pruning and transplanting tips
Last spring, at a mid-April pruning workshop held at Heritage Museums and Gardens, Joan Brazeau, the current president of the Cape Cod Hydrangea Society, shared hints for hydrangea pruning with a large group of gardeners of all abilities. Armed with big loppers for cutting out large canes right down to the ground as well as smaller pruning “snips” for removing last year’s dead flowers, Brazeau led the group around Heritage’s numerous hydrangea plantings, including several right at the main entrance.
Brazeau, whose Yarmouthport gardens flourish with more than 75 hydrangeas, introduced the group to Mary Kay and Mal Condon, owners of the well-known and respected Nantucket Hydrangea Farm (hydrangeafarm.com), who helped answer questions. Standing before a grouping of mopheads that looked like a sad collection of dead sticks, Brazeau pointed out the just-emerging pairings of buds clustered along several canes. “Before I start, the first thing you need to know is that everyone who prunes hydrangeas needs sharp pruning shears,” said Brazeau. Wielding a pair of clippers, she demonstrated the best way to prune off last year’s blossoms, making a cut just above a pair of outward facing buds on a healthy cane.
“Do this all over the shrub,” said Brazeau, cutting off all of last year’s flowers above a pair of buds and demonstrating the importance of removing any spindly canes, or those criss-crossing each other. “The good news is that hydrangeas really require very little care,” said Brazeau. “Hydrangeas don’t even really need pruning—in the wild, hydrangeas are not pruned and the shrubs still bloom.” However, Brazeau explained that all kinds of varieties—from the aborescens to the paniculata varieties—get a good jump-start in the spring by pruning out three to five of the largest canes.
“Take out your big loppers and cut the stalks right down to the ground,” said Brazeau, drawing gasps from the more tenderhearted gardeners in the group.
She explained that any completely dead canes (which have a much whiter look and also snap off with ease in your hands) should also be cut to the ground. “This is much easier to do before the leaves appear and it will increase air flow in the shrub as it begins to bloom,” said Brazeau, noting that both paniculatas and arborescens can be pruned down to 18 to 24 inches each year if desired.
Brazeau noted that the latest trend in hydrangeas is the development of more “remontant” varieties, or those that can bloom on both new and old wood. Varieties such as the popular Nikko and Endless Summer hydrangeas fall into this category.
When asked if hydrangeas can be transplanted in the spring, Brazeau noted that hydrangeas can be moved in either the early spring, or the early fall. “Hydrangeas are very hardy and can be moved at either time of year, but they need to be in a place where they are comfortable,” said Brazeau. “If you transplant your shrub in April, you probably won’t get any blooms that summer—but next year, your hydrangeas will thank you with lots more blooms.”
Moving onto a large row of “Limelights” bordering a long picket fence near Heritage’s gift shop, Brazeau encouraged all the volunteers to jump in and start pruning. “These are paniculatas, which bloom on new wood and need to be pruned lightly,” said Brazeau, noting that the “Limelight” planting is a favorite with Heritage visitors. “This garden is photo op number one,” said Brazeau. “It is just beautiful with these ‘Limelights’ full of thick foliage and huge white blooms, bordered with purple Russian Sage perennials and some colorful mophead hydrangeas.”
“‘Limelights’—and almost all hydrangeas—do not like a lot of high, hot sun,” Brazeau continued. “The perfect spot for most hydrangeas is one with morning sun and afternoon shade.”
Leading the group to the Cape Cod Hydrangea Society’s display garden, Brazeau pointed out several new shrubs planted the previous fall, which were surrounded in chicken wire stuffed to the brim with pine needles. “We put baskets around those that are young, or especially tender, in December,” said Brazeau.
Asked about fertilizing, Brazeau said she gives her hydrangeas a dressing of a fertilizer like 19-6-12 to encourage blooms in the early spring, explaining that fertilizing should end by mid-July. “The main thing about hydrangeas is that they love water,” said Brazeau, noting that her own dozens of hydrangeas are well watered with a comprehensive drip irrigation system that she runs three times a week for 45 minutes. “If you don’t have a drip system, be sure to thoroughly water the roots of the hydrangeas, not the flowers,” she explained. “Water the shrubs at least three times a week with a good solid soaking—early morning watering is always best.”
When asked how to change the color of a hydrangea, Brazeau made a joke about a “Blushing Bride” hydrangea, a pale mophead with a pinkish hue. “This bride was a little frigid and needed some warming up,” said Brazeau to loud laughter. “She needed some lime, which turned her a warm pink.” Brazeau explained that lime could be applied to a hydrangea’s roots to increase pink color, whereas aluminum sulfate enhances the blue tones of shrubs. “Aluminum sulfate can really make a big difference to the blue color of a hydrangea,” said Brazeau. “It will take a season for the color to change, but next year you’ll say, ‘Wow! Now that’s a really blue hydrangea!’”
“At the Hydrangea Society, we try to promote all kinds of hydrangeas that will do well on Cape Cod and the Islands,” Brazeau concluded. “Not every hydrangea has to be an ‘Endless Summer’—although it’s probably appropriate that this variety is what most people who come here love best.”