Guide to Growing Bracted Hydrangeas
Though they are far from the best-known type of hydrangea, bracted hydrangeas (H. involucrata) like Blue Bunny are easy to grow and beautiful. Whenever anyone sees this plant in bud or in bloom in our trial garden, they immediately want one, and we're pleased to be able to make that dream a reality! The unusual name "bracted hydrangea" refers to the bracts, or petal-like structures, that surround the cluster of florets that burst forth from the buds. All you really need to know, though, is that this is one special hydrangea that will set your collection apart from the rest.
Hardiness/climate
Native to Japan and Taiwan, bracted hydrangeas likewise like warm, humid, moist conditions. They are hardy to USDA zone 6 (possibly zone 5 with protection), and because they bloom on new wood, winter damage is less of a threat to their flowering than with bigleaf hydrangeas that bloom on old wood.
Size
Bracted hydrangeas tend to have a spreading habit that grows into a wide, handsome clump as they mature. Their height can range from 2-4', with the lower end more common in cold climates and the higher in mild climates.
Light
Filtered light all day is ideal, though it would be safe to say that they can grow in full to part sun, especially if they are mulched and watered regularly.
Soil
Moist, well-drained soil will provide the best-looking foliage and flowers, as it most closely approximates the conditions where bracted hydrangeas grow in the wild. This is a plant that is very at home in woodland gardens where shade helps keep soil moist.
Blue Bunny is the rare hydrangea that keeps its purple-blue color in all soil conditions. However, it is best grown in acidic to only slightly alkaline soils.
Fertilizer
Regular fertilizing isn't necessary, but if you live in the colder end of its range, you may wish to fertilize in early and late spring to help it recover from any winter damage that occurs. We recommend a granular (not liquid) rose fertilizer.
Flower Color
The flowers of Blue Bunny are extremely unusual in that they keep their blue-lavender color regardless of soil chemistry. The white portions also stay white in all conditions as well.
Pruning
Bracted hydrangeas do not need or benefit from yearly pruning as other new wood blooming hydrangeas do. If you find that your plant has a lot of winter damage, you can remove any dead portions once the new growth begins and it's clear where any damage occurred.