As host of an organic-gardening radio show in Pittsburgh, Pa., for the past 10 years, the No. 1 listener question each and every year is, “Why don’t my hydrangeas bloom?” I’m guessing my listeners aren’t the only gardeners who ponder their hydrangeas’ blooming habits, I thought I’d address it here.
In our area, many folks grow the mop-headed or big-leaved hydrangea (Hydrangea macrophylla), and this particular species is notoriously fussy. Yes, their gigantic pink or blue flowers are gorgeous, but they don’t always perform as we’d like them to. Some years they bloom fantastically, while other years there’s nary a bloom in sight. Because the flower buds of H. macrophylla are formed on the previous year’s growth, they often freeze out over the winter, or folks accidentally prune the buds off when removing those “ugly dead sticks” before they have a chance to sprout.
There’s never a guarantee with H. macrophylla. It’s hardy down to USDA zone 6, but the past few winters have dipped down to 20 below zero here in Pennsylvania. However, some of the newer cultivars are hardy to zone 4 and have been bred to bloom on both old and new wood to increase your chances of success—good news for hydrangea-lovers for sure, but still not a guarantee in my part of the country.
If you want guaranteed blooms from your hydrangea and you live north of zone 6, it’s best to turn to a few other spectacular species of this plant. These selections are far less fussy than H. macrophylla and require very little in terms of pruning and maintenance. I grow all of them at my house and enjoy beautiful blooms each and every season without fail.
Oakleaf Hydrangea (Hydrangea quercifolia)
This is my hands-down favorite hydrangea. It’s a North American native that has oak-leaf-like foliage that turns a brilliant crimson in the fall. It’s peeling, papery bark is an eye-catching winter bonus. At maturity, it can reach up to 8 feet tall, though there are some cultivars with far shorter stature. The creamy white cones of flowers turn pink as the season progresses. It can handle full sun to part shade.
Panicle Hydrangea Hydrangea paniculata)
In mid-summer you’ll see beautiful, large panicles of flowers on this hydrangea species. The straight type bears white flowers, but there are cultivars in various shades of pink and green, as well. It’s a non-native species that is hardy down to zone 3 and can handle full sun to part shade. I love that this hydrangea can be grown as a shrub or as a small tree with the proper pruning. Reaching up to 15 feet tall, it blooms on new wood so there’s no need to worry about the buds freezing out. Grandiflora is my personal favorite variety.
Smooth Hydrangea (Hydrangea arborescens)
This is a fool-proof bloomer if there ever was one! It’s a North American native that is hardy down to zone 4, and it prefers full to partial shade. The flowers of H. arborescens are snowball shaped and can be quite large, depending on the cultivar. My favorite is Annabelle (pictured here), though some newer pink varieties are starting to steal Annabelle’s thunder, including the simply gorgeous Invincibelle Spirit.
Find more of Jessica’s garden suggestions on HobbyFarms.com:
- 6 Flowering Ground Covers For Difficult Spaces
- 7 Carrots I’m Growing This Year
- 5 Plants For Your Pollinator Garden