Hydrangea
HYDRANGEA
I’VE GROWN HYDRANGEAS HAPHAZARDLY FOR MANY YEARS. I PLANTED MY FIRST SHRUBS IN EAST HAMPTON ABOUT TWENTY-FIVE YEARS AGO. THERE WAS A LONG BORDER ON THE EAST SIDE OF THE ONE-ACRE PLOT THAT NEEDED FILLER UNDER GIANT RHODODENDRONS AND VIBURNUMS, AND SINCE HYDRANGEAS ARE AN IMPORTANT PLANT IN THE HAMPTONS, I BOUGHT A FEW VARIETIES OF MIXED TYPES AND COLORS.
They grew extremely well and fit into the landscape plan very nicely. When I redid that garden a few years ago, I planted only various white hydrangeas throughout, replacing my beloved roses with a different kind of blooming plant (and moving the colored hydrangeas to Katonah). We planted ‘Incrediball’ shrubs, H. paniculata trees, climbing hydrangea (H. petiolaris), many H. macrophylla, ‘Anabelle’ (H. arborescens), lacecap ‘Windermere’, and H. paniculata ‘Grandiflora’. I had specifically planned for strong-stemmed flowers and large-growing shrubs. I have not been disappointed in the least—every shrub has prospered and produced masses of great blooms. All the hydrangeas from East Hampton transplanted very well to Katonah, and I have started a large curved garden on the edges of the Maple Woodland, which is growing well.
I am enjoying the process of starting lots of hydrangeas from cuttings of unusual types and colors that I receive in bouquets from florists. Hydrangeas are very easy to propagate—within three to four years, a shrub grown from a cutting should bloom in the garden. This kind of propagation can be achieved in sand, using a rooting hormone to stimulate growth.
My friend Dan Hinkley travels the world looking for undiscovered species of plants, and he has brought back some lovely delicate flowering hydrangeas in varying shades of mauve and purple from Asia. Dan offers great advice for growing this wonderful shrub: He prefers planting in partial shade, under a high canopy of deciduous trees, feeding heavily once a year. He also suggests growing several different types of this practical plant—oakleaf (quercifolia), mophead (macrophylla), and lacecap hydrangea.
Frank Cabot adapted climbing hydrangeas to his landscape, planting these useful plants at the base of his tallest trees. His forest looks amazing, with the trunks of his trees emblazoned with white flowers protruding from healthy climbing hydrangeas. I have followed his lead and have done this on many trees throughout my garden. The vines enhance the trees, and the trees look so good enshrouded in white flowers.
Most hydrangeas are very good cut flowers. A single mophead in a water glass can turn heads if the flower is oversize, and a great bouquet of paniculata, the way my friend Harry Slatkin displays them, is long lasting and incredibly impactful in a big room.
I sometimes pick just one of each and every type of blue hydrangea in the garden, stick them in small water glasses, and line them up down the center of the breakfast table—how beautiful and informative. (I do this with many of my flowers if I have a good quantity of different types.) And Kevin likes to mix hydrangeas with other flowers for contrast—this results in very successful and beautiful bouquets (as you can see on the following pages).
Because hydrangea stems are naturally tall, they are great foundation flowers and can easily establish the overall shape of anarrangement. Once a few long stems have created a base, nestle the shorter branches into the remaining spaces. Use the different stem lengths to your advantage, to keep the blossoms distinguishable from one another. As a final touch, Kevin added Astilboides leaves into the sides of this arrangement of hydrangeas in a range of similar hues. These massive accents, as well as this vintage ceramic apothecary jar, help to reiterate the scale of this impressive 3-foot-tall display.
Hydrangea macrophylla is a showy bigleaf variety that is excellent in all its possible habitats: on the bush in the garden, cut in arrangements, and left to preserve its blossom in dried form. The name comes from the Greek makros, meaning “large,” and phyllon, meaning “leaf.”
