# Desert grass (Pennisetum divisum)

Canonical: https://plantguide.ae/plants/desert-grass · Updated: 2026-09-30
Source: Ghaf Gardens (https://plantguide.ae/plants/desert-grass)

Desert grass · ثمام · also called Desert fountain grass, Thumam  
ornamental-grass · native · family Poaceae · grows 0.4–1.2 m tall, 0.4–0.8 m wide · slow growth  
full sun · very low water need  
Ratings for Dubai (1–5, 5 is best): heat 5 · salt 4 · drought 5 · shade 1 · ease of care 5  
Sow or plant: Sep–Dec  
Uses: specimen, native-habitat, groundcover  
Garden styles: desert-modern

A native, clump-forming desert grass that survives on rainfall alone in the wild — not a lawn grass, but a tough, low-water accent for desert-modern planting.

## About

Meet desert grass, a plant that never needed a garden to prove itself. Long before anyone planted it deliberately, ecologists surveying Al Ain's Wadi Tarabat found it to be the single most important species in that stretch of desert — not the showiest, just the one doing the most work holding the ecosystem together, anchoring loose sand against the wind with nothing but whatever rain happened to fall.

Its character in a garden is loose and unruly compared with the trimmed hedges and mown lawns around it — a woody-based clump of fine blue-green blades that arch and sway rather than sit still, topped in spring with soft, bristly flower spikes that catch low light beautifully. Where most of Dubai's planting aims for tidiness, desert grass offers something closer to honesty: this is roughly what the ground here actually wants to grow.

What it brings to the mood of a garden is movement and a sense of place. It sways in a breeze that barely stirs a clipped hedge, and drifted through gravel or beneath a light canopy it reads as a deliberate nod to the desert the whole city is built on, rather than an import pretending otherwise.

Desert grass grows wild across the UAE's sandy plains, rocky slopes and wadi beds, from Abu Dhabi to Dubai, Sharjah and Fujairah. Reviews of UAE native vegetation record it as one of the most important species in some of the country's protected desert ecosystems — in Al Ain's Wadi Tarabat, for example, it was found to have the highest importance value of any plant surveyed — because it anchors loose sand and survives on whatever rain falls, with no supplemental irrigation at all.

It grows as a woody-based, arching clump of fine, blue-green leaves up to about 1.2 m tall, topped with soft, bristly cream-to-purple flower spikes in spring. Unlike the turf grasses on this list, it is not mown into a lawn — it is planted as a specimen or drift in gravel, rock gardens and naturalistic desert-modern schemes, where its loose form and pale colour read as a deliberately wild counterpoint to clipped hedges and lawn.

Because it is a genuinely wild desert plant rather than a bred turf cultivar, hard numbers on salinity and irrigation tolerance are limited — but its natural habitat on saline desert soils and dry wadi beds says plenty on its own. Pair it with [Ghaf](https://plantguide.ae/plants/ghaf.md) or [Hopbush](https://plantguide.ae/plants/hopbush.md) for a low-water native planting scheme, or as underplanting where a light canopy still lets enough sun through.

## Through the year

Desert grass follows the desert's own rhythm rather than a garden calendar. Plant in the cool season (September–December) so roots settle before summer heat. Winter rain, when it falls, triggers fresh leaf growth through March–April, and established clumps send up soft, bristly cream-to-purple flower spikes from February through April — the plant's one real seasonal display. An optional hard cut-back to around 150–200 mm in February tidies the clump and refreshes it for spring, though leaving it uncut looks equally at home in a naturalistic planting. Through summer it simply holds on with minimal or no supplemental water, exactly as it does in the wild.

| When | What | Note |
| --- | --- | --- |
| Sep–Dec | Plant: Best planting window | Plant in the cooler months so the root system establishes before summer heat. |
| Feb–Apr | Flowers: Bristly flower spikes | Cream to purple-tinged flower spikes appear on established clumps in spring. |
| Mar–Apr | New growth: Fresh leaf growth after winter rain |  |
| Feb | Prune: Cut back for tidiness | An annual hard cut-back to around 150–200 mm keeps the clump neat and encourages fresh growth; not essential, but tidier for a garden setting than leaving it wild. |

## Care in Dubai

- **Watering in summer:** Established plants need very little supplemental water; an occasional deep soak is usually enough on top of whatever rain falls.
- **Watering in winter:** Rainfall alone is often sufficient; irrigate only in a prolonged dry spell.
- **While establishing:** Water every few days for the first couple of months until the root system is established.
- **Soil:** Thrives in poor, sandy or rocky, free-draining soil typical of UAE desert ground — avoid rich, moisture-retentive beds.
- **Feeding:** None needed; it is adapted to nutrient-poor desert soils.
- **Pruning:** An optional annual cut-back to around 150–200 mm in late winter tidies the clump and refreshes growth for spring.
- **Planting:** Plant in the cooler months (September–December) in full sun on free-draining ground; space clumps 0.4–0.8 m apart.
- **Pests and problems:** Generally trouble-free

