Hydrangeas are some of the most popular garden plants in the world. With their huge beautiful blooms, it’s easy to see why. Six types of hydrangeas are common in North America. They are categorized and identified by flower shape, leaf size, colour, growth habit and overall growing size.
The growing conditions for hydrangeas, whether they need sun or shade, when to prune them and how hardy they are largely depends on the type of the plant. This article shows how to identify hydrangeas and what the 6 most common types are.
One of the most important things to know about hydrangeas is when and how they bloom. The same is important for when to prune them. Old Wood – Blooming on old wood means that the flowers bloom on last year’s stems. New Wood – Blooming on new wood means that the flower buds form on the new stems that have just grown this year. Since they have a lot of new growth to put out first, they take longer to start blooming.
| 1 | Big Leaf Hydrangea – Hydrangea Macrophylla |
Big leaf hydrangeas are the 4 to 5 foot high and wide plants with large white, blue or pink flowers that are often used as hedges to line driveways and fences, or as foundation plants in the front of a house. They grow best in part shade in moist but well-drained soil, but will tolerate full sun if they are well watered.
Big leaf hydrangeas come in two types of flowers – mopheads (big balls) and lacecaps (flatter with a lacy appearance). Big leaf hydrangeas have large, dark green, pointed leaves on both ends that tend to grow in clusters with two leaves on either side of very little branched stems. Many varieties of Hydrangea macrophylla have flowers that will change colour from blue to pink (and vice versa) depending on your soil pH. Acidic soil will produce blue blooms, while alkaline soil produces pink ones. The mophead variety has clusters of showy florets that form large round balls that can bloom from summer to fall.
The lacecap variety has flatter, more delicate flower heads. The blooms are made up of buds in the center, surrounded by showy open wide florets that last about one month, usually fading faster than their mophead cousins.
Big Leaf Hydrangea Specs
Zones: 5 to 11 – Light: Part to full shade – Bloom Time: Summer to Fall – Height: 4′ to 6′ – Spread: 4′ to 6′ – Colour: White, pink, blue, purple, red – Blooms on: All varieties with the exception of newer generations bloom on old wood.
Common Varieties: Blushing Bride – mophead with white to pink flowers; Nikko Blue – mophead with bright blue flowers; Endless Summer – mophead with blue flowers in acidic soil or pink flowers in alkaline soil; Twist-n-Shout – the very first reblooming lacecap with blue flowers in acidic soil or pink flowers in alkaline soil; Cherry Explosion – cherry red lacecap flowers with burgundy fall colour.
| 2 | Mountain Hydrangea – Hydrangea Serrata |
Mountain Hydrangeas are very similar to the lacecap varieties of big leaf hydrangeas except for their smaller their leaves. They bloom on old wood and due to their bud hardiness they are less likely to be affected by late frosts.
The flowers can change colour from pink to blue and vice versa depending on soil acidity. Because of their compact nature, mountain hydrangeas are great for growing in containers.
Mountain Hydrangea Specs
Zones: 5 to 9 – Light: Partial shade – Bloom Time: Summer – Height: 2′ to 4′ – Spread: 2′ to 4′ – Colour: Pink, red, blue – Blooms on: All varieties with the exception of newer generations bloom on old wood.
Common Varieties: Tuff Stuff – reblooming mountain Hydrangea with pink or blue flowers; Tuff Stuff Red – deep pink and green flowers or purple and blue flowers.
| 3 | Panicle Hydrangea – Hydrangea Paniculata |
Panicle hydrangeas are some of the easiest and hardiest hydrangeas to grow. Besides their leaves that are smaller than most other types, they feature showy, cone shaped flowers which tend to start out as a white or greenish colour and turn to a shade of pink or red.
Panicle hydrangeas can grow up to 12 feet high and wide are also available in a standard or tree form. Panicle hydrangeas once established, are very cold hardy and on the opposite also more drought-tolerant than other hydrangea types.
Panicle Hydrangea Specs
Zones: 3 to 8 – Light: Full sun to part shade – Bloom Time: Summer to Fall – Height: 8′ to 12′ – Spread: 8′ to 12′ – Colour: White, green, pink, red – Blooms on: New wood.
Common Varieties: Limelight – starts green and turns to creamy white and a pinkish tone towards the end of summer; Vanilla Strawberry – starts out white and then turns to a bright pink colour; First Editions Berry White – starts white then turns pink and then red.
| 4 | Smooth Hydrangea – Hydrangea Arborescens |
The smooth hydrangea is is one of the hardiest native species that grows wild across much of Eastern Canada and the United States. Many people refer to it as the Annabelle Hydrangea because it used to be the only garden variety. But due to its popularity, there are a number of other smooth hydrangeas available now that provide more selection in colour and size.
