Groundcover
Trailing Acacia
Acacia redolens 'Desert Carpet' · Fabaceae
Also called: Prostrate Acacia, Desert Carpet Acacia, Bank Catclaw, Vanilla-scented Wattle
Trailing Acacia (Acacia redolens 'Desert Carpet') is a very low-water groundcover well suited to Tucson and the low desert. It grows to 1-2 ft H x 8-15 ft W in full sun, with a fast growth rate.
Trailing Acacia at a glance
- Water use
- Very Low (established)
- Sun
- Full sun; tolerates intense reflected heat.
- Mature size
- 1-2 ft H x 8-15 ft W
- Growth rate
- Fast
- Bloom
- Pale to bright yellow puffball flowers, Late winter into spring (February-April)
- Cold hardiness
- Hardy to about 15-20 F (USDA Zone 8b-9); tip damage possible in hard freezes.
- Soil
- Tolerates most soils including poor, rocky, and alkaline caliche soils; requires good drainage and tolerates salinity.
- Native range
- Western and southern Australia
- Best used as
- Large-area and slope groundcover, Erosion and bank stabilization, Freeway/commercial mass plantings, Low-water groundcover for large spaces
- Wildlife
- Spring flowers provide pollen/nectar for bees; provides low cover for small wildlife.
- Toxicity
- No significant toxicity reported for landscape use; some Acacia species can cause mild issues if ingested in quantity by livestock.
How to grow Trailing Acacia in Tucson & the low desert
Watering
Very drought tolerant once established; water deeply but infrequently, about every 2-4 weeks in summer and rarely in winter. Deep, infrequent irrigation promotes deep rooting and a flatter, healthier habit; frequent shallow water causes mounding and root problems.
Fertilizer & nutrients
None to very little; as a nitrogen-fixing legume it needs no supplemental nitrogen and thrives in poor desert soils.
Pruning & care
Prune to remove any upright, reverted, or woody stems that mound up and to maintain the low spreading form; avoid shearing into formal shapes. Remove dead/frost-damaged wood in spring.
Notes
'Desert Carpet' is a low, dense, intensely prostrate selection of Acacia redolens, ideal for covering large slopes and dry banks with minimal water once established. Note that A. redolens has NOT been reclassified to Vachellia (that change applied to the spinescent African Acacia s.s. group), so Acacia redolens remains the accepted name. Best on large sites; too vigorous for small spaces. The straight species can mound higher than the 'Desert Carpet' cultivar.
Sources: AMWUA 'Landscape Plants for the Arizona Desert'; Mountain States Wholesale Nursery; Arizona State University (C. Martin) desert plant database; University of Arizona Cooperative Extension