If you live in the cool Northwest region of the United States, chances are you have spotted one of summertime's most beloved shrubs in your town--giant orbs of blue, pink, white, and lavender stretching skyward from big, leafy branches. Oh, Hydrangea!
he genus "Hydrangea" is represented by over 11 species of varying bloom shapes, but the cultivar most often used in cut flower arrangements are the globose heads of H. macrophylla (affectionately referred to as "mopheads"). This highly decorative, bulbous form was born in the coastal areas of Honshu, Japan, developed extensively in Europe, and was introduced to the United States well over a century ago.
These immense and billowy flower heads are made up of multiple florets which boast long-lasting color. And the varying colors of Hydrangea are fascinating! Yes, different cultivars will give us clear blues, vivid pinks, pure whites, shades of frosty lavender and coral—but their color and intensity can vary depending on the acidity of the soil or water that is used. Aluminum sulfate will reduce the soil's pH, causing a hydrangea to produce blue and lavender blooms, while a higher soil pH will give us vibrant pinks. It is even possible for some cultivars to produce different color blooms on one plant! (Further on in the growing season, hydrangeas' coloration gets even more interesting, giving us the marbled tones of Antiqued Hydrangeas).
Soil pH aside, the most important element to growing long-stemmed, giant blooms is temperature and light. H. macrophylla originated in the temperate maritime climate of coastal Japan, which bodes well for flower farmers in Coastal California. Hydrangeas love a coastal setting, where cool breezes dissipate the heat. Heat and too much sunlight can be a problem for these blooms, as they are sensitive to drooping from heat stress.
Hydrangeas look stunning as focal pieces in wedding bouquets, or as voluminous color in large, upscale arrangements. They're fun and versatile blooms, giving you the creative freedom to build what you like.