The blooms are similar in shape to the big leaf mopheads but are usually larger, and do not change colour with changes in soil pH. The smoth hydrangea is a loosely and widely branched deciduous shrub that typically grows to 3 to 6 feet high and wide. It can adapt to a variety of soil conditions, but is intolerant of drought.
Smooth Hydrangea Specs
Zones: 3 to 9 – Light: Part shade to sun – Bloom Time: Summer to Fall – Height: 3′ to 5′ – Spread: 3′ to 5′ – Colour: White, pink – Blooms on: New wood.
Common Varieties: Annabelle – the original hydrangea with huge white balls for flowers; Invincibelle Ruby – burgundy red flowers on a compact plant; Incrediball – huge white flowers on sturdy stems; Incrediball Blush – huge pale pink flowers on sturdy stems.
| 5 | Oakleaf Hydrangea – Hydrangea Quercifolia |
Oakleaf Hydrangea is a native species that is found in woodlands throughout the Southeast. The oakleaf hydrangea is noted for producing pyramidal panicles of white flowers in summer on exfoliating branches clad with large, 3 to 7 lobed, oak-like, dark green leaves.
Its white or pink flowers are oblong rather than round balls and they turn to different shades of orange, red and yellow. This upright, broad-rounded, suckering, multi-stemmed, deciduous shrub typically grows 4 to 6 feet high and wide.
Oakleaf Hydrangea Specs
Zones: 5 to 9 – Light: Full sun to part shade – Bloom Time: Summer to Fall – Height: 5′ to 8′ – Spread: 5′ to 8′ – Colour: White, pink – Blooms on: Old wood.
Common Varieties: Gatsby Gal – 5′ shrub with greenish blooms that turn snow white; Ruby Slippers – white blooms that turn pink then red; Alice – native cultivar with foot-long flowers that start white and age to pink.
| 6 | Climbing Hydrangea – Hydrangea Petiolaris |
The climbing hydrangea is a vine with beautiful, lacy white blooms. It is a vigorous, sprawling, deciduous, woody vine that clings and climbs by twining and aerial rootlets along the stems, typically maturing over time to 30 to 40 feet long.
Best grown in rich, fertile, moist but well-drained soils in part shade to full shade. Tolerates full sun only if grown with consistently moist soils. Slow to establish, but quite vigorous thereafter. Propagate by seeds or stem cuttings.
Climbing Hydrangea Specs
Zones: 4 to 9 – Light: Part to full shade – Bloom Time: Spring to Summer – Height: 30′ to 40′ – Spread: 6′ to 8′ – Colour: White – Blooms on: Old wood
| Commonly Asked Questions |
Which hydrangeas grow in full sun ?
Panicle hydrangeas (Hydrangea paniculata) are among the most sun-tolerant hydrangea varieties and can thrive in full sun. They require a minimum of six hours of direct sunlight daily to produce abundant blooms. Smooth hydrangeas (Hydrangea arborescens) can thrive in full sun as well but they need adequate moisture and shade breaks during the midday sun. Oakleaf hydrangeas (Hydrangea quercifolia) can grow well in the sun but they need afternoon shade in hotter and dryer climates.
Which hydrangeas grow in the shade?
Climbing Hydrangea (Hydrangea petiolaris), Big Leaf Hydrangea (Hydrangea macrophylla), Oakleaf Hydrangea (Hydrangea quercifolia), Smooth Hydrangea (Hydrangea aborescens) and Mountain Hydrangea (Hydrangea serrata) will all grow in the shade, but most will bloom best in partial rather than full shade.
What types of hydrangeas bloom on new wood ?
Panicle Hydrangea (Hydrangea paniculata) and Smooth Hydrangea (Hydrangea aborescens) are the two hydrangeas that bloom entirely on new wood. Some other reblooming varieties, such as the ‘Endless Summer’ Big Leaf Hydrangea (Hydrangea macrophylla) and the ‘Tuff Stuff’ Mountain Hydrangea (Hydrangea serrata) cultivars bloom on both old and new wood.
What types of hydrangeas bloom on old wood ?
Climbing Hydrangea (Hydrangea petiolaris), Oakleaf Hydrangea (Hydrangea quercifolia), Mountain Hydrangea (Hydrangea serrata) and Big Leaf Hydrangea (Hydrangea macrophylla) all bloom on old wood and should not be pruned in the fall or spring to prevent cutting off the buds.
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