So, you want to get to know this incredible family of flowering shrubs? Welcome! We’ve got the guide for you.

Notes about this guide: This guide is intended for our main customer base, who are located outside Philadelphia, PA in growing zone 7A. Ideal growing conditions vary depending on what growing zone you live in and the particular soil and climate conditions of your area. We cover the five species of hydrangea that we carry here at Colonial Gardens.

One Genus, Many Species

A few things hydrangeas have in common:

• All of them are deciduous in our area, losing their leaves in the fall and winter.
• None of them are considered deer-resistant.
• All of them can benefit from yearly fertilization.
• Their “flowers” are actually clusters of flowers and leaves called “inflorescences.”
• They are late to leaf-out! Don’t worry if you don’t see buds right away in the spring. It’s normal for them to look like bare sticks until late April.

While they all belong to one genus of plants, there are some key differences between the different species. Each species has different bloom shapes and colors, tolerances, and pruning times. If you have a hydrangea at your home, you can use this guide to help you identify it so that you can provide it with the best care.

We carry dozens of varieties of hydrangeas. Want to know what varieties we’re planning on carrying this year? Check out our full tree and shrub list here.

Big-Leaf Hydrangeas

Big-leaf Hydrangeas (H. macrophylla) are probably what springs to mind when you think about hydrangeas. If you’re imaging shrubs with deep green foliage and huge, colorful blooms–you are thinking of a big-leaf hydrangea. These plants put out super-sized blooms, bringing punches of color to your summer shade garden.

Popular Varieties: Endless Summer, Pop Star, Eclipse

Photographed: Loveable big-leaf hydrangea. Picture courtesy of Proven Winners.

Flower Shape: Big-leaf hydrangeas can either have a mop-head shop bloom or a lace-cap bloom. The mop-head is the large classic ball whereas the lace-cap is a flat, open shape with larger flowers encircling smaller flowers.

Color: Big-leaf hydrangeas range between a deep red into pinks and purples, all the way to a deep blue. Their intensity can vary depending on variety, but their color is depending upon soil pH. Basic soil will result in a pink bloom. Acidic soil will give you blue blooms, as the plant has the ability to take up more aluminum. Whatever color you pick at the nursery will eventually revert to your soil acidity. If you want to influence the color of your hydrangeas, choose a product like Soil Acidifier for blue or Lime from Espoma for pink. Add in early spring or late winter and reapply as recommended.

How to Grow: Big-leaf hydrangeas reward you with incomparable blooms when they’re happy. That being said, they have a reputation for being tricky to grow. Blooms can be knocked off by cold winter weather. The plant can also underperform in too shady or too sunny conditions. The best way to have success is to plant big-leaf hydrangeas in places with morning sun and afternoon shade. Put down a layer of 2-3” of mulch to help maintain soil moisture and protect the roots from extreme temperatures. Supplement water when necessary.

Pruning: Big-leaf hydrangeas generally bloom off of old wood, which means that the buds for next year are already formed by the winter. Prune them after they flower, before the fall, to maintain shape without compromising next year’s blooms. Some reblooming varieties, like Endless Summer, will bloom off new wood and old wood.

Panicle Hydrangeas:

Panicle hydrangeas (H. paniculata) are the rockstar of the hydrangea world. They are the best choice for full sun and are the most heat and cold tolerant of all hydrangeas. With their exceptional versatility in this family, we use panicle hydrangeas in many of our professional landscape designs as these plants provide reliable flowering with a long-lived bloom for multi-season interest.

Panicle hydrangeas bloom over the summer, but the timing varies depending on the variety. You can find them as small as 3 ft. x 3 ft. or as large as 9 ft.

Popular Varieties: Limelight, Bobo, Firelight

Pictured: Limelight, Limelight Prime, Firelight varieties. Photos courtesy of Proven Winners.

Flower Shape: Panicle hydrangeas are named after their cone-shaped clusters of flowers. While some varieties like Puffer-Fish have more of a mop-shaped bloom cluster, most of them stick to the classic cone shape.

Color: Most panicle hydrangeas begin their blooms in a white or cream. Their flowers are not influenced by soil pH. Instead, they change color as they age. The creamy flowers will change into pinks, mauves, and ruby reds. Limelight hydrangeas are known for the green flowers, which will also age to reds.

How to Grow: Panicle hydrangeas will tolerate full sun to part shade. Some varieties, like Limelight, are known for their great performance in full sun.

When to Prune: Panicle hydrangeas bloom on new wood. That means that you can prune them anywhere from the fall into the early spring, before the new growth starts. We normally wait until early spring to enjoy the dried flower blooms through the winter. Pruning your panicle hydrangea can help encourage a compact growing habit and more flowers.

