Agapanthus praecox subsp. orientalis
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
Agapanthus praecox subsp. orientalis plants occur naturally mostly in full sun on
rocky outcrops in the
Durban area
at an altitude of about 1500 feet where they grow in very shallow soils
mostly with
little or no competition from other plants.
Growth habit
These
plants are fairly large to medium growing evergreen and clump forming
that
reproduce naturally by means of seed
Decorative value
These
plants are most decorative having dark glossy green leaves and a very
neat
growth habit, they produce spectacular blue flowers in profusion in
early to
mid summer
Drought resistance
In their
natural habitat they are able to withstand long periods of drought
probably due
to the very large succulent root mass which is quickly able to store
large
amounts of water.
From my
experience of growing these plants as pot plants I have found them to
be very
drought resistant.
Disease and pest resistance
Agapanthus plants
are generally very disease resistant being attacked on occasion by a
borer
caterpillar in particularly when they are growing luxuriously as occurs
when
they are provided with large amounts of nutrient and water. Flower
spikes are
can also be attacked by fungus during periods of very warm wet weather
which
prevents the flowers from opening.
Suitability as Green Roof plants
These
plants are medium to large plants which do not like competition from
more vigorously
growing plants. They are probably best suited as feature plants, but
could
possibly be planted en mass. These plants are most probably best
established
from splits or mature plants.
Under our
test conditions where these plants have not been under competition from
more
vigorous growing plants they are showing good results.
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 solitary bees.
Cautions and precautions in the
Green Roof
application
None that I
am aware of at the moment
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