How To Tell What Kind Of Hydrangea I Have

If you have a hydrangea in your garden, you might wonder about its specific type. Knowing how to tell what kind of hydrangea I have is the first step to giving it the right care. This guide will walk you through the simple clues to look for, from flower shape to leaf texture.

Identifying your hydrangea is like solving a fun puzzle. You just need to know which pieces to examine. The most important clues are the flowers, leaves, and overall growth habit. Let’s break it down.

Start With the Flowers: The Biggest Clue

Look closely at the blooms. Their shape, color, and how they are arranged tell you a lot.

Mophead (Bigleaf) Hydrangeas: These have the classic, large, round flower balls. Each bloom is a cluster of many smaller florets. They are often blue, pink, or purple.
Lacecap Hydrangeas: These have a flat, delicate-looking flower head. A center of tiny, bud-like flowers is surrounded by a ring of larger florets. They are a type of Bigleaf hydrangea.
Panicle Hydrangeas: The flowers are cone-shaped or panicle-shaped. They often start white or green and may turn pink or red as they age. The blooms are pointy, not round.
Smooth Hydrangeas: These have large, round, snowball-like flowers that are typically pure white. They bloom on new wood each year.
Oakleaf Hydrangeas: Their flowers are long, cone-shaped panicles, similar to Panicle types, but the plant has very distinct leaves (we’ll get to that). The blooms often fade to beautiful pink and tan shades.
Climbing Hydrangeas: They produce flat, white, lacecap-style flower clusters against a backdrop of aerial roots and clinging vines.

Examine the Leaves

Leaf shape and texture are dead giveaways for some varieties.

Bigleaf Hydrangea Leaves: These are thick, shiny, and broadly oval with a pointed tip and serrated edges. They are a lush, dark green.
Oakleaf Hydrangea Leaves: This is the easiest identifier. The leaves are shaped like oak leaves, with 3-7 deep lobes. In fall, they put on a spectacular show of burgundy and purple.
Panicle & Smooth Hydrangea Leaves: Their leaves are simpler. They are matte (not shiny), oval to lance-shaped, and have a rough texture. They are ususally darker green and feel coarse.
Climbing Hydrangea Leaves: The leaves are heart-shaped or oval with a pointed tip and finely toothed edges. They are a glossy, medium green.

Consider the Plant’s Growth Habit and Size

How your shrub grows can narrow down the options.

Panicle Hydrangeas: Often grow very large, like a small tree. They can be pruned into a tree form (a “standard”).
Climbing Hydrangeas: They are vines that cling to walls, fences, and trees. They are slow to establish but can eventually cover a large area.
Oakleaf Hydrangeas: They have a more open, spreading habit and beautiful, peeling cinnamon-colored bark on mature stems.
Smooth Hydrangeas: Form a rounded, multi-stemmed shrub, typically 3-5 feet tall and wide.
Bigleaf Hydrangeas: Form a dense, rounded mound of foliage and flowers.

The Blooming Time and Wood Type

When does your hydrangea flower? And on what stems?

This is a critical piece of the puzzle for pruning. Hydrangeas bloom on either “old wood” or “new wood.”

Old Wood Bloomers: Flower buds are formed in late summer on the previous year’s growth. If you prune in fall or spring, you might cut off the flowers. Bigleaf (mophead & lacecap), Oakleaf, and Climbing hydrangeas typically bloom on old wood.
New Wood Bloomers: Flower buds form on new growth that emerges in the current season. You can prune these in late winter or early spring without losing blooms. Panicle and Smooth hydrangeas bloom on new wood.

Note: Some newer Bigleaf varieties are “reblooming” and flower on both old and new wood, giving you a longer show.

A Simple Identification Flowchart in Steps

Follow these steps in order.

