Hydrangeas are an easily recognizable garden plant with blooms that come in different colors from shades of white to notes of blue and pink, resulting in several hydrangea types.
Based on the size of the blooms, plant growth pattern and shape of leaves, there are well over 20 hydrangea species growing worldwide, but only 6 of these are grown in North America.
Not all are cold hardy or otherwise drought tolerant, but some are adaptable to be grown widely across North America.
There are also a wide selection of cultivars with often subtle differences in leaves and blooms, so don’t get the impression that you’re limited to only 6 choices.
I’m going to cover the characteristics of each hydrangea type that you’ll find in the U.S., so you can quickly identify them and choose the one that works best for your garden.
Bigleaf Hydrangeas (Hydrangea Macrophylla)
As you may have gathered from its name, this hydrangea type features large leaves, and it’s also known as the French hydrangea or hortensia.
Another name for the Bigleaf is the ‘mophead hydrangea’ because of its unmistakably large blooms.
At maturity, the plant reaches around 6-10 feet in height and about the same in spread. Bloom time is usually between June and October.
As for their color, blooms are pink, blue, white, lavender, and even red. Flower color can be influenced by the composition of the soil, so you can actually change the color of the blooms by altering the acidity levels of the soil.
As for sun exposure, the bigleaf hydrangea enjoys part shade to full sun. When exposed to full sun, you must make sure that the soil gets adequate moisture if you don’t want the leaves to wilt.
In spring, it’s recommended to tidy the plant up a bit by removing dead wood. Be careful not to snip off buds as they’ll carry the season’s flowers.
There are several selections or strains of Bigleaf hydrangeas. Most notable ones include the Nikko Blue, Endless Summer, Pistachio and Tokyo delight.
Climbing Hydrangeas (Hydrangea Petiolaris)
If you’re looking for a variety that you can climb up a wall or you want to use it to cover an ugly fence or structure, the climbing hydrangea ‘Miranda’ can serve you well on this front.
Climbing hydrangeas can be left to grow even on the ground, but do best if they have a support to climb such as walls, trees or fences. You can have these climb up on the side of your house instead of wisterias or ivy plants.
Climbing hydrangeas grow 30-40 feet tall and 5-6 feet in spread when they have upright support. Left to grow on the ground, climbing hydrangeas can cover an impressive 200 square feet.
This hydrangea variety produces white blooms from May to July. Blooms are fragrant and grow along layered branches.
After the blooming season, it’s recommended to lightly prune the plant to tidy it up and bring it to a manageable size. If you’re pruning to rejuvenate an otherwise damaged hydrangea, make sure you do so in late winter or early spring.
Be careful where you plant this hydrangea as it doesn’t enjoy full sun. It needs part to full shade and thrives in zones 4-8, except zone 7.
Mountain Hydrangeas (Hydrangea Serrata)
Native to Japan, this hydrangea type is less common compared to other varieties in this list, but it can be grown in the U.S. as well.
Selections of this variety that you can find include Tuff Stuff, Blue Billor and Blue Bird.
If you don’t have the space or simply don’t want a large hydrangea variety, Mountain hydrangeas are a dwarf variety that reach only 2-4 feet in spread and height.
Their flowers, however, are also much smaller than the blooms of other varieties, but they still manage to impress. The smaller florets in the center are surrounded by much larger florets, creating an interesting mix. Blooms are similar to those of lacecap hydrangeas.
Blooms are pink or blue and they come in from June to August. You can actually influence the color of the blooms by changing the acidity of the soil. Alkaline soil will result in lilac to pink blooms, while acidic soil will create blue colored blooms.
After flowering, you can prune the plant as needed, bearing in mind that the plant blooms on old wood.
Mountain hydrangeas enjoy part shade, so avoid full sun or full shade when planting. Because of their manageable size, you can grow these hydrangeas in pots and planters.
