Hydrangeas are a diverse genus of flowering shrubs that are grown for their evergreen foliage and show-stopping blooms. Their pastel-colored blossoms are highly sought after as wedding flowers. For gardeners growing their own hydrangeas, a knowledge of the different species and when they flower is key.
Summer is typically the season for hydrangeas. In warm climates, they begin flowering in late spring to early or mid-summer. In cooler climates, hydrangeas flower a little later, starting in late summer and flowering through fall. During winter and early spring, hydrangeas are dormant.
Related: Are Hydrangeas Poisonous?
Are Hydrangeas Available All Year?
Hydrangeas are a very popular cut flower. They are brilliant wedding flowers because of their color and size. Because the flowering heads are so large, you do not need to buy as many to fill a space, and they are not as fiddly to work with as smaller flowers.
If you are planning a wedding and want to know whether hydrangeas are a viable option, it is important to know when they flower.
Cut hydrangeas are available in spring, summer, and fall months but not during the winter months. There are many new cultivars that are farmed for cut flowers. Flower farms are therefore able to provide the market with hydrangeas for nearly the whole year.
Nurseries and garden centers usually stock hydrangea shrubs year-round. The best time to buy potted hydrangeas is in spring or the fall. This is when it is best to transplant hydrangeas.
When Do Hydrangeas Flower?
Generally, hydrangeas are summer flowers. Usually, they begin flowering in the middle of spring and continue all the way until the end of fall. However, defining a flowering season for hydrangeas is not so simple.
The time of year that hydrangeas flower depends on the climate, the type of hydrangea, and how they are pruned. So many different species and cultivars of hydrangea exist, and all of them flower at slightly different times.
Climate has a major effect on when hydrangeas flower because the temperature has an effect on how quickly buds develop. In warmer regions, hydrangeas flower earlier in the season. In cooler areas, they flower later in the season.
Pruning hydrangeas is important for their flowering. Because these plants flower on old wood, one has to prune away branches with spent blooms early in the spring or late in fall to make sure that the hydrangea flowers the next season.
That being said, there are newer varieties of hydrangeas that flower on new wood and on old and new wood. You need to follow a pruning regime for the particular type of hydrangea you have.
Why Are My Hydrangeas Not Flowering?
It can be extremely frustrating to grow a hydrangea shrub, waiting in eager anticipation for it to flower, and then just keep waiting. Don’t worry. You are not alone. Hydrangeas can be a little dicey when it comes to flowering.
There are several reasons that a hydrangea plant may put off flowering:
- The flower buds get too cold during the winter months
- They are not getting enough sunlight
- They are over-fertilized
- Incorrect pruning regime
If you have hydrangeas that flower on old wood, it is important to know that the flower buds develop in the fall to flower the following spring. So, there will be buds on these hydrangeas all the way through winter.
Hydrangea buds are super sensitive to cold and frost. Freezing winters or a late spring frost can kill the buds and cancel the entire flowering season! For this reason, it is imperative to insulate your hydrangeas over winter. Wrap them in burlap to keep the buds warm.
While hydrangeas are not fond of too much sun, too little sun is also a problem for them. If hydrangeas do not get at least 3 to 4 hours of sunlight daily, they will struggle to flower. This is why areas of the garden with dappled shade and morning sun are optimal for hydrangeas.
If hydrangeas get too much fertilizer or the wrong type of fertilizer, they will use all the nutrients to put on new growth rather than flower. Fertilizers that are high in nitrogen are not good for hydrangeas. Because nitrogen promotes vegetative growth, it will discourage your hydrangeas from flowering.
Hydrangeas need a fertilizer that is high in phosphorus, which encourages the growth of the roots and flowering shoots. You only need to feed hydrangeas twice annually in early spring and mid-summer.
Pruning hydrangeas incorrectly is a major reason that these plants do not flower. If you prune your hydrangea that flowers on old wood in the fall, you are cutting off all the next year’s buds. Therefore, it is better to prune in early spring.
Different Hydrangeas And When They Flower
Hydrangeas come from a diverse genus with many different species. Because these plants have been cultivated as ornamentals for hundreds of years, there are also a huge number of different varieties and cultivars.
New Wood Vs Old Wood Hydrangeas
Hydrangeas that have been bred to flower on new wood will generally flower later in the season, from about late summer through the fall. Hydrangeas that flower on old wood typically flower early to mid-summer.
Varieties of hydrangea that bloom on new wood include the smooth hydrangea (H. arborescens) and the Pee Gee hydrangea (H. paniculata). The buds on these hydrangeas form in the spring on new shoots. Therefore, they need to be pruned in winter or early in spring before the buds form.
Hydrangeas that bloom on old wood are bigleaf or mophead hydrangeas (H. macrophylla) and oakleaf hydrangeas (H. quercifolia). Buds on these varieties start forming in the fall on old wood. Therefore, it is best to prune these in mid-summer, just as they finish flowering.
Hydrangea anomala subsp. Petiolaris or climbing hydrangeas start blooming in late spring and finish in mid-summer.
Panicle type hydrangeas’ bloom time is from late spring to early summer. However, the flowers remain
Bigleaf Or Mophead Hydrangeas
These varieties of hydrangea start flowering in late spring and finish in mid-summer. Some of the latest cultivars re-bloom and will keep flowering throughout the growing season.