The Complete Guide To Hydrangeas
In intimate spaces and wide open landscapes alike, hydrangeas make a bold statement with big gorgeous flowers. Use them to create an informal hedge, to accent the perennial garden, as foundation plants, en masse in an island or a single specimen in a container. Hydrangeas are as versatile as they are beautiful.
Top Hydrangea Varieties
Endless Summer is the original reblooming mophead hydrangea with big beautiful blooms in either blue or pink.
Bloomstruck hydrangea features rigid red stems and intense purple-blue or pink blooms throughout the summer.
Nikko Blue hydrangea is the classic, early summer blooming mophead offering large blue or pink blooms for up to six weeks or more.
Vanilla Strawberry hydrangea blooms in full sun from mid to late summer. The creamy white flower panicles turn deep red-pink as they mature.
Limelight tree form hydrangea offers green tinged white blooms in summer; a perfect large container plant or landscape specimen.
Choosing Your Perfect Hydrangea
Hydrangeas vary in sunlight tolerance from species to species, so it is important to select a suitable variety for the conditions in your landscape. Endless Summer, Bloomstruck and Nikko Blue are from the species Hydrangea macrophylla. They prefer sites with bright filtered sunlight or morning sun and afternoon shade. They will tolerate a bit more sun with consistently moist soil, but wilt in extreme heat regardless of soil moisture and so it’s best to err slightly on the side of shade. Vanilla Strawberry and Limelight are sun loving varieties of Hydrangea paniculata. At least six hours of direct sun exposure is critical for paniculatas to grow and flower their best.
How To Plant Hydrangeas
Hydrangeas require moist, well drained soil. Heavy clay or sandy soils should be amended with generous helpings of compost to improve moisture balance. Mixing compost with native soil at a 1:1 ratio, to a depth of ten or twelve inches is helpful. Do not fertilize at planting time. Four to six weeks after planting, apply a granular fertilizer for acid loving shrubs. Be sure to provide a bit of extra water before fertilizing and for a week or so thereafter.
One of the fun aspects of growing mophead hydrangeas is the option to change the bloom color from blue to pink or vice versa. This can be done by raising or lowering the soil pH. To change from blue to pink, spread one cup of garden lime per foot of height over the entire root zone of the hydrangea. To change from pink to blue, maintain a three inch layer of organic mulch and treat with a solution of 1 Tbsp. aluminum sulfate in 1 gallon of water weekly, throughout the growing season. The color of paniculata hydrangeas cannot be manipulated in this way.
Early on, hydrangeas require little to no pruning; with the possible exception of removing dried blooms if desired. Tree formed Limelight hydrangeas may send up occasional sprouts at the base or along the trunk, which should be pinched off whenever they appear.
When hydrangeas become established after a year or so, the time will come to remove old or occasional damaged stems, which may be safely done in late winter. Prior to the emergence of new growth in spring, simply cut individual damaged or undesirable stems all the way to the ground. If the overall size or shape of the plant must be addressed, the best time to prune is immediately after bloom time for mopheads, or late winter for paniculatas.
Hydrangea macrophylla is originally native to China and Japan, where it is known as “mountain hydrangea”. The wild species exhibits a flat “lacecap” bloom type. Hydrangea paniculata is a native of China and Japan as well, where it may grow to fifteen feet in the wild. Locally, hydrangea leaves are fermented and used to brew tea. Two fairly common hydrangeas native to the U.S. include H. quercifolia (oakleaf hydrangea), H. arborescens (smooth hydrangea).