Arizona's Most Dramatic Purple Ornamental Grass — Purple Fountain Grass

Purple Fountain Grass (Pennisetum setaceum 'Rubrum') is Arizona's most popular ornamental grass for adding year-round color and movement to desert landscapes. Its deep burgundy-purple foliage forms an elegant, arching mound that erupts with feathery rose-to-tan plumes from summer through fall — creating one of the most eye-catching spectacles in any Phoenix Valley garden. This heat-tough grass thrives where other plants struggle, performing as a reliable perennial in Phoenix's warm climate. Whether you're adding a bold focal point to a courtyard in Scottsdale, lining a driveway in Chandler, or creating textural contrast in a low-water border in Mesa — Purple Fountain Grass delivers non-stop drama with minimal maintenance.

Purple Fountain Grass Plant Details

Attribute	Detail
Scientific Name	Pennisetum setaceum 'Rubrum'
Common Names	Purple Fountain Grass, Red Fountain Grass, Crimson Fountain Grass
Mature Height	3–5 feet
Mature Width	2–4 feet
Growth Rate	Moderate to Fast — 1–2 feet per year in Phoenix
Sun	Full sun (6+ hrs). Handles reflected heat from walls.
Water	Low once established. Highly drought-tolerant.
USDA Zones	9–11 (Phoenix is Zone 9b–10a)
Soil	Well-draining. Adapts to Arizona caliche soils.
Foliage	Semi-evergreen — deep burgundy-purple color year-round in Phoenix
Bloom Color	Rose-burgundy to tan feathery plumes, summer–fall

Purple Fountain Grass Uses in Phoenix Landscapes

Dramatic Focal Point and Accent Planting

With its bold burgundy color and graceful fountain shape, Purple Fountain Grass is the ultimate specimen plant for Phoenix landscapes. Place one at the end of a driveway in Gilbert, in the center of a desert garden in Glendale, or flanking an entryway in Tempe for an instant statement. It pairs beautifully with silver-toned plants like Desert Spoon or Agave, letting the rich purple color pop against lighter foliage.

Drought-Tolerant Borders and Mass Plantings

Purple Fountain Grass excels in sweeping mass plantings along walls, fences, and property lines where its uniform height and color create a cohesive, low-maintenance border. Plant 2–3 feet apart for a full hedge effect, or 4–5 feet apart for individual clumps with breathing room. In mass plantings, pair it with Texas Sage or Ruellia for seasonal color contrast.

Poolside and Patio Landscaping

Purple Fountain Grass is relatively tidy compared to other ornamental grasses, making it suitable for pool-adjacent planting when positioned a few feet back from the water. Its feathery plumes add elegant movement around pools in Peoria and Scottsdale without creating excessive debris. For best results, place 4–6 feet from pool edges to minimize fall plume shedding.

Container Planting

Purple Fountain Grass thrives in large containers (15+ gallons) on patios and entryways throughout the Phoenix Valley. In pots, it serves as a striking "thriller" plant in combination arrangements with trailing lantana or compact succulents. Move containers to a protected spot during the rare frost events in Phoenix's coldest winter nights.

Best Time to Plant Purple Fountain Grass in Phoenix

Fall (October–November) is the ideal planting window for Purple Fountain Grass in Phoenix. Warm soil temperatures encourage quick root establishment, while cooler air reduces transplant stress — giving plants 6–8 months to develop strong roots before the first Phoenix summer. Spring (February–April) is the next best window. Avoid summer planting if possible; plants will survive but require extra water and attention during establishment in Phoenix's extreme heat.

How to Plant Purple Fountain Grass

1. Dig wide, not deep — Dig a hole 2–3 times the width of the root ball at the same depth. Never plant too deeply.
2. Check for caliche — Break through any caliche hardpan with a breaker bar to ensure proper drainage. Poor drainage is the #1 killer of ornamental grasses in Arizona.
3. Backfill with native soil — Use the original soil; mixing in 20% compost is fine but not required.
4. Spacing — Space 3–4 feet apart for borders; 4–5 feet apart for individual specimens.
5. Water basin — Build a 3–4 inch soil ring around the plant to direct water to the root zone during establishment.
6. Mulch — Apply 2–3 inches of bark or gravel mulch to retain moisture and moderate soil temperature.

Watering Purple Fountain Grass in Phoenix

First Year Watering Schedule

• Weeks 1–2: Every 1–2 days, deep and slow (20–30 minutes per session)
• Months 1–2: Every 3–4 days
• Months 3–6: Every 7–10 days (every 5–7 days during peak summer heat)
• After Year 1: Every 10–14 days in summer; every 3–4 weeks in winter

Drip Irrigation

Place drip emitters 12–18 inches from the base of each plant. Use 1–2 GPH emitters for 1-gallon plants and 2–4 GPH for 3–5-gallon plants. Once established, Purple Fountain Grass in Phoenix needs surprisingly little supplemental water — its deep roots access moisture effectively between irrigation cycles.

