Hydrangeas for Every Garden
Weather conditions this year have been ideal in Georgia, and hydrangeas are blooming with enthusiasm. At Gibbs Gardens, there are more than 1,000 blooms to see, including native and cultivated selections. Reinforcing what we know to be true that “the plants don’t read the books,” hydrangeas are blooming about two weeks ahead of what is considered their normal bloom time.
Bigleaf hydrangeas, Hydrangea macrophylla cultivars, thrive in high shade, with lots of light but protection from hot afternoon sun. Japanese maples and dogwoods provide the ideal canopy for theses hydrangeas. Shrubs like Anise, Illicium species, make good companions along with ferns and shade-loving perennials.
There are both mophead and lacecap varieties of bigleaf hydrangeas, and the flowers can range from blue to pink to lavender. In acid soils (low pH), flowers tend to be blue. Pink flowers occur when the pH is higher, often when the plants are grown near limestone. White flowers don’t change colors.
I have always been charmed by the old fashioned blue mophead hydrangeas and the many different variations. I especially like them in combination with old fashioned orange daylilies, sometimes called ditch lilies (maybe because they grow along roadsides and don’t require any special care).
A handsome Georgia native that is always popular (and with good reason) is the oakleaf hydrangea, Hydrangea quercifolia with oak leaf-shaped leaves. Beginning in June or earlier (depending on the year), large cones of white flowers persist for weeks and then often turn tinges of rose as they age. A real bonus is the cinnamon peeling bark in winter and the colorful autumn foliage in shades of red and burgundy. While oakleaf hydrangea is a predominant species that occurs throughout North Georgia, the cultivar ‘Snowflake,’ a selection with double flowers, was planted in Gibbs Gardens.
Flowers on the oakleaf hydrangea occur on second year growth. You shouldn’t have to worry about pruning, though, unless plants get too large for the area where you have them planted. If space is limited, try one of the dwarf cultivars like ‘Pee Wee’ or ‘Sikes Dwarf.’ Both of them grow more in the range of 2- to 4-feet tall and wide compared to the species that can easily reach 8- to 10-feet tall.
Another native hydrangea with white flowers that occur on current season’s growth is the smooth hydrangea, Hydrangea arborescens, known to many for one of its selections, ‘Annabelle.’ The flowers, anywhere from 4 to 6 inches across and up to 12 inches in diameter, remind me of lace.
Those are just a few of the hydrangeas blooming now. As summer continues, selections of Hydrangea paniculata, like ‘Limelight’ and ‘Tardiva,’ will take center stage. Both of those thrive in full sun and bloom on current season’s growth, so you don’t have to worry about pruning off potential flower buds.
Tips for Growing Hydrangeas
- Grow a variety of types so that you have a long season of bloom.
- Fertilize once or twice in the summer but not after August. Follow directions on the package for amounts, and don’t over fertilize.
- Don’t fertilize sick or unhealthy plants.
- Keep plants watered during dry spells.
- Prune mophead types as soon as they finish blooming, but don’t overdo it.
- Hydrangea paniculata types can be pruned back to about 12 inches tall early in the season (March) before new growth begins. If you prune later, the flowers will be delayed.
- Combine hydrangeas with evergreens and perennials for the best effect.
- Hydrangeas make great container plants. Adjust the watering and fertilizer as needed.