Justicia aconitiflora (A.Meeuse) Cubey
Common names: yellow pistolbush, lemon pistolbush (Eng.); geelpistoolbos, lemoenpistoolbos (Afr.)
SA Tree No: 681.2
A beautiful shrub with fresh green foliage and showy pale yellow flowers in autumn, suitable for sun, semi-shade or shade. This species was for many years known as Duvernoia aconitiflora.
A branched, rounded, evergreen shrub or small tree, 1-3 m tall, usually multi-stemmed. Young branches are quadrate and hairy. Leaves are light green, shiny, opposite, narrowly elliptic to lanceolate, up to 150 mm long and 55 mm broad, with a shortly decurrent base, like a revolute wing.
Inflorescence is an elongated terminal spike of up to 7 flowers, with a rachis that is up to 130 mm long. The peduncles are quadrate, covered with short, stiff, adpressed hairs (strigose) and 30–50 mm long. Bracts are broadly ovate, 5 × 2 mm, and fall off before the petals even open (caducous). Flowers are in pairs; they are sessile and densely covered with short hairs (tomentose). Corolla tubes are channeled on the undersides (abaxially) and 2-lipped. The upper lip is broadly ovate, strongly boat-shaped and as long as it is broad. The lower lip is transversely oblong. The ovary is densely covered in fine, soft hairs (velutinous). The flowers are pale yellow to cream-coloured, marked with purple in the throat, and are borne in autumn to winter (May to August).
The fruit is a club-shaped capsule, up to 25 mm long that dehisces explosively, releasing the seeds in winter to early summer (May to November).
According to the Red List of South African plants, accessed on the 12 December 2017, Justicia aconitiflora is Least Concern (LC).
Distribution and habitat
Justicia aconitiflora grows on forest margins, sometimes along rivers, in Mpumalanga and KwaZulu-Natal, and also in Swaziland and southern Mozambique, mainly along the Lebombo Mountains.
Derivation of name and historical aspects
The genus Justicia is named after James Justice, 1698-1763, a Scottish horticulturalist. The species name aconitiflora means ‘with flowers like the genus Aconitum’, commonly called monkshood or wolfsbane. The common name pistol bush, which is also used for J. adhatodoides, is derived from the sharp cracking sound of the dehiscing seed capsules. Lemon pistol bush refers to the pale yellow colour of the flowers. The former genus Duvernoia was named after a German botanist J.G. Duvernoy, who was a student of Tournefort, who wrote Flora of Tubingen, in 1722.
Duvernoia was, until recently, regarded as a separate genus of only 2 species, both now included in Justicia: J. adhatodoides and J. aconitifolia. These evergreen shrubs are indigenous to tropical and southern Africa, widely distributed in parts of Mpumalanga, KwaZulu-Natal and Eastern Cape, and in Swaziland.
Justicia is a large and variable genus containing about 600 species spread throughout the world. The current thinking is to follow the broad view of Justicia, which now encompasses many smaller genera, including Duvernoia, which is now sections within Justicia.
The flower is lightly scented and attracts insects, such as bees, which makes them potential pollinators. Sunbirds are also said to visit the flowers. The fruit is a club-shaped capsule that releases its seeds explosively. This disperses them quite far from the mother plant and maximizes the potential of spreading them even further by wind.
No cultural uses are known for this species.
Growing Justicia aconitiflora
Justicia aconitiflora thrives in semi-shade or in deep shade and marshy understorey. It requires moist soils and hates to be dried out inbetween watering. It sheds its leaves in winter and is frost tolerant. It is a very low maintenance shrub, and may be pruned to remove dead branches, or just to give it a pleasing shape.
The lemon pistolbush is very easy to propagate by both cuttings and seeds. At Kirstenbosch National Botanical Garden, we have grown this species from seeds sown in spring (September) with 100% germination. A sowing mixture 50:50 sand and fine-milled bark was used and the trays were placed in a warm, sunny, well ventilated, north-facing structure. The watering was done 3 times a week by hand to keep the trays moist, but not wet. Vegetative propagation should be easy as well, from semi-hardwood cuttings taken in early summer, treated with a rooting hormone and placed in a propagating unit with heated benches under intermittent mist.
- Boon, R. 2010. Pooley's trees of eastern South Africa, a complete guide. Flora & Fauna Publications Trust, Durban.
- Goldblatt, P. & Manning, J.C. 2014. Nomenclatural adjustments in African plants 1