Fountain Grass

Pennisetum alopecuroides

Fountain Grass is a perennial ornamental grass that forms a graceful, rounded presence about 3 feet tall and 3 feet wide. Its bottlebrush plumes arrive from late summer into fall, giving borders and larger planting sweeps a softer vertical accent after many earlier perennials have peaked. Use it where its arching outline can be seen from more than one direction rather than pressed into a crowded planting.

Sunlight Full Sun

Water Moderate

USDA zones 5–9

Planning spacing 3 ft

Typical mature size 3 ft tall, 3 ft wide

Typical bloom Late summer - fall

Fountain Grass spacing and mature footprint

Space Fountain Grass 3 ft apart, measured center to center (90 cm).

The mature spread is about 3 ft (90 cm), so neighboring plants just meet at maturity without crowding.

Treat 3 ft as a planning baseline — cultivar and local growing conditions shift the final footprint.

Compare with the full ornamental grass spacing chart

Three plants set 3 ft apart, center to center; shaded circles show the 3 ft mature spread.

Placement and use

Place Fountain Grass in full sun at the middle or back of a border, or repeat it through a mass planting to create a consistent rhythm. Its mounded, arching habit works well beside straighter paths, walls, and clipped forms, where the foliage can soften hard edges without blocking circulation. Keep the clump set back from narrow walkways so mature leaves and plumes do not spill into the route. Deer resistance can make it a useful structural choice in exposed parts of the garden.

Spacing and mature footprint

Allow a 3-foot-wide circle for each mature clump, measured from the center outward, and space plants 3 feet apart center to center. At that interval, adjacent plants can meet visually as they fill out while retaining enough definition for each fountain-shaped mound to read clearly. In a bed beside a path, reserve additional open edge space for the outward-arching foliage and for access when cutting back old growth.

Sun, water, and soil

Give this grass a full-sun position for the strongest flowering display. It suits dry to moist, well-drained soil and has moderate water needs, so avoid treating it as a planting for a constantly saturated pocket. Place it with other plants that can share regular moisture while the clump establishes, then keep the root zone free of persistent standing water.^[1]

Seasonal notes

The plumes emerge from midsummer into fall and the foliage shifts toward yellow or tan as the season closes, extending the clump’s visual role beyond its bloom period. Leave enough room around the base to cut the old foliage down in late winter before new shoots begin. This annual reset is easiest when the plant is reachable from a bed edge or path without stepping through neighboring plants.^[1][2]

Planning caveats

The species can spread by seed and may become weedy in favorable conditions. For repeated plantings near natural areas or in warm-climate gardens, plan for removing seed heads before seed matures, or select a sterile cultivar where that is important. Do not assume all named fountain grass selections behave alike; mature size and flowering timing can vary by cultivar.^[1][2]

Growing facts

Botanical name: Pennisetum alopecuroides
Type: Ornamental Grass
Category: Ornamental Grasses
Lifecycle: perennial
USDA hardiness zones: 5–9
Sunlight: Full Sun
Water: Moderate
Planning spacing: 3 ft
Typical mature size: 3 ft tall, 3 ft wide
Typical bloom season: Late summer - fall

Plan a garden with fountain grass

References

Fountaingrass - Cenchrus alopecuroides — North Carolina Extension Gardener Plant Toolbox
Pennisetum alopecuroides - Plant Finder — Missouri Botanical Garden