Ah, Hydrangea. A flower that brings to mind old lace and lazy summer evenings. A welcome sight when many of the other shrubs in the landscape have finished blooming. They come in a variety of sizes and flower shapes, so there’s sure to be one that fits in your garden!
The Smooth Hydrangea (H. arborescens) is the traditional “snowball bush” found in almost everybody’s grandmother’s garden. Very easy to care for, this sometimes spreading shrub has enormous white flowers in summer. A beautiful plant for a border or accent planting, and is much hardier than most varieties of Bigleaf Hydrangea.
Hydrangea paniculata, the Panicle Hydrangea, is king of the late summer garden. Growing to nearly 15 feet tall (after many, many years), big white blossoms open in late July, then turn pink, and last through the first couple light frosts. There are over a dozen cultivars available, the most popular being ‘Grandiflora’, more commonly known as ‘PeeGee’. Blossoms can be clusters of entirely sterile, large flowers or a mix of sterile and smaller fertile flowers, making a lacecap-style display.
If the Panicle Hydrangea is the king, the Oakleaf Hydrangea (H. quercifolia) is queen. It is also one of the few hydrangea that are native to the United States (H. arborescens being the other). A more delicate species, well suited to growing in partial shade, this plant has four seasons of landscaping interest. Uniquely shaped medium green foliage provides a backdrop for its beautiful white and pink blossoms from late summer into fall, when the foliage turns shades of burgundy and gold. The branching structure is beautiful to see in the winter, but it is a good idea to keep these plants sheltered from the drying winter winds.
The most popular and colorful Hydrangea for summer is the Bigleaf Hydrangea (H. macrophylla). Bigleaf Hydrangea is a fascinating flowering shrub, one of only a few plants that serve as a soil pH indicator. Acidic soils will turn the blooms purple or blue, while alkaline soils will produce pink flowers. To turn your hydrangea blue, treat the soil and plant with a fertilizer formulated for acid-loving plants. Garden Sulfur is another acidifier that will more quickly change the pH of your soil, as well as promote growth and deep greening of leaves. If you desire pink Hydrangea blooms, fertilize with a general garden fertilizer, and it may be necessary to add a small amount of lime to the soil in the spring.
The ‘Endless Summer’ line of Bigleaf Hydrangea has been a godsend to us here in the Northeast. No longer do we have to be frustrated with a beautiful leafy hydrangea bush that never blooms! ‘Endless Summer’ (the original blue or pink), ‘Blushing Bride’ (white that turns pink), and the new ‘Twist n Shout’ (blue or pink lacecap) all bloom on both new and old growth, so no matter how cold the winter, we will always have big, beautiful blossoms in midsummer!
If your Hydrangea is not blooming, the most likely culprit is our cold Maine winters. Older varieties of this plant blossom on 2-year old wood, which can pose a problem for those of us in the northeast. ‘Nikko Blue’, ‘All Summer Beauty’, and ‘Pink Beauty’ are some varieties that are only hardy as far down as the snowline. Cold winters will often damage those branches that remain above the snowdrifts, resulting in a beautiful leafy shrub that will never bloom. This can be alleviated somewhat by the judicious application of mulch hay and burlap wraps before the snow flies. After the snows of winter come, shovel as much as possible right on top of the plant. We have natural, free insulation that falls from the sky for 5 or 6 months; we should use it. The trick is to keep the buds insulated so they freeze and stay protected from harsh, drying winter winds.