Purple Fountain Grass

Name: Purple Fountain Grass
Brand: Outdoor Dream Builders

Pennisetum setaceum Rubrum

Dramatic ornamental grass with burgundy foliage and feathery purple plumes.

Grown as a warm-season accent in Phoenix Zone 9b-10a; it thrives in intense summer heat but foliage burns and dies back below about 25°F, often returning from the crown after mild winters.

AMWUA Notes

Note: Pennisetum setaceum (green form) is considered potentially invasive per ADWR. Use sterile "Rubrum" cultivar only.

Care Guide

💧Watering

Water established clumps every 10-14 days in summer and monthly in cooler months. It tolerates low water but looks fullest with regular deep irrigation during peak heat.

✂️Pruning

Cut back to a few inches above the crown in late winter before new growth begins to remove tattered, frost-damaged foliage. Comb out old blades any time to keep clumps neat.

🌱Fertilizing

Apply a light application of balanced fertilizer in spring as growth resumes; it is not a heavy feeder and needs little else through the season.

🛡️Pests

Largely pest- and disease-free. In overly wet or shaded conditions watch for occasional rust or crown rot from poor drainage.

☀️Seasonal Notes

Foliage colors deepest and plumes appear from summer into fall. Expect winter dieback with frost; shear old growth in late winter and it flushes back with warm weather.

Soil, Feeding & Propagation

🪨Soil

Adaptable to most well-drained soils; performs well in average garden, sandy, or amended desert soils.

💧Drainage

Needs well-drained soil.

🌱Nutrient Needs

Low feeder.

🌰Propagation

The Rubrum cultivar is sterile and does not come true from seed; propagate only by division of established clumps in spring.

📐Spacing

3-4 ft

🌳Roots & Placement

Fibrous, clumping, non-invasive roots; the sterile Rubrum cultivar will not reseed like the invasive species form.

Placement Tips

•Mass in groups of three or five to amplify the movement of the burgundy foliage and plumes in the breeze.
•Plant along borders, in containers, or at a pool edge where afternoon backlighting sets the plumes glowing.
•Give each clump 3-4 feet of space so the fountain-like form arches freely without crowding.
•Pair the dark foliage against light gravel, pale walls, or golden-flowered plants for high contrast.