GROWING & ARRANGING
HYDRANGEAS BOAST SHOWY, OLD-FASHIONED APPEAL AND WILL FLOURISH IN ALMOST ANY GARDEN. EASY TO CARE FOR, A SHRUB CAN PRODUCE A PROFUSION OF FOLIAGE AND THE MOST VOLUPTUOUS BLOSSOMS.
Here, a mix of varieties, including ‘Nikko Blue’, show their late-summer blooms in a photograph from my Lily Pond home in East Hampton. I’ve since repainted the trim on the house, from teal to tan. In 2014, some of these shrubs were transplanted to Katonah, where they continue to thrive, but there are still plenty of hydrangeas at Lily Pond.
With an impressive ability to grow 40 to 60 feet high, climbing hydrangea vines cling to walls, trellises, and even trees—here, maples and pines just outside the greenhouse in Katonah.
HOW TO GROW
Hydrangeas are easygoing shrubs that adapt to a variety of soils. They’ll thrive with regular water and at least partial sun. Just make sure to prune according to the variety you’re growing (see Pruning, this page). The result should be big, beautiful blooms.
ZONE Some hydrangea varieties such as the panicle (paniculata) are cool-hardy and can be planted from Zones 3a to 8. Old-growth plants including macrophylla (bigleaf) and quercifolia (oakleaf) can live in climates as cold as Zone 5b. Smooth hydrangea (arborescens) is hardy to Zone 4a.
SOIL While these plants can thrive in nearly any moist, well-drained soil, a soil’s pH level may influence the color of the flowers in the bigleaf group. Acidic soils (pH zero to 7) tend to deepen blue shades, while alkaline environments (pH 7 to 14) brighten pinks and reds. To test the pH of your soil, use a simple kit (available at any nursery). For a more accurate reading, consult your regional extension agency for information on professional soil testing. You can also adjust the soil’s pH at the time of planting—something you might consider if your soil is naturally close to 7, as the neutral levels can sometimes cause muddy purple-hued blossoms. Increase the acidity and encourage blue flowers by adding sulfur (something we do at the farm in Katonah) or a sulfur-based mix called Hydrangea Blueing, available at nurseries. To increase the alkalinity instead, add lime. Blue tends to be the more popular choice, but the pinks and reds can be unusual and lovely. Skip some of the alternative theories you may have heard, like adding pennies to the soil—these remedies don’t always work, and using the proper supplements should yield better, more reliable results.
LIGHT Shrubs will tolerate partial or half shade, but they prefer full sun in cooler climates, especially near the coast. Filtered sunlight is always better for the large leaves, which tend to wilt in bright, midday light. In insufficient light, hydrangeas will become lanky and produce fewer blossoms; they might also be susceptible to powdery mildew.
CHOOSING Most hydrangea plants can be purchased bare-root or in containers (my preference). They should be compact and not blooming, if possible. Inspect plants for signs of wilting leaves or distorted growth patterns, and make sure the plant is not root-bound (see this page).
PLANTING The best time to plant hydrangeas is in spring or fall. Enrich the soil with equal parts compost and aged manure, plus a handful of all-purpose fertilizer. Dig a hole that will accommodate the root-ball and make sure it is at least twice its width. Set the plant in the hole and fill with soil. Give extra water only until the transplant takes hold or if the leaves begin to droop. They grow well in clusters and groups; space plants about 3 to 10 feet apart.
WATERING A popular hydrangea myth is that the name comes from their unquenchable thirst for water. In fact, the genus name was formed from the Greek hydro (water) and angeion (vessel) because the flowers mature into a cup-shaped fruit. Though they do require regular watering, some hydrangeas, including oakleaf and paniculata, are fairly drought-tolerant and ideal for gardens where water conservation is considered. The bigleaf varieties require daily watering.
FERTILIZING Work 1½ to 2 inches of compost or composted manure into the soil every year. Add a balanced fertilizer, and mix with sulfur or lime as appropriate for your desired pH level and color output. (For more on color, see Soil, this page.) On my farm, we also add used coffee grounds weekly—I bring them from the café at my office building in Manhattan. They help add organic matter, as well as acidity—for more of those celebrated “true blue” blossoms.