Smooth Hydrangeas:

Smooth hydrangeas (H. arborens) native hydrangeas here in Pennsylvania, but the ones you’ll find here at the garden center will be much more showy than their wild counterparts. Because they are native, smooth hydrangeas tend to be more reliable performers than their big-leaf counterparts. They are also a host plant for the Hydrangea Sphinx Moth.

Popular Varieties: Incrediball, Annabelle

Pictured: Invincibelle and Incrediball. Photos courtesy of Proven Winners.

Flower Shape: These hydrangeas have the “mop-head” shape, round clusters of flowers. The individual “flowers” and clusters tend to be smaller than big-leaf hydrangeas, but newer varieties like the Incrediball from Proven Winners feature much larger blooms.

Color: Most smooth hydrangeas are white, however, Proven Winners and other breeders have introduced pink varieties as well. The clusters of blooms will change color as they age. The color of the blooms is not influenced by soil pH.

How to Grow: Like many other species, smooth hydrangeas are probably best grown with morning sun and afternoon shade. Too much shade will lead to a leggy plant that flowers less than what you want so aim for 4-6 hours for strong performance. Patience can be key with this variety; while it blooms reliably, it will perform best after a few years in the ground.

When to Prune: Prune anytime between later fall and early spring. While you can prune this hydrangea straight to the ground, leaving about a third of the plant standing should be sufficient for a flush of new growth.

Oakleaf Hydrangeas:

Oakleaf hydrangeas (H. quercifolia) are another native hydrangea to the US! Aren’t we lucky to have such a wonderful array of beautiful plants that occur naturally here on the East Coast? Oakleaf hydrangeas have leaves that resemble oak leaves, which gives them an interesting texture. In the fall, these hydrangeas have a deep burgundy foliage color.

Pictured: Gatsby Gal. Photo courtesy of Proven Winners.

Flower Shape: Oakleaf hydrangeas have a dramatic, pyramidal panicle flower that is generally longer than panicle hydrangeas.

Color: Oakleaf hydrangeas are naturally white, but newer varieties may offer pink flowers or white flowers that age to pink. The color of the blooms are not impacted by pH.

Growing: Oakleaf hydrangeas need morning sun and afternoon shade in our area (southeastern PA). Morning sun gives the hydrangea enough energy to produce dense foliage and ample flowers while protection from the afternoon sun protects them from burning and drying out. They prefer rich, well-drained soil.

Pruning: Oakleaf hydrangeas bloom on old wood, which means that they have their buds already formed for the next season before winter. The best time to prune them without impacting flowering is directly after they bloom. Oakleaf hydrangeas tend to grow naturally uneven, so you can prune out errant or uneven branches at any time–just expect to lose some flowers if you do this in the fall or spring.

Mountain Hydrangea:

If you have trouble with your big-leaf hydrangeas reliably blooming, you might need a mountain hydrangea (H. serrata). Mountain hydrangeas still have the capability of producing blue, purple, or pink flowers, but coming from colder areas, they have a better cold tolerance.

Pictured: Tuff Stuff hydrangea. Photo courtesy of Proven Winners.

Flower Shape: Mountain Hydrangeas have a “lacecap” flower, which means that it has more of a flat, open flower rather than the classic “snowball.” While these flowers are less of a showstopper from a distance, they add a more delicate, whimsical feel to the garden.

Color: Like the big-leaf hydrangea, the mountain hydrangea has flowers that are influenced by soil acidity and the ability to uptake aluminum.  Basic soil will result in a pink bloom. Acidic soil will give you blue blooms, as the plant has the ability to take up more aluminum. Whatever color you pick at the nursery will eventually revert to your soil acidity. If you want to influence the color of your hydrangeas, choose a product like Soil Acidifier or Lime from Espoma.

How to Grow: These hydrangeas tend to be hardier in the cold than their big-leaf cousins. Like other hydrangeas, they benefit from morning sun and afternoon shade. They prefer a good layer of mulch over their roots to help maintain moisture.

Pruning: Mountain hydrangeas bloom on old and new wood and typically should not be pruned. Dead and diseased stems can be removed at any time. Mature plants may benefit from thinning out stems to help promote airflow through the plant.

Photo: Taken by Casey Schmidt Ahl at Chanticleer Gardens.

Flower Shape: This species produces flat, lacecap flower clusters in the summer.

Color: Climbing hydrangea flowers are white and are not influenced by pH.

How to Grow: Climbing hydrangeas typically grow as a large vine, extending over 30’ in length. You should provide it with a strong support system. In the absence of something to climb, it may grow as a groundcover. This species does best with shade from the hot afternoon sun, but morning sun will help it flower more profusely.

Pruning: Climbing hydrangeas bloom on old wood, so they should only be pruned directly after blooming to prevent cutting off buds for next year’s blooms. If your vine is very large and you want to reduce its size, consider pruning it in stages over a few years.