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Units

Hydrangea Spacing Calculator

How far apart to plant hydrangeas, and how many fit your bed, row or area.

Units
In the row
3 to 6 ft
ft

Published for Hydrangea: 3 to 6 ft.

Where you plant
Pattern
ft
More optionsEdge margin
Space at the edge

Half a spacing keeps each plant inside the row ends, so neighbours in the next bed are still a full spacing away. Plant on the edge when the plants may spread past it, such as the first and last post of a hedge line.

Hydrangeas for this row length

11plants

0.22 per foot of row.
Top view, 50 × 4.5 ft. Each circle is the space one plant gets.
Plants per sq ft
0.05
Plants per acre
2,151
Plants per hectare
5,315
Ground per plant
20.25sq ft
Ground covered
225sq ft

How these numbers are worked out

In a square pattern the rows are one spacing apart, so each plant takes spacing × spacing of ground.

4.5 ft × 4.5 ft = 20.25 sq ft per plant

43,560 sq ft per acre ÷ 20.25 sq ft = 2,151 plants per acre

Per-area figures ignore the edges. The count for a bed, row or circle places each one, so it is usually a little lower. One acre is 43,560 sq ft; one hectare is 10,000 m².

How far apart to plant hydrangeas

Space hydrangeas by the species. Bigleaf (Hydrangea macrophylla) and smooth hydrangeas (H. arborescens) go 3 to 6 feet apart, since NC State Extension's plant toolbox gives bigleaf a mature size of 3 to 6 ft tall and wide and smooth hydrangea 3 to 5 ft. Panicle (H. paniculata) and oakleaf hydrangeas (H. quercifolia) are larger and need 6 to 12 feet: panicle hydrangeas typically reach 8 to 15 ft, and oakleaf up to 8 ft tall and 6 to 8 ft wide.

The calculator opens at 4.5 ft, the middle of the bigleaf range. Pick the species in the variety menu to switch; panicle and oakleaf start at 9 ft.

How many hydrangeas for a row or hedge

Row lengthBigleaf or smooth, 4.5 ftPanicle or oakleaf, 9 ft
10 ft2 (3 with plants on both ends)1 (2)
25 ft5 (6)2 (3)
50 ft11 (12)5 (6)
100 ft22 (23)11 (12)

The first number keeps half a spacing clear at each end of the row, the calculator's default, so a hydrangea at the end does not grow into a walk or a corner. The number in brackets plants right on both ends; set Space at the edge under More options to "None, plant on the edge" to match it.

For a foundation planting along a house wall, measure the length of the bed and use the same count, keeping the row at least half the spacing out from the wall so the shrubs can reach full width.

Which hydrangea, which spacing

  • Bigleaf: generally 3 to 6 ft, with compact cultivars at 2 to 4 ft, per NC State. For a compact cultivar you can drop to the low end of the range. Clemson Extension notes bigleaf hydrangea prefers morning sun and afternoon shade and does poorly on hot, dry, exposed sites.
  • Smooth: 3 to 5 ft tall and wide, the same spacing as bigleaf.
  • Panicle: typically 8 to 15 ft tall, and NC State notes it works as a border or hedge when planted in groups. Clemson describes the 'Peegee' type as a 10 to 15 ft shrub that can be grown as a 25 ft small tree.
  • Oakleaf: up to 8 ft tall and 6 to 8 ft wide; NC State suggests massing it as an informal hedge.

When a label gives a mature width, use that as the spacing: plants set one mature width apart just touch when grown.

Planting hydrangeas

Clemson says spring or fall is the best time to plant. Dig the hole two to three times as wide as the root ball but no deeper than its height, so the plant sits at the same level it grew in the pot.

Bigleaf flower color follows the soil: Clemson keeps the soil at pH 5.0 to 5.5 for blue flowers and pH 6.0 or higher for pink. Test before you plant a row, since the whole hedge will share one soil.

Related tools

For a longer shrub border or a mixed hedge, the hedge spacing calculator compares hydrangeas with other hedge plants. Mulch the new bed with the mulch calculator. For other flowering shrubs, see azalea spacing.