Aloe arborescens occur naturally mostly in full sun on many rocky outcrops in the Durban area where they grow in very shallow soils mostly with little or no competition from other plants.

Growth habit
These plants are medium to large growing evergreen clump forming plants that primarily reproduce by means of seed.

Decorative value
These plants are extremely decorative feature plants having grey green leaves and a neat growth habit, they produce masses of very attractive orange flowers during the winter months. In winter the and when they are moisture stressed the leaves in particular the leaf margins turn a distinct pink colour.

Drought resistance
In their natural habitat they are able to withstand very long periods of drought due to their succulent nature. From my experience of growing these plants as pot plants I have found them to be very drought resistant.

Disease and pest resistance
These plants are generally disease resistant, although they are sometimes attacked by scale and ants can create a problem by introducing mealy bug to the roots.

Suitability as Green Roof plants
From my experience with these plants and from indications of plants that are being tested under Green Roof conditions these plants certainly give the impression that they are going to be first rate Green Roof feature plants where larger plants are able to be grown.

Biodiversity value in the Green Roof landscape
They create robust habitat and protection for other green roof dwellers. Their flowers attract pollinating insects in particular honey bees and Sunbirds.

Cautions and precautions in the Green Roof application
They have very vigorous root systems so good root protection must be provided to protect the water proof membrane. Under certain circumstance they may need to be pruned from time to time.