BOOMING HYDRANGEAS
This has been a wonderful year for hydrangeas. I see the evidence in my own garden, as the ‘Nikko Blue’ mopheads show off their billows of cerulean flowerheads. It may be just a trick of the light, but the one in the shadiest spot has the bluest flowers. My large oakleaf variety, Hydrangea quercifolia, is at least six feet tall and eight feet wide and covered with huge cones of creamy flowers, now turning to pink as they age. Its offspring, which I transplanted to the back yard, is also covered in bloom and will undoubtedly be as large as its parent within a few years. The various smaller hydrangeas are booming as well and a potted specimen that has never flowered before has produced three big, pink flowerheads.
I would brag excessively about all of this, if it weren’t also happening in every yard in my town. People who complained about a dearth of flowers last year pull neighbors in off the streets to see this year’s bounty. Even the attractive but finicky variegated hydrangeas, which frequently produce no flowers at all, are sprouting blossoms. The lacecaps this year are larger and lacier. I predict that when the “peegee” or Hydrangea paniculata grandiflora shrubs bloom later in the summer, they will exceed expectations as well.
Why is this happening? Have the hydrangea stars suddenly aligned themselves? Hydrangeas have become wildly popular over the last fifteen years, but their ways can be mysterious–even to those who know them well.
There are ways–at least theoretically–to produce abundant flowers. First it is important to give the plants a good start by siting them properly. Some catalog vendors would have you believe that hydrangeas can flourish in deep shade. This is a myth. Depending on the species and variety, hydrangeas thrive in light or dappled shade or even part sun/part shade. Too much direct sunlight will burn leaves and dry up plants, especially in the South.
Hydrangeas lap up water like overheated Huskies, but don’t like standing water on their roots. Mulching is very helpful in conserving resources, as is supplemental irrigation in hot weather. If the leaves are drooping, add water; the plant should perk up quickly. Plants that have to eke out an existence with less than optimal moisture tend to produce fewer and smaller blooms.
Pruning at the wrong time or with too much zeal will reduce or eliminate blooms. Most hydrangeas bloom on old wood and some newer varieties bloom on old and new wood. “New wood” is this year’s growth. “Old wood” is anything that is not this year’s growth. The best time to prune any flowering shrub is right after it blooms. For hydrangeas that means fall. To maximize bloom for the following spring, prune any dead branches down to the ground. Prune other growth to the first node, which is the first nodule on the stem where a leaf will sprout. Make a 45 degree angled cut above this node and repeat the process on the rest of the plant. If you have done this right, you will have shaped the plant without sacrificing next year’s blooms.
There are, of course, exceptions to the “if you have done this right, you will have blooms” rule. The big exception has to do with something that is completely out of your control–weather. A hard frost at the wrong time can negate the value of good siting, ample moisture and intelligent pruning. The worst thing for the average hydrangea is a mild winter followed by an abnormally harsh and sudden spring freeze. The tender buds freeze and that is the end of flowers for the season, unless the plant is one of the new-fangled varieties that can bloom on new wood. If you have one of those, the blooms will be reduced but not eliminated. This “death by sudden freeze” phenomenon also explains why some hydrangeas produce blooms on only one side of the shrub in certain years. It is the reason why a hydrangea in one part of the yard will produce abundantly while an identical hydrangea on the other side of the property yields no flowers. Chances are the shrub with blooms on only one side was partially protected from a harsh freeze, either by proximity to a structure or to other plants. The same principle holds true for the two hydrangeas in different parts of the garden. One was almost certainly more exposed than the other. Sometimes you can prevent bud death by covering the exposed shrubs when a hard frost is expected. Most people, however, don’t think of this until the hydrangeas fail to bloom in the summer. This is one of the many reasons why gardeners, like sports fans, always hold out hope for next year.
This year, in this place, the forces of nature worked in harmony. We hydrangea lovers will have plenty of flowers to cut, to dry and to photograph for reference next year when conditions may not be as favorable.
Hydrangeas of various types are available in most nurseries and garden centers. For interesting and unusual selections, try Hydrangeas Plus, P.O. Box 389, Aurora, OR 97002; (866) 433-7896; www.hydrangeasplus.com. Catalog $4.75, refundable with first order.