flowers in early spring this rambunctious climber is covered with handsome heart-shaped leaves set against reddish-brown peeling bark. Although she seldom needs pruning, if you must tame her do so in early summer after flowering.
New Wood Bloomers
An ideal candidate for northern gardens H. arborescens, or Smooth Hydrangea, blooms on new wood so even if a rough winter takes it down, it will bounce back and produce masses of flowers on its young stems. Hardy in USDA Zones 3-9 this Eastern native prefers part shade, is not fussy about soil, and unlike most of its relatives can tolerate dry conditions once established. The old-fashioned ‘Annabelle’
has been a gardener’s favorite since 1962 but is being rapidly upstaged by the newly available ‘Incrediball’® which boasts big fat flowers that open green in the spring, change to white in summer and take on a greenish tint as the days shorten. Unlike the flowers of ‘Annabelle’ that tend to flop over under their weight the upright stems of ‘Incrediball’ can support its massive blossoms. To stimulate reblooming deadhead spent flowers religiously.
Another tough beauty, H. paniculata can tolerate urban pollution and severe winters, and the variety ‘Grandiflora’, commonly known as Pee Gee Hydrangea, is a landscaper’s favorite. Sometimes grown as a shrub,
this is the only hydrangea that can be shaped into a tree form, and although garden aficionados dismiss Pee Gees as “common” the sight of a stately tree laden with creamy cone-shaped flowers fading to pink as they age draws forth grudging admiration from even the most jaded horticulturist. Another choice cultivar is ‘Limelight’
whose flowers sport a greenish tinge. To ensure constant blooming through the summer site all H. paniculatas in full sun except the deep South where they need afternoon protection.
One final pruning note: if it’s big flowers you’re after reduce the number of stems when you are cutting back; the hydrangea’s energy pie is just so big, and it can either direct its growth into many smaller flowers or fewer big flowers. The choice is up to you.
White Flower Farm
Spring Hill Nursery