Hydrangeas are popular, beautiful, and easy plants to grow for summer and autumn. They’re also long-flowering and not bothered by many pests or diseases. The large showy flowers persist for months and with such a range of plant and flower shapes and sizes, there is a hydrangea for every garden. But for the healthiest plants and best possible flower show they must be spaced properly. In this article you’ll learn how far apart to plant hydrangeas types and get tips on doing it right. 

Why you need to know how far apart to plant hydrangeas

The biggest mistake gardeners make when planting hydrangeas is planting them too close together. Overcrowding plants is asking for trouble. Here are four reasons why spacing hydrangeas properly is important:

1. Competition for resources – Planting hydrangeas too tightly means they’ll compete for resources like light, water, and nutrients. 
2. Structural damage – Structural damage is common when shrubs are planted too near a home, shed, fence, or other types of buildings. This also applies when hydrangeas are sited too close to other trees and shrubs.
3. Increased disease risk – It’s more difficult for air to flow through cramped plants and poor air circulation increases the risk of fungal diseases. 
4. Unsuccessful hedge – Hydrangeas make fantastic hedging plants, but if you space them too far apart, your hedge may never grow together into a solid wall of plants. 

How far apart to plant hydrangeas

Spacing depends on several factors including the type of hydrangea, the mature width of the variety, and whether you are planting a hedge or want a specimen plant. Plant a specimen hydrangea alone or in odd-numbered groups in a garden. Growing them this way lets them grow to full size and displays their attractive forms and flowers. Hedges are ideal if you wish to mark a boundary, create a privacy screen, or divide a space. When reading spacing recommendations for hedging, assume that is based on the distance between the center of each plant.

With such an incredible range of hydrangea plant sizes, the first step to knowing how far apart to plant hydrangeas begins by deciding which type and variety to grow. Some grow just 2 feet tall and wide at maturity while others can reach heights and widths of 12 to 20 feet. Start by reading the plant tag. The information listed here includes the mature size of the variety, which you can use as a guideline for spacing. Plant a specimen hydrangea so that when it’s full grown the branches don’t touch other plants. 

How the type of hydrangea impacts spacing

There are five main types of tree or shrub hydrangeas; bigleaf, smooth, panicle, mountain, and oakleaf. And within each type there are varieties that grow to different heights and widths. Let’s look a little closer at hydrangea species and how far apart to plant them.

How far apart to plant bigleaf hydrangeas

Bigleaf hydrangeas are bushy shrubs that typically grow 3 to 4 feet tall and 4 to 5 feet wide, depending on the cultivar and your gardening zone. Bigleaf blooms are rounded or flat with a flower color range that offers blue, purple, mauve, soft pink, and fuchsia pink. Because there is such a wide range of plant sizes, read the cultivar tag to find the ideal spacing. 

• Specimen plant – Nikko Blue is a classic bigleaf hydrangea with blue to pink rounded flowers. Bloom color depends on the soil pH with acidic soils producing blue flowers and basic soils producing pink flowers. Nikko Blue plants grow 4 to 6 feet tall and wide and should be planted about 6 feet apart in shrub, island, or foundation beds. Let’s Dance series hydrangeas grow 2 to 4 feet tall and wide. Leave 4 to 5 feet between specimen plants. Many gardeners choose Endless Summer hydrangeas as they flower very reliably, producing buds on both old wood and new wood. They grow 3 to 5 feet tall and wide so space individual plants 5 to 6 feet from neighboring shrubs.
• Hedge – To create a stunning hedge, plant Nikko Blue shrubs every 4 feet. Let’s Dance series hydrangeas are a bit smaller and need a closer spacing to establish a dense hedge. Plant 2 to 3 feet apart, but do read the plant label for specific recommendations first. A hedge of Endless Summer bigleaf hydrangeas is a spectacular sight and for best results site them 3 to 4 feet apart. 

How far apart to plant smooth hydrangeas

Also known as Annabelle hydrangea, this popular garden plant grows 4 to 5 feet tall and wide with large, rounded white flowers. There are various cultivars available from garden centres in a range of sizes.

• Specimen plant – Space each Annabelle hydrangea plant 6 feet apart and for other smooth hydrangeas, read the plant tags to learn the best spacing. For example, Invincible Spirit II, a pink-flowering cultivar grows 3 1/2 to 4 feet tall and wide. Ultra compact smooth hydrangeas, like Invincibelle Wee White that only grows about 2 feet tall and wide, are planted 3 feet from other plants.
• Hedge – Plant Annabelle 3 to 4 feet apart to create a dense hedge. Invincible Spirit II should also be planted 3 feet apart, but pint-sized Invincibelle Wee White needs to be spaced just 18 to 24 inches for a low hedge.

