Short answer
There is no single distance that suits every grass, but a useful starting point for most is somewhere between 1 and 3 feet apart. Small grasses can go closer, and large ones need more room. The most reliable method is to use the mature width listed on the plant tag as your guide.
The general rule: use mature width
Grasses are sold small and grow quickly, so judge spacing by the size the plant will reach, not the size it is in the pot. Measure from the center of one plant to the center of the next.
Two common approaches:
- Spacing roughly equal to mature height. Missouri Extension describes this as satisfactory for small groupings. It works well for clumping grasses of moderate height.
- Spacing between half and the full mature width. Closer spacing gives a quicker filled-in look, and wider spacing gives each plant room to show its shape.
Spacing is partly a matter of taste and purpose, so these figures are guidelines, not rules.
Spacing by size
| Size | Examples | Rough spacing (center to center) |
|---|---|---|
| Small | Blue fescue, small sedges, dwarf fountain grass | 12 to 18 inches |
| Medium | Fountain grass, feather reed grass, pink muhly grass | 2 to 3 feet |
| Large | Maiden grass and other large Miscanthus, switchgrass, plume grass | 4 to 6 feet or more |
These ranges are approximate. Cultivars within a species vary, so check the label.
Mass plantings and screens
For a solid carpet or a living screen, plant closer than you would for individual specimens, so that foliage knits together. For a hedge of tall grass such as feather reed grass, which is narrow and upright, you can usually plant more tightly than you could with arching Miscanthus. Closer planting means you will probably need to divide sooner. See dividing and transplanting ornamental grasses.
Specimens and borders
A single feature grass looks best with room all around it. Allow it to reach full width without being crowded by neighbors. In a mixed border, think about the arching habit of some grasses, which will lean over and cover plants beside them (see perennials to plant with ornamental grasses for good neighbors).
Near walls, paths and other plants
Keep tall or wide grasses back from walls, fences, paths and walkways by at least about half their mature width, so they do not lean on structures or block access. If you are planting in a fire-prone area, also follow local guidance about distance from buildings.
What if you planted too close?
Crowded grasses may flop, grow thin in the middle or suffer from poor air movement. If it happens, dividing and moving some of the plants in spring (or early fall for cool-season types) fixes it. You might also have other reasons for flopping, such as shade or over-feeding.
For a step-by-step guide to getting plants into the ground, see how to plant ornamental grasses. For general care, see the ornamental grass care overview.