## Good and bad

**Pros**
- Native to the UAE and adapted to survive on rainfall alone once established
- Anchors loose sand and helps stabilise slopes, as it does in the wild
- Essentially maintenance-free — no mowing, little feeding, minimal pest trouble
- Soft, pale, naturalistic texture that suits desert-modern and native planting schemes
- Thrives in reflected heat and poor soil where lawn grasses would fail

**Cons**
- Not a lawn substitute — it grows in loose clumps, not a walkable mat, and doesn't tolerate foot traffic
- Needs full sun; thins out in shade
- Slow to bulk up from a young plant
- Little UAE-specific data exists on its irrigation or salinity tolerance beyond its wild habitat

## Common mistakes

- Trying to use it as a lawn substitute. It grows in loose, arching clumps rather than a spreading mat and doesn't tolerate foot traffic or mowing the way a turf grass does.
- Planting it in a rich, regularly irrigated bed alongside thirstier ornamentals. It performs best, and looks most like itself, in the poor, free-draining desert soil it evolved for — generous water and feeding push it toward a floppier habit.
- Crowding clumps close together for a fuller look early on. It's slow to bulk up, and tight spacing just means more competition for water and light while it establishes.
- Watering it on the same schedule as nearby lawn or ornamental beds. It needs very little supplemental irrigation once established, and consistent overwatering works against its naturally drought-adapted habit.

## Good to know

- A survey of Al Ain's Wadi Tarabat found desert grass to have the highest importance value of any plant species recorded there, reflecting how central it is to that desert ecosystem.
- It genuinely survives on rainfall alone in the wild, with no supplemental irrigation, which is why an established garden specimen needs only occasional deep watering on top of whatever rain falls.
- As a wild desert species rather than a bred turf cultivar, there is limited UAE-specific data on its irrigation-grade salinity tolerance — its performance on saline desert soils in the wild is the best available evidence.
- Its traffic tolerance is rated at the very bottom of the scale, underlining that it is a specimen and drift plant, never a lawn substitute.

## Using it in a garden

Roles: Specimen drift in gravel, Naturalistic desert-modern planting, Slope or dune stabilisation, Light underplanting beneath a high canopy

Use it where a garden wants to read as genuinely desert rather than imported — drifted through gravel, massed on a slope that needs stabilising, or as loose underplanting beneath a high, light canopy like a date palm where enough sun still reaches the ground. It needs full sun and free-draining, even poor soil to perform at its best; a rich, irrigated bed works against its natural habit. Give clumps room (0.4–0.8 m apart) to reach their full arching form rather than crowding them for instant fullness.

- [Ghaf](https://plantguide.ae/plants/ghaf.md): Both are UAE natives adapted to the same rainfall-only conditions, giving a planting scheme genuine ecological and visual coherence.
- [Hopbush](https://plantguide.ae/plants/hopbush.md): A similarly tough native shrub that shares desert grass's low-water, poor-soil preferences for a layered native planting.
- [Samr](https://plantguide.ae/plants/samr.md): Pairs naturally in a native desert-modern scheme, with desert grass's soft, low texture offsetting samr's more structured form.

## Lawn facts

- Mowing height 150–200 mm · traffic tolerance 1/5
- Salinity: Grows naturally on saline desert soils and dry wadi beds, suggesting good tolerance, though it hasn't been tested against irrigation-grade salinity the way turf cultivars have.
- Shade: Poor — a full-sun desert plant that thins out and loses form in shade.

## FAQ

**Can I use desert grass as a lawn?**  
No — it grows as loose, arching clumps rather than a spreading mat, and doesn't tolerate being walked on or mown short. It's a specimen or drift plant for gravel and rock gardens, not a lawn substitute.

**Does desert grass need any watering in Dubai?**  
Very little once established. In the wild it survives entirely on rainfall across the UAE's sandy plains and wadi beds. In a garden, an occasional deep soak in the hottest months keeps it looking fuller, but it isn't essential.

**Why plant a native grass instead of a lawn grass?**  
It uses a fraction of the water, needs no mowing or feeding, and supports the same desert ecosystem it's part of in the wild — useful as an accent or ground-stabilising planting around a smaller, more water-efficient lawn rather than as a replacement for one.

**Does desert grass need full sun, or will it tolerate some shade?**  
It needs full sun to hold its tight, arching form and thins out noticeably in shade, consistent with its open, unshaded wild habitat on plains, slopes and wadi beds.

## Related plants

[Ghaf](https://plantguide.ae/plants/ghaf.md) · [Samr](https://plantguide.ae/plants/samr.md) · [Hopbush](https://plantguide.ae/plants/hopbush.md) · [Bermuda grass](https://plantguide.ae/plants/bermuda-grass.md)

## Photos

![Desert grass and clipped shrubs in a corten-edged bed in a desert-modern Dubai garden](https://plantguide.ae/images/generated/styles/desert-modern/a-hero-v2.webp)

## Sources

- [uaeflora.ae: Pennisetum divisum](https://uaeflora.ae/plant/244)
- [Landscaping with native plants in the UAE: A review (Emirates Journal of Food and Agriculture)](https://www.ejfa.me/index.php/journal/article/download/319/1037)