Pycnostachys reticulata is a beautiful perennial with spikes
of two-tone, pale blue and mauve flowerheads in late summer to autumn;
a good choice for the mixed border if you live in a frost-free area.
reticulata is a robust, upright-growing, herbaceous shrub that
reaches a height of 1.5 to 2 m. The leaves are opposite, narrowly
lanceolate, with irregularly toothed margins and a very short stalk.
When they are both not in flower, P. reticulata could be
mistaken for Leonotis
leonurus as they have a similar growth habit and similar-looking
Pycnostachys reticulata has pale blue and mauve flowers
densely crowded into short, spiky spikes, about 50 mm long and 20
mm wide. The inflorescence is terminal on the main or lateral branches.
The spikiness comes from the fact that the calyx is made up of 5
spike-like lobes that protrude beyond the buds and are a noticeable
feature of the inflorescence. The inflorescence is made up of mauve-blue
buds amongst the reddish-purple spikes of the calyx. The flowers
open from the bottom of the inflorescence upwards, forming a pale
blue ring around the inflorescence. If you look closely you can
see that the flowers are typically salvia-like: - a two-lipped tube.
The lower lip is large and boat-shaped and longer than the upper
At Kirstenbosch the plants show some variation in colour, some have
pale mauve flowers with pinkish-purple calyx spikes, and at the
other end of the scale they have dark reddish-purple spikes and
bluish-mauve flowers. Flowering time at Kirstenbosch is late-summer
to autumn (March-April). The seed is a small, ovoid nutlet.
Pycnostachys reticulata is the most widespread of the southern
African Pycnostachys species. It occurs in the Eastern Cape,
KwaZulu-Natal, Swaziland, Mpumalanga, Gauteng, North West, Limpopo
and northwards as far as Tanzania. It grows in moist, swampy places
and in grassland.
are 37 species of Pycnostachys that occur in tropical Africa
and Madagascar. Only three species occur in southern Africa: P.
reticulata, P. urticifolia and P. coerulea. At Kirstenbosch
we grow only the two former species. P. urticifolia is commonly
known as the nettle-leaved pycnostachys, dark blue pycnostachys,
blue boys or hedgehog sage, ystervarksalie (Afr.) and amadata
or unkungwini (Zulu). Its leaves are markedly different, greener,
broader, almost triangular with rounded teeth and the flowers are
a bright gentian blue or pale blue or white. It occurs in moist
places along grassy streambanks and forest margins in Limpopo, Mpumalanga
as well as Zimbabwe, Mozambique and Tanzania.
Derivation of the name
The genus name Pycnostachys is derived from the Greek pyknos
meaning dense, and stachys actually an ear of corn but in
botany a spike, referring to the inflorescence, which is a spike
of many flowers densely crowded together. The species name reticulata
means a fish net, or netted or a network in Latin, and refers to
the veins, which are clearly visible on the underside of the leaf.
Pycnostachys reticulata is a larval food plant for the Marsh
Commodore butterfly, Precis ceryne and the flowers are visited
Uses and cultural aspects
Pycnostachys reticulata roots are used in traditional medicine
as a mouthwash for teeth suffering from neuralgia (nerve pain),
not decay. In the Democratic Republic of the Congo, a species indigenous
to that region, P. erici-rosenii is used in traditional medicine
in combination with other plants to treat rabies, madness, anaplasmosis,
gastro-enteritis, diarrhoea, dysentery, coccidiosis and schistosomiasis.
Growing Pycnostachys reticulata
Pycnostachys reticulata is easy to grow, not that fussy
about soil and can withstand periods of drought, but does best in
fertile, well-drained soil in full sun or part shade with ample
water. It can be pruned hard after flowering and it will resprout
strongly in the spring. Although it is frost tender, it should be
able to survive short cold snaps but not prolonged exposure to freezing
Pycnostachys reticulata is a good plant for the mixed border,
where it provides a striking two-tone colour effect. The flowering
stems are long and good for cutting.
It can be propagated by seed sown in spring or early summer, or
by heel or tip cuttings taken in spring or early summer.
- Hutchings, A. 1996. Zulu medicinal plants, an inventory.
University of Natal Press, Pietermaritzburg.
- Leistner, O.A. (ed.). 2000. Seed plants of southern Africa:
families and genera, Strelitzia 10.
- Pooley, E. 1998. A field guide to wild flowers of KwaZulu-Natal
and the eastern region. Natal Flora Publications Trust, Durban.
- Chifundera, K. 1998. Livestock diseases and the traditional
medicine in the Bushi area, Kivu Province, Democratic Republic
of Congo. African Study Monographs, 19,1: 13-33.
- Pole Evans, I.B. 1933. Pycnostachys purpurascens. The Flowering
Plants of South Africa 13: t. 513.
Kirstenbosch National Botanical Garden