Who doesn’t love hydrangea? A quick drive around the neighborhoods of Bloomington will bring testimony to the popularity of this plant. At Hilltop Gardens the hydrangea row is beautiful with its abundant heads of snowball type blooms bobbing in the warm August winds. While there are disagreements about the number of varieties of hydrangea, the most common species are big leaf, smooth, panicle, oakleaf, climbing and mountain.
Hydrangea is a prolific bloomer that offers a summer show that lasts into fall. An Illinois native species, Hydrangea arborescens, also known as “Annabelle” or limelight hydrangea and pictured here, sprouts abundant branches from a deciduous shrub that grows 3-4 feet tall. It sports large, dark-green, broad, sharp-toothed leaves that taper to a point. Its large, slightly- domed balls of flower clusters first bloom in lime-green, then change to a creamy-white.
Hydrangea enjoys full sun in the morning and shade in the afternoon, but it grows well in filtered light, along a fence, or in a wooded area; it is highly versatile. Check the instructions for the cultivar you are planting to find out what conditions it tolerates. If your hydrangea isn’t blooming, it may be that it needs more morning sun. Too much sun may burn white ones. The plants need plenty of water, still they are drought tolerant and not terribly fussy about soil, preferring a medium, well-drained soil.
If cutting blossoms, cut mature blossoms in the morning when they are holding as much water as possible. Put a little alum on the stem cut to help them last longer in arrangements.
In late winter, treat with dormant oil or dormant spray to suffocate the spores of fungus and the pupa of insects. The plants are heavy feeders. Put chicken manure, if you have it, or organic fertilizer around them in Jan/Feb before they wake up. Mulch in the spring. Use an organic fertilizer in July. Feeding at the right time helps next year’s buds develop. If you need to move a plant that is not blooming, do so in late October/early November while dormant and add a little fertilizer to the hole.
By the beginning of fall the flowers have taken on a tan color and will dry on the stem with their shape mostly intact. The leaves turn to shades of buttery yellow. Leaving flowerheads on the stem can give the garden interest clear into winter. If you have oak leaf hydrangea, particularly well-known for their cold hardiness, fall turns the leaves to lovely dark orange and deep red shades. The blossoms covered with frost or snow can be a garden highlight. Hydrangea blossoms of some varieties grow on new wood, others on old wood. Do not prune heavily until late winter or early spring if you want to encourage vigorous growth. Proper pruning is important for blooms the following year. Make sure you prune according to the needs of the cultivar.
If you grow pink or blue hydrangea varieties (determined by soil acidity) picking some blossoms which still hold a bit of color just prior to the first frost may preserve some color in the bloom. Even if the blooms of white hydrangea have completely faded, a wreath of natural-colored, stem-dried hydrangea can be a welcome fall decoration. If you prefer a brighter color, try using a floral spray in a fall color on the blossoms. A clear floral spray may help preserve blooms from breakage and shedding.
If you have been drying blossoms throughout the growing season, making a fall arrangement or wreath can be beautiful home decor. Tan hydrangea, dried red and yellow roses, yellow yarrow, red-tinged sedum, brightly colored strawflowers, and bits of blue statice in a wreath, door swag, or fireplace basket can show off your gardening skills through the Thanksgiving holiday.