Family: Polygalaceae (milkwort family / false
legume family/ butterfly bush family)
Common names: butterfly bush, ertjiebos (Afr.)
Many people are familiar with the hardy coastal shrub, Polygala
myrtifolia which is useful addition to indigenous gardens. Kirstenbosch
staff have now selected a form of Polygala fruticosa, a similar
species, which makes an even better garden plant. This selected
form has been given the name 'Southern Shores'.
The original plant was found growing out of rocky fissures so close
to the sea that the plants were being splashed with salt water at
high tide. What attracted us was the unusually compact growth habit,
the pointed, heart-shaped, blue-green leaves and the masses of intensely
purple flowers. Plants grown at Kirstenbosch have retained this
lovely compact growth habit and leaf colour.
P.fruticosa 'Southern Shores' is a neat, rounded shrub up
to 1 m tall. The young leaves of this indigenous evergreen are tinged
with purple, the shade echoed by the deep purple, winged flowers.
Peak displays of flowers occur from spring to early summer, giving
an unequalled show. It also produces a scattering of blooms throughout
the year. Bees are particularly attracted to the nectar that the
flowers produce and are the main pollinators. Seeds are enclosed
in papery, flattened capsules that remain on the bush for quite
some time during and after flowering.
The truly lovely flowers superficially resemble those of the pea
and legume family but are actually quite different. All members
of this genus have three to five sepals and three to five petals.
The two lateral sepals are petal-like, larger than the others, coloured
like the petals, and resemble the wing petals of a pea flower. The
lower petal is boat-shaped and encloses the eight stamens and the
style, and resembles the keel of a pea flower. A characteristic
of all polygalas that makes them easily distinguishable from the
pea is the brush-like tuft on the lower, keel-like petal. Closer
inspection also reveals that the flowers do not have a large standard
petal (also called the banner) like pea flowers do. Another distinguishing
difference is that polygalas do not bear leguminous fruit.
The name Polygala is derived from classical Greek polys
meaning much and gala meaning milk, so named because the
plants were believed to enhance milk production in livestock. The
specific name fruticosa means shrubby or bushy in Latin.
Polygala fruticosa is a native of South Africa, growing on
mountain slopes and coastal hills from the southern Cape to the
Karoo and KwaZulu-Natal. It tolerates a range of soils, from clay
to rocky sandstone.
Members of the family Polygalaceae occur nearly world-wide in 17
genera, with 950 species. Of the 400-450 southern African species,
32 occur in the Cape region. The genus Polygala consists
of about 600 species that occur in temperate and warm regions of
the world. There are 232 species of Polygala in Africa and Madagascar,
approximately 88 of which occur in southern Africa.
Growing Polygala fruticosa
This hardy plant requires no special care. Good, enriched soil,
full sun or semi-shade and plenty of water, will ensure rapid, healthy
growth. It has excellent waterwise properties, and once established
it will tolerate fairly heavy drought.
It is ideal as a specimen plant grown to brighten up any patch
in your garden. It is a lovely container plant and it will also
do well in a mixed border, providing attractive flowers and/or foliage
all year round. The 'Southern Shores' selection grows very well
in rockeries, on slopes, terraforce walls and any well-drained,
sunny garden position providing a beautiful display. As it grows
naturally next to the sea it is also an ideal small shrub for coastal
Polygala fruticosa is freely self-seeding and small plants
will appear around the parent plant after the first flowering season,
and these will transplant easily. Seed is typical of Polygala
being a small, hard, oval, black seed. Treat seed with hot water
for better germination. Light scarification and treatment with pre-emergence
fungicide will give optimum results, but is not necessary for good
Polygala fruticosa can also be propagated vegetatively using
tip or heel cuttings, preferably taken during spring or autumn.
Pruning is not necessary as it retains a compact habit, but when
cultivated in bags they may be pruned and will readily resprout
from medium to hard pruning done on the young wood.
Other recommended species
the September butterfly bush, is a hardy, quick-growing coastal
shrub with lime-green leaves producing masses of purple-pink
flowers, mainly from spring to summer.
Polygala virgata, purple broom, is a sparse
shrub with arching branches, bearing graceful sprays of deep
purplish pink flowers.
Cherise Viljoen and Anthony Hitchcock
Kirstenbosch Botanical Garden