PRUNING Encouraging blooms is the usual aim of pruning, and knowing the species of a particular variety of hydrangea is the key to success. Generally, the less pruning, the better—so when in doubt, don’t prune.
If your hydrangea sets buds on old (the previous season’s) wood, including most bigleaf cultivars, prune only when the plants are done flowering, in late winter, and remove only the previous summer’s spent flowering stems. Cut out any dead branches along with those that have flowered already, and leave the rest intact. Remontant, or “reblooming,” bigleaf cultivars (such as ‘Endless Summer’, among others) flower on both old and new growth, so no pruning is required. Oakleaf hydrangea varieties also bloom on old wood; remove only dead branches and flowers.
Some species bloom only on new wood, which allows for pruning in late winter or early spring without risk of sacrificing flowers the following summer. These species include paniculata and varieties of arborescens such as the perennially popular ‘Annabelle’.
If you’re not sure whether your hydrangea is old wood, think about when it flowers. Old-wood bloomers begin flowering in early summer and are often done by midsummer. On these plants, next year’s flower buds form in late summer or early fall.
PROPAGATING & TRANSPLANTING Hydrangeas are easy to propagate. Cuttings may be taken from a shrub at any stage of maturity, or even from hydrangeas cut for an arrangement. When the cuttings root, they can be planted outdoors. Start with a stem at least 20 inches long, cut it into 4-inch pieces, and remove the leaves. Dip the ends of the cut stems in rooting compound to stimulate root development. Place the stem in a box of water-soaked sand. Mist frequently and keep outside in the shade, where they will root in four to five weeks. To test, pull gently on the top of the stem. If there is resistance, the roots have taken hold; repot plants in individual containers or transplant them to a shady part of the garden. Plant three to five rooted cuttings close together so that the resulting shrub is a hefty size. It takes about three years for cuttings to grow into shrubs large enough to provide cut flowers.
Transplanting hydrangeas is also a simple process that’s best accomplished in early spring or late fall, when plants are dormant. For easy transport, prune the hydrangeas to half their size and bag them with a small amount of dirt left around their roots. Dig a hole in the new location and feed with a scoop of organic compost, such as Bio-tone.
TROUBLESHOOTING A hydrangea that won’t bloom may have been pruned at the wrong time (see Pruning, this page). Or it may be losing its buds to cold winters or an unexpected freeze. You can replant it in a sheltered area or wrap it in burlap during chilly months. The hydrangea shrubs in Katonah tend to be problem-resistant; watch for mildew, especially in damp, coastal areas, and treat with fungicide if necessary.
‘Glowing Embers’ (right), known as ‘Alpenglühen’, boasts large clusters of pink blooms, and flowers from summer through fall. It makes a great companion for evergreen shrubs and mass plantings under tall trees. Blooms can change from white to pink to deep purple as they mature throughout the season. I also have lacecaps in Katonah, such as this one grown from a rare cutting saved from an arrangement (left).
In the kitchen of my horse stable in Katonah, containers of several varieties of hydrangea are prepared for arranging. After trimming the leaves from the branches, they are returned to their collection containers, which are newly refilled with fresh water. Kevin mixes the different types and sizes of hydrangea among the buckets so as not to crush any of the voluminous flower heads.
HOW TO ARRANGE
CUTTING Hydrangeas don’t cut well when freshly flowering. Wait at least a few weeks after the bloom is completely open, when the blossom has reached its most colorful. The older the bloom, the longer it will last once cut. Cut the flowers in the early morning or late afternoon. To trim stems, use a sharp hand pruner or pocketknife; cut at a diagonal, so that the largest surface area of the stem can be exposed to the water.