How far apart to plant panicle hydrangeas

It’s hard to pick a favorite type of hydrangea, but panicle, also called peegee, hydrangeas is near the top of my list. These stunning plants are grown as shrubs or small trees and produce sizeable cone-shaped blooms that persist from mid summer through autumn. The flowers are typically white aging to pink, but there are other color options too depending on the cultivar. The larger panicle hydrangeas grow around 20 feet tall and 15 feet wide. 

• Specimen plant – With such a wide variation in mature plant size you’ll need to follow the recommendations on the plant tag. Generally, large growing cultivars need at least a 10 to 15 foot spacing when planted as specimen shrubs or trees. Or plant a mini variety like Tiny Quick Fire which grows just 2 feet by 2 feet. Plant these 3 to 4 feet apart for specimen plants.
• Hedge – Limelight is a panicle hydrangea that makes a show-stopping hedge! The 12 inch flower heads are green eventually fading to cream and pink. This cultivar grows 6 to 8 feet tall and wide and the correct spacing for a hedge of Limelight is 4 to 5 feet. Plant miniature cultivars like the abovementioned Tiny Quick Fire 18 inches apart for a compact hedge. 

How far apart to plant mountain hydrangeas

Hardy mountain hydrangeas are underrated garden plants with gently mounding forms and pretty lacecap flowers in blues, pinks, and whites. Mature plant sizes varies, with some cultivars growing just 18 inches tall and others up to 5 feet. As always read cultivar descriptions carefully before you buy. 

• Specimen plant – Tiny Tuff Stuff is extremely compact, perfect for perennial gardens or shrub borders. Each plant grows 2 feet tall and wide and needs a 3 to 4 foot spacing. Bluebird is a bit larger, growing up to 5 feet tall and wide. Give it a more room and space each plant 6 feet apart. 
• Hedge – A pint-sized hedge of Tiny Tuff Stuff makes a lovely garden edging or low border. Plant each hydrangea just 18 inches to 2 feet apart, but site larger mountain hydrangeas, like Bluebird, 4 feet apart. 

How far apart to plant oakleaf hydrangeas

Oakleaf hydrangeas are striking plants that are reliable, have showy foliage (that turns deep red in autumn!), and massive cone-shaped blooms. They grow 4 to 8 feet tall and wide and as summer stretches into autumn the white flowers begin to blush pink. Because the mature plant width is cultivar dependant, you must read the description before you plant.

• Specimen plant – Snowflake is a well-known oakleaf hydrangea that grows 5 to 7 feet tall and wide so space them 8 to 10 feet apart. In smaller spaces try Ruby Slippers or Munchkin which grow just 3 to 5 feet tall and wide. Plant them 5 to 6 feet apart in island beds or shrub borders. 
• Hedge – An oakleaf hydrangea hedge is truly show-stopping and you can choose a compost or taller-growing cultivar. Read them mature width of the plant to space them appropriately. Plant Snowflake shrubs 4 to 5 feet apart. If using Ruby Slippers and Munchkin for a hedge, plant 3 to 4 feet apart. 

The best time to plant hydrangeas

Hydrangeas are ideally planted in early spring or early fall when temperatures are mild and there is increased moisture to help promote good root establishment. Certain hydrangea species do best in full sun while others can take partial shade to deeper shade. Be sure to pick a hydrangea type that will thrive in the growing conditions of your yard. Also consider soil with fertile, well-drained soil best for the plants. If I’m planting in the spring I add a slow-release organic flower fertilizer to provide nutrients and give the plants a boost. However, I don’t fertilize if I’m planting in autumn as I don’t want to encourage late growth from the plants. Any tender new growth could be damaged when the temperatures turn cold. Instead, I’ll fertilize the following spring. After planting, mulch the soil with bark mulch to retain moisture and reduce weeds.

More tips on planting a hydrangea hedge

The goal of a hedge is to create a solid wall and, depending on your goals, a hedge may be more loose and natural or tight and formal. The mounding shape of hydrangeas lends itself to natural looking hedges. In this case you’ll want to space the plants far enough apart that the branches and leaves are just touching when they’ve reached their full size. For a more dense hedge, plant the shrubs closer so the branches overlap. Pruning hydrangeas occasionally and at the proper time results in a more formal hedge shape.

Now that we know how far apart to plant hydrangeas, you’ll find in-depth information on growing and caring for them here:

• Hydrangea fall care
• Growing Little Lime hydrangeas: A guide
• 3 beautiful panicle hydrangeas to plant in your garden