Hydrangeas are some of the most beloved garden shrubs, but are also among the least understood. Does the Hydrangea bloom on new growth or old growth? Should you prune it in the spring, summer, or fall? Why is it pink when it is supposed to be blue?
Before we can answer the questions about pruning and color, it helps to understand a bit about the types of Hydrangeas you can buy.
Many Hydrangea shrubs set flower buds in the fall for a bloom the next spring. This means that the flowers have to live through cold weather, not be pruned at the wrong time, and survive spring temperature swings.
The Hardy Hydrangea group is newer but much beloved because these shrubs form flowering buds at the beginning of the summer. It is almost impossible not to enjoy a gorgeous bloom from these shrubs each year.
These shrubs grow well in full sun to partial shade in zones 3-9 and have flower clusters in shades of pink and white. The popular Limelight Hydrangea is part of this group.
Lacecap Hydrangeas are so named because of their flowers. Typical Hydrangea flowers with large petals or bracts form a ring around smaller lacy flowers to create a unique and beautiful bloom. These plants bloom on old wood, so do not prune after August.
Plants can be leggy when you purchase them, so spend some time pinching back the shrubs to achieve a full, branching growth habit.
Lacecap Hydrangeas grow best in gardens in zones 5-9. They are susceptible to cold weather, so take care to plant in a protected spot. Most Lacecaps reach heights of 2-4 feet and flower in shades of pink and white.
Everyone loves Mophead Hydrangeas. In fact, when you picture a Hydrangea flower, you're probably picturing a Mophead. They have the large, pom-pom sized flowers in shades of white, pink, blue, or purple. They're popular as part of bridal bouquets and wedding flowers.
The flower color of many of these plants is dependent on the pH of the soil where they live. Alkaline or neutral soils will produce pink blooms and acidic soils will produce blue blooms.
Mophead Hydrangeas grow well in zones 5 – 9 and will produce well in sun to partial shade. They need moist soil and bloom in mid summer through late fall.
Mountain Hydrangeas give lots of flowers from a little package. These small wonders are 2-3 feet in height and spread with lacy purplish-white blooms. Gardeners with limited space love these petite powerhouse bloomers. The small shrubs are covered in flowers from summer through fall.
Currently we offer two varieties for sale. They both grow well in full sun to partial shade. They rebloom throughout the summer, including on new growth so you can't possibly cut off all of the flowers.
Perfect for landscape beds and containers!
Oakleaf Hydrangeas are native summer-blooming shrubs that truly stand out in the landscape.
Unlike other Hydrangeas, Oakleaf Hydrangeas need drier soil in order to thrive. Do you have a woodland garden? It isn't complete without at least one Oakleaf Hydrangea.
Oakleaf Hydrangeas are hardy in zones 5 – 9 with average to dry soil. The average height at maturity is 5 – 6 feet while some varieties can get as tall as 10 feet.
Don't miss the new "Gatsby's" series Oakleaf Hydrangeas. Gatsby's Star™ Oakleaf Hydrangea has truly stunning star-shaped flowers.
Hardy in zones 3-9. Prune after flowering or in the early spring if you need to control size.
How about Flower Color?
A big mystery of Hydrangeas is flower color. How do you get blue flowers if you live in the west or pink flowers in the east? Some hydrangea varieties' flowers are not affected by soil pH, but others are. Read the description of the plant you're buying to see if the one you want is affected by pH. Soil pH affects the amount of aluminum the plants can take up and that affects the color. More aluminum = more of a blue color. Aluminum is more available to plants at a pH of 5.2-5.5. You can lower the soil pH by adding Aluminum Sulfate. You can raise the pH by adding garden lime.
White hydrangea flowers will not turn colors. Only pink or blue flowers can be changed. (And then, only some of those flowers can be changed.)