Is one of a number of plant species which are presently being tested
for their suitability to be grown as Green Roof plants in the Durban
region that have initially shown good results. They all occur naturally
within a radius of 50 km of the Durban city centre
Crassula alba is found growing on and
amongst rocks in
grassland in full sun in the Durban
alba is rosette forming succulent
that produces a tall flat topped flower head.
Crassula alba reproduce naturally by
means of seed. In
cultivation this plant is best propagated from seed, large clumps can
also be subdivided.
plants are being grown for their very attractive growth form as well as
their very attractive flowers.
plants are very drought resistant.
Disease and pest resistance
susceptible to attack by two species of Lycaenidae Butterfly the
Common Black Eye Gonatomyrina
gorgias gorgias and the Tailed Black Eye Leptomyrina hirundo which use them as
larval host plants.
Suitability as Green Roof plants
plants are valuable ground covers because of their dwarf growth habit,
the ease with which they establish themselves and their rapid growth
habit. Under green roof conditions they have displayed extreme heat and
tolerance and the ability to grow in very shallow dry soils. Crassula
alba reproduces it's self freely from seed.
Biodiversity value in the Green
Their profusion of
small red flowers which are produced in a large flower head have
an extensive flowering period attracting large numbers of insects in
particular the honey bee.
Cautions and precautions in the Green Roof
must be taken to ensure good drainage to prevent rotting