How to grow tree aloe
Overview
Tree aloe (Aloidendron barberae) is a large, branching succulent tree from southern Africa, grown in Australian gardens as a dramatic architectural feature. It produces tall, candelabra-like flower spikes in winter and thrives in hot, dry conditions. Despite its size, it is a herbaceous perennial that requires excellent drainage and minimal water.
Soil Preparation
Tree aloe requires a neutral to slightly acidic pH (6.0–7.5) and extremely well-drained soil. Before planting, mix in 30% coarse sand or pumice if your soil is clay. A raised bed or mound is ideal for improving drainage in wetter climates.
Growing Guide
Plant tree aloe in full sun in a position with plenty of space—it can reach 10–15 m tall and 5–8 m wide. Choose a site with very free-draining soil, ideally sandy or gravelly; amend heavy clay with coarse sand or pumice. Dig a hole twice the width of the root ball, backfill with native soil, and water in once. Space specimens at least 5 m apart to allow for mature spread. Do not plant in low spots that collect water.
Care
Feed tree aloe with a balanced slow-release fertiliser (e.g., 8-4-6) in early spring at half the recommended rate. Prune only to remove dead or damaged branches; avoid heavy cutting that can leave stubs prone to rot. Keep mulch at least 30 cm away from the trunk to prevent collar rot.
Companion Planting
Pair tree aloe with other drought-tolerant succulents like Agave americana, Aloe ferox, or Euphorbia ingens. Underplant with low-growing groundcovers such as Carpobrotus (pigface) or Sedum species. Avoid planting near moisture-loving plants or lawns that require regular irrigation.
Common Pests & Risks
Scale insects and mealybugs are the most common pests on tree aloe in Australia. Treat with a horticultural oil spray or systemic insecticide applied in early spring. Check leaf axils and branch crotches for infestations; prune out heavily affected stems.
Troubleshooting
Yellow leaves: overwatering or poor drainage—reduce watering and improve soil. Brown leaf tips: salt burn from fertiliser—flush soil with water. Soft, mushy stem: root rot from wet soil—remove affected plant. Slow growth: insufficient sun or compacted soil—relocate to full sun. Leaf drop: cold damage—protect with frost cloth in winter.