Oak Leaf Hydrangeas (Hydrangea Quercifolia)
Both the leaves and the blooms of the oak leaf hydrangea are a noticeable departure from the other hydrangea varieties. You may have an easier time identifying this hydrangea by its leaves than by its blooms.
As its name so eloquently suggests, the leaves of the oak leaf hydrangea are shaped like that of the oak tree. In the fall, leaves change colors to a wide palette that includes hues of yellow, orange, burgundy, red and purple, creating an interesting display of autumn colors.
Blooms are also an interesting twist — flowers look like they’re drooping stacked stars. The colors of the blooms are white, purple and pink, and they embellish the interesting foliage from July to September. Blooms are produced by old wood.
For best results, plant in a location with full sun or part shade. They’re drought-resistant compared to other hydrangeas and also tough and cold-hardy.
Notable selections include Snowflake, Pee Wee and Ruby Slippers.
The plant can reach a height of 6-8 feet and the same in spread. It thrives in zones 5-9. Pruning should be scheduled to early spring if you’re looking to remove winter-damaged stems. Otherwise prune after the flowering season.
Panicle Hydrangeas (Hydrangea Paniculata)
Of all the hydrangea varieties on this list, the panicle is the cold hardiest. They’re also the most adaptable and easiest to grow. It grows in zones 3-8, so theoretically they can be grown almost anywhere in North America.
Panicle hydrangea grows large, averaging heights of around 8-15 feet and 6-12 feet in spread. This variety does best when planted in full sun to part shade. It has a much better tolerance to full sun than other hydrangeas.
Its most recognizable feature is the cone-shaped blooms that start out white and turn green as the blooms mature. It blooms on new growth. Pruning in early spring or late winter promotes larger flower clusters.
This hydrangea isn’t finicky about soil. It grows in about any soil, even clay, as long as it’s well draining. In the first two years of its growth, it requires regular watering. Once it’s established, it can withstand a bit of negligence.
As for cultivars, there are quite a few worth mentioning: Little Quick Fire, Limelight, Grandiflora, Pinky Winky, Bobo, and Vanilla Strawberry.
Smooth Hydrangeas (Hydrangea Arborescens)
When in bloom, these hydrangeas are a sight to behold. The large blooms almost cover all the foliage of the plant, making the bloom to foliage ratio bend towards the blooms.
They are a medium-sized hydrangea type that grows in zones 3-9. Considering its size, it can grow to 3-5 feet by 3-5 feet. It enjoys part shade, but does well in full sun as well if the soil is kept constantly moist.
The bloom time of smooth hydrangeas is between June to September. Bloom colors are white to pink and are carried by new growths. First blooms can appear to have a greenish hue to them.
Because they bloom on new wood, it’s recommended to prune the plant back close to the ground in the fall.
Smooth hydrangeas prefer slightly acidic soil that drains well to avoid root rot issues. They need extra watering in mid-summer, during drought periods, or when planted in full sun. If you notice the leaves getting droopy, it means it needs extra watering.
This hydrangea type does not tolerate drought, so avoid planting in full sun if watering is a problem. It also can’t survive harsh winters, so you may need to set up winter protection for it.
It’s not prone to pest problems or other diseases.
Cultivars to look for include the Annabelle, Incrediball, and Invincibelle Spirit.
These are the most common types of hydrangeas that grow in North America. Some of them are more sensitive to cold so you’ll need to take winter protection measures to ensure their survival during particularly harsh winters. Others can withstand the harsh winter with a thick layer of mulch spread over the roots.
Whether you choose based on their blooms, growth pattern or ease of care, all hydrangeas are all easy to grow once you understand their basic requirements.
Correct watering and adequate sun exposure are crucial to keeping these plants healthy and blooming. Blooms are available in a variety of colors and shapes. Leaves range from small to large, heart-shaped to oak leaf-shaped.
Hydrangeas are easy to keep around, some can be kept even in planters, others do best when planted outside. If space in your garden is an issue, dwarf varieties like the Mountain hydrangea can be a good compromise.