How fast does Purple Fountain Grass grow in Phoenix?
In Phoenix's warm climate, Purple Fountain Grass is a fast grower — expect 1–2 feet of new growth per season, reaching its mature 3–5 foot height within 2 growing seasons. Cutting it back to 6–8 inches in late February encourages vigorous new growth each spring.

Is Purple Fountain Grass a perennial or annual in Phoenix?
In Phoenix (Zone 9b–10a), Purple Fountain Grass performs as a reliable perennial. While it's technically tropical and can suffer frost damage in unusually cold winters, Phoenix's mild climate allows it to survive and re-sprout year after year. In rare freeze events, established plants typically recover from the roots.

Can Purple Fountain Grass handle Phoenix's summer heat?
Yes — this is one of Purple Fountain Grass's greatest strengths. Native to hot, arid climates, it actually thrives in Phoenix's 110°F+ summers and produces its most spectacular plume display in late summer and fall when most other plants are looking stressed.

Should I cut back Purple Fountain Grass in Arizona?
Yes — cut established plants back to 6–8 inches in late February or early March before new growth emerges. This annual cutback keeps plants tidy and stimulates the most vigorous new growth each spring. Avoid heavy cutting in fall or winter.

Is Purple Fountain Grass invasive in Arizona?
Standard green Pennisetum setaceum is considered invasive in parts of Arizona. The purple cultivar ('Rubrum') produces fewer viable seeds and is less of a concern, but it's good practice to deadhead spent plumes if planting near desert washes or wildland interfaces.

You May Also Like

Regal Mist Pink Muhly Grass — A native-adapted muhly grass with spectacular soft-pink fall plumes that pairs beautifully with Purple Fountain Grass in mixed borders.

Mexican Thread Grass — A fine-textured, airy ornamental grass offering a lighter contrast to Purple Fountain Grass's bold burgundy color.

White Cloud Muhly Grass — A stunning white-plumed muhly variety that creates a beautiful color contrast when planted alongside Purple Fountain Grass.

Giant Lily Turf — An evergreen groundcover with bold strap-like leaves that layers well with Purple Fountain Grass for textural contrast.

Desert Spoon — A sculptural desert accent whose silver-blue rosettes create a dramatic color contrast with Purple Fountain Grass's deep burgundy foliage.

How Many Purple Fountain Grass Do I Need?

Purple Fountain Grass forms an arching mound 2 to 4 feet wide, so space it for the fountain form rather than a clipped hedge. Use these groupings:

• Single specimen: Plant one as a bold burgundy focal point at a driveway end or entry, leaving 4 to 5 feet of clear space so the plumes can arch.
• Drift or mass: For a cohesive color border, plant in odd-numbered groups of 3, 5, or 7 spaced 3 to 4 feet apart center to center.
• Poolside: Set plants back 4 to 6 feet from the water's edge so fall plume shedding stays off the deck.

Purple Fountain Grass Season-by-Season in Phoenix

• Spring (Feb-Apr): Cut clumps to 6 to 8 inches in late February, then vigorous burgundy blades flush back fast. Best second planting window.
• Summer (May-Sep): Peak performance. It thrives in 110F+ heat and reflected warmth, and the first rose-burgundy plumes rise in late summer.
• Fall (Oct-Nov): Visual peak with the fullest feathery plume display. Prime planting season.
• Winter (Dec-Jan): Holds its purple color through mild Valley winters. It is frost-tender: a hard freeze below about 28F burns the foliage, but established plants resprout from the roots in spring. Cover in frost pockets or move containers to a protected spot on freeze nights.

At a Glance

✔ Heat-Loving (Reflected-Heat Tolerant)   ✔ Drought-Tolerant   ✔ Evergreen   ✔ Low-Maintenance

Plant It With

• Regal Mist (Pink Muhly Grass): soft pink fall plumes play beautifully off the burgundy foliage.
• Mexican Thread Grass: fine airy golden blades give a light contrast to the bold purple.
• White Cloud Muhly Grass: white feathery plumes create a striking color contrast.
• Desert Spoon: silver-blue rosettes make the deep burgundy color pop.

Is Purple Fountain Grass Right for Your Yard?

It thrives in full sun and reflected heat, grows in any well-draining desert soil once caliche is opened up, and needs little water once established, making it the go-to grass for bold year-round color and movement. Give it a warm spot and one annual late-winter cutback. It is not the right pick for frost-pocket low spots without protection, and near desert washes or wildland edges you should deadhead the plumes to limit any reseeding.