All About Hydrangeas!
Hydrangeas are a genus of over 75 species and 600 named cultivars that are native to a wide range of regions and countries, including Japan, Asia, Indonesia, Himalayan mountains, and the Americas. While hydrangeas can grow as a climbing vine and trees, they are most commonly grown as a shrub. The plants can grow from 1 foot tall all the way to close to 100 feet tall as a climbing vine.
The name hydrangea comes from the Greek words “hydor” meaning water and “angos” meaning vessel. Which when put together roughly translates to “water barrel”, referring to the hydrangea’s need for plenty of water and its cup-shaped flower.
The beautiful flowers produced by this plant are what makes the hydrangea so popular. Hydrangeas put on a showy display from early summer all the way into fall. The large flowers come in a variety of shapes, colors, and sizes. Hydrangea blooms can be pink, blue, red, white, purple, and green. These beautiful flowering shrubs can grow in partial shade to full sun depending upon the variety.
Many people remember hydrangea shrubs from their childhood. Today gardeners are falling in love with them all over again. The great news is that we can now grow many hydrangea varieties that our parents and grandparents never even dreamed of. Some newer varieties grow in colder climates, some re-bloom throughout the season, some are so small they will fit into a perennial border, and others have amazingly large blooms and deep colors.
There are several types of hydrangeas, each having their own unique characteristics and growing preferences.
Bigleaf Hydrangea | Hydrangea machrophylla
Bigleaf hydrangeas, also known as Mophead, are the most popular and widely-used type of hydrangea in the landscape. Most varieties have pink or blue flowers, although a few varieties are white. The color of the flowers (other than the white varieties) will be dependent on the soil’s pH. Acidic soils will produce purple/ blue flowers, while alkaline soils will produce pink flowers.
Hardy Hydrangea | Hydrangea paniculate
Panicled or Hardy Hydrangea produces its flowers on ‘new wood’ or the current season’s growth. These hydrangeas should be pruned in late winter or early spring. You can cut these varieties almost back to the ground if you desire, although typically they are pruned down to between 1’-3’ tall. For Hydrangea Tree forms, prune the head of the tree (or canopy) back down to 2’-3’ tall above the single trunk and 2’-3’ wide. Do NOT prune the single trunk.
Smooth Hydrangea | Hydrangea arborescens
Smooth hydrangeas are another type of hydrangea that produces its flowers on ‘new wood’ or the current season’s growth. These varieties should be pruned in late winter or early spring. Prune the plant back to between 1’ and 2’ tall as this will leave a good framework to support the upcoming summer blooms without the plant flopping over under the weight of its abundant flowers.
Oakleaf Hydrangea | Hydrangea quercifolia
The Oakleaf hydrangea is a dramatic blooming shrub with four seasons of interest. It blooms best in areas where summers are somewhat hot, but it is winter hardy farther north than the macrophylla (mophead). Flower blooms typically emerge creamy white and mature to pink as fall approaches. A tremendous advantage of the Oakleaf is that it can thrive in much dryer locations than its cousins. Bigleaf/Mophead varieties can struggle in sandy soil or dry areas, but the Oakleaf hydrangeas thrive with very little attention.
The Oakleaf gets its name from the shape of its beautiful large leaves. These leaves often turn colors of brilliant red, orange, yellow and burgundy in the fall if planted in a sunny location with a little afternoon shade. The Oakleaf hydrangea can tolerate and even thrive in much sunnier areas than the bigleaf types of hydrangeas.
Climbing Hydrangea | Hydrangea petiolaris
Climbing Hydrangeas can grow anywhere from 30 to 80 feet tall. However, you can prune these to shorter heights. The vines require heavy support to grow, and they will climb up trees, buildings, arbors, trellises, pergolas, fences and other taller structures.
These plants typically bloom from early summer until late fall. The flowers are typically white, very fragrant, and similar to the blooms on Bigleaf Hydrangeas.
Climbing hydrangeas can grow well in full sun to partial shade, however they prefer some mid-late afternoon shade. While plants that get more sun typically do bloom more, this is one of the few vines that can tolerate large amounts of shade, although it will not bloom as much in shaded areas.
Hydrangea Standards | Hydrangea paniculata tree
Of all the small, flowering trees available, hydrangea trees are the most dramatic when in full bloom. They are easy to grow in almost all parts of the U.S. (except frost free areas) and they will bloom dependably year after year. Hydrangeas do not naturally grow into the shape of a tree; nurseries prune them into a single trunk when they are very young. The only type of hydrangea that can be made into a tree is Hydrangea Paniculata.
Hydrangea trees can be grown in full sun if they receive adequate moisture. However, they prefer a little shade during the hottest part of the afternoon, especially if the conditions are on the dry side.