With immense billowy blossoms, hydrangeas flaunt an old-fashioned charm that is hard to resist. Colors also beguile with clear blues, vibrant pinks, frosty whites, lavender, and rose—sometimes all blooming on the same plant!
The colors of some H. macrophyllaflowers are affected by the relative availability of aluminum ions in the soil. Acidic soils with a pH of less than 5.5 produce blue flowers; soils with a pH greater than 5.5 product pink flowers. White flowers are not affected by pH.
Unrivaled in the shrub world, these elegant ladies are easy to cultivate, tolerate almost any soil, and produce flowers in mid-summer through fall (when little else may be in bloom). Hydrangeas are excellent for a range of garden sites from group plantings to shrub borders to containers.
Most hydrangeas thrive in rich, porous, somewhat moist soils. Add compost to enrich poor soil.
They prefer full sun in the morning, with some afternoon shade; however, many will grow and bloom in partial shade. This is especially true for the bigleaf hydrangeas (see Recommended Varieties below).
Plant in spring or fall.
Dig a hole as deep as the root ball and 2 to 3 times as wide.
Set the plant in the hole and fill it half full with soil. Water. After water is drained, fill the rest of the hole with soil.
Space multiple hydrangeas about 3 to 10 feet apart.
For the first year or two after planting and during any drought, be sure hydrangeas get plenty of water. Leaves will wilt if the soil is too dry.
When growing H. macrophylla varieties in Zones 4 and 5, don't prune unless absolutely necessary, and then do so immediately AFTER blooming. Otherwise, remove only dead stems in the spring.
If you need to prune an older hydrangea, it depends on which variety you have.
The common Bigleaf hydrangea should be pruned AFTER flowers fade (late spring/early summer). If you prune before bloom, you may not have blossoms the following spring.
Oakleaf, panicle, and smooth hydrangeas blossom on the current seasons' wood so they should be pruned BEFORE bloom when plant is dormant, i.e. late winter or early spring.
In the fall, cover plants to a depth of at least 18 inches with bark mulch, leaves, pine needles, or straw. If at all possible, cover the entire plant, tip included, by making cages out of snow fencing or chicken wire, and loosely filling the cages with leaves. (Do not use maple leaves.)
Try drying hydrangea flowers to create a wreath or other decorations around the house:
Harvest the heads when the flowers have matured and developed a papery consistency.
Remove leaves from stems, and hang upside down in a warm, dry, dark, airy room.
When completely dry (usually a couple of weeks), store in a dry location out of direct sunlight.
To enhance flower color, spritz dry flowers with diluted Rit dye.