Certain plants have the ability to conjure up memories, emotions and feelings of special times and special places. For many the hydrangea’s fairy-tale blue clusters remind us of carefree summer days spent lazing on the Cape, where the showy blooms dress up cottage gardens. We plant hydrangeas in our own beds for the restful feelings they inspire, as well as for the beauty of their opulent midsummer blooms.
Although the most familiar, the blue hydrangea, or more properly, Hydrangea macrophylla, is just one of over a hundred known cultivars of Hydrangea. Along with Hydrangea macprophylla, other varieties that do well in our area include H. paniculata grandiflora and H. anomola petiolaris. Hydrangeas are generally easy to grow, are hardy to zone 6 or in areas of temperate winters, and require little care or maintenance.
Hydrangea macrophylla is divided into two main groups: hortensias, which feature the globular blue, pink, red and white blooms of Cape Cod fame, and lacecaps, which are distinguished by flatter clusters of sterile, papery petallike sepals. Both types can be propagated by suckered division. They are long-lived plants that are relatively trouble free.
As a group, hortensias feature thick, erect, and unbranched stems that easily reach full height in just a single season. Their glossy foliage is striking in its own right, but the plant is characterized by its showy round clusters, which range in color from blue to white to pink, the color varying with the pH level of the soil. Here in the Northeast, our acidic soil (pH range of 5.5 or lower) gives blooms a blue tone. As the soil pH neutralizes, the color of bloom graduates to white, then pink and finally to a near red shade. Adding aluminum sulfate to lower the soil pH results in blue blooms, while raising the soil pH with ground limestone produces pink/red hues. The plants prefer a sunny to partly sunny location, with moist soil that is rich in organic matter.
In recent years, lacecaps have seen a resurgence in popularity as an old-fashioned favorite. Like hortensias, they prefer a sun to part sun and rich, moist soil. The plants benefit from having the stems, that have flowered, removed while the plant is dormant. A more vigorous thinning (as opposed to pruning, or cutting back) will produce larger flower clusters.
Another old-favorite is the Hydrangea paniculata grandiflora or “pee gee” hydrangea. This fast-growing treelike shrub features a mop-head-like flower cluster in mid-to-late summer. The flowers open to white in summer, turn a pinkish hue in September and fade to tan by fall. They are outstanding as a dried flower, sometimes lasting years in dried arrangements. Because pee gee hydrangeas bloom on new wood, prune hard when the plant is dormant to produce larger flowers the next summer. An easy to grow plant, it is extremely long-lived and has been a favorite of gardeners for generations.
The climbing hydrangea, or Hydrangea anomola petiolaris is another versatile performer. Clinging to tree trunks or brick by aerial roots, it can grow to 60 feet, and once established, this plant takes off! Its fragrant white flowers nearly cover it in summer and it does well in the shade of most deciduous trees. Planted at the base of an elm or an oak, this climbing hydrangea will wind its way up the trunk and provide spectacular color all summer long.