Look at the flower shape. Is it a round ball (Mophead), a flat disk (Lacecap), or a cone (Panicle/Oakleaf)?
Check the leaves. Are they shaped like oak leaves? If yes, you have an Oakleaf hydrangea. If they are thick and shiny, it’s likely a Bigleaf type.
Note the plant’s form. Is it a vine? It’s a Climbing hydrangea. Is it huge and tree-like? It’s likely a Panicle.
Observe the bloom time and color. Does it bloom very early on old stems? Does its flower color change with soil pH (blue to pink)? That’s a classic Bigleaf trait. White flowers that turn pink are often Panicle types.

Why Soil pH Matters for Color (But Not for ID)

Many people think flower color is a way to identify the type. This is only partly true. Only Bigleaf (Hydrangea macrophylla) varieties can dramatically change color based on soil acidity.

Acidic soil (pH below 6.0): Promotes aluminum availability, leading to blue or purple flowers.
Alkaline soil (pH above 7.0): Locks up aluminum, resulting in pink or red flowers.

White or green-flowered hydrangeas, like most Panicle, Oakleaf, and Smooth types, do not change color based on pH. Their color is fixed. So if you have a pink hydrangea, it could be a Bigleaf or a Panicle. You need to look at the flower shape to be sure.

Common Hydrangea Varieties and Their Traits

Here’s a quick reference for popular cultivars you might own.

Bigleaf Hydrangeas (Hydrangea macrophylla)

‘Nikko Blue’: Classic mophead with vibrant blue flowers in acidic soil.
‘Endless Summer’: A reblooming mophead that flowers on old and new wood.
‘Twist-n-Shout’: A popular reblooming lacecap variety.

Panicle Hydrangeas (Hydrangea paniculata)

‘Limelight’: Famous for its large, lime-green flowers that turn pink in fall.
‘Little Lime’: A dwarf version of ‘Limelight’.
‘Fire Light’: Strong stems with white flowers that turn a deep, rich red.

Oakleaf Hydrangeas (Hydrangea quercifolia)

‘Alice’: Very large cultivar with enormous flower cones.
‘Ruby Slippers’: A compact form with blooms that turn deep ruby red.
‘Snow Queen’: Known for its profuse, upright white flowers.

Smooth Hydrangeas (Hydrangea arborescens)

‘Annabelle’: The classic, with huge, white snowball blooms.
‘Incrediball’: An improved ‘Annabelle’ with stronger stems that hold up the big flowers.

Climbing Hydrangeas (Hydrangea petiolaris)

This species is usually sold by its botanical name. It’s a slow but steady grower that clings with aerial rootlets.

FAQ: Answering Your Hydrangea Questions

Q: My hydrangea has never bloomed. What type is it?
A: This is a common problem, often with Bigleaf hydrangeas. If it has big, glossy leaves but no flowers, it’s likely a Bigleaf that’s buds were damaged by a late frost or improper pruning. Check if it’s planted in too much shade, which can also limit blooms.

Q: Can I change the color of any hydrangea?
A: No. Only Bigleaf (and some Lacecap) hydrangeas can change from pink to blue or vice versa based on soil pH. White hydrangeas stay white.

Q: How do I know if I should prune my hydrangea?
A: First, identify the type using the steps above. If it blooms on new wood (Panicle, Smooth), prune in late winter. If it blooms on old wood (Bigleaf, Oakleaf, Climbing), prune only right after it flowers to avoid cutting off next year’s buds.

Q: What is the most common hydrangea?
A: In many gardens, it’s the Bigleaf mophead hydrangea. However, Panicle hydrangeas like ‘Limelight’ have become extremly popular due to their hardiness and reliable blooming.

Q: My hydrangea looks different than my neighbor’s, but we bought the same name. Why?
A: Soil pH can change flower color. Sun exposure affects plant size and leaf color. Slight genetic differences in propagation and local growing conditions can all make the same variety look a bit different.

Identifying your hydrangea is a rewarding skill. Once you know what you have, you can provide the perfect care for it to thrive. Take a close look at your plant today—the answers are all right there in its flowers, leaves, and shape.