MAINTAINING It’s essential to properly condition hydrangeas, or they can wilt within hours. Split the ends of the stems to ensure that they will absorb enough water. If the stem is especially woody, use a small hammer to crush the bottom inch or two. Then try this tip: Place the ends of each stem in boiling water for 30 seconds, making sure that the steam does not burn the flower head. Then plunge the cuttings up to the flower head in cold water. Drape damp paper towels across the tops of the blossoms to cover them completely. Mist the paper towels. Do not allow them to dry out. In four hours, your hydrangeas will be fully conditioned.
Remove any leaves that could end up below the water line, since these will rot and encourage the growth of bacteria and algae. Arrange the flowers in fresh water. Keep out of direct light and away from heat sources.
Rehydrate a bouquet of drying cut blooms by floating them in a sink or tub of cold water for three to four hours. Use sharp pruners to recut and resplit the stems to help them draw more water. Refresh the flowers every one to two days, and the arrangement should look fresh for more than a week.
ARRANGING Hydrangea petals are somewhat inconspicuous, but the sepals—the usually unobtrusive leaf-like structures that surround a flower—are bright and showy. And because sepals do not drop off as quickly as petals do, hydrangeas are ideal subjects for long-lasting fresh arrangements. Kevin prefers to design with paniculata, which he finds very resilient and easy to work with. They keep their foliage better than macrophylla. Often, simpler is better: Let the hydrangeas form a mass of color on their own, or complement the full, rounded shapes of their blossoms with broad hosta leaves.
Bigger vessels are better for these oversize blooms on tall stems, to keep the sense of proportion and to offer support. However, if you cut the stems down, you can use a low, wide vase or bowl. For these arrangements, use chicken wire to secure the stems, as it’s easier to manipulate (see this page).
Kevin prepares to insert a giant Astilboides leaf into a grand-scale arrangement of hydrangea (pictured on this page), playing up the juxtaposition of bloom and foliage.
Late-afternoon light illuminates the breathy blossoms of an all-white hydrangea arrangement with hints of green, mirrored in an Art Deco French painted cast-iron urn. White H. paniculata’s dainty sepals make for an airier display than its denser cousins; Kevin removed all foliage to keep the focus on the flowers themselves. He placed young paniculata blossoms sparingly throughout the arrangement to create space and lift among the weighty hydrangea blooms. A smaller, breathable bouquet like this one allows for an approachable display that can be placed anywhere.
Arranged in a white ironstone tureen with a flower cage, just a few boughs of ‘Blaumeise’hydrangea and wine-colored mophead ‘Oregon Pride’ form a color-saturated bouquet. The natural shape of the blossom lends itself to a simple dome on short stems.
A lofty, large-scale display adorns a Scandinavian table on the second-floor landing in East Hampton. It’s composed of the panicle, oakleaf, and mophead hydrangea varieties that line the property; the flowers thrive in coastal areas and they seem to love the rich Long Island soil. Kevin arranged the tall, slender boughs of paniculata to appear as if they’re jumping from the vase, with denser macrophylla as a base. To balance the height and obscure the stems, he tucked ‘Autumn Snow’ clematis vines into the top of the vessel and draped them around the base.
Kevin arranged green and white mophead and paniculata hydrangeas, some with violet edges, in an antique limestone garden urn for a dramatic addition to a grand entryway. Perfect for a formal event, the hydrangeas evoke the richness of Flemish paintings, mingling with broad hosta leaves and cascades of snowberries, jasmine, and amaranth. Though not expensive flowers, either to grow or to purchase, they can nevertheless create a lush, luxurious, and over-the-top arrangement. To assemble, use a ball of chicken wire to hold the stems. Start with the tallest hydrangea blossoms to create fullness and height; insert shorter stems at outer edges and add foliage sparingly on one side. Add graceful vines of jasmine and trailing amaranth around the rim at the end to embrace the asymmetrical arrangement.
An arrangement of dense hydrangeas in a pewter compote brings out the colors in a French ticking fabric tablecloth. Use floral putty to secure a cage frog to the bottom of the vessel, then add stems of various heights to stagger the bulbous blossoms and prevent them from crushing one another. Leave some of the hydrangea foliage intact to allow subtle pops of green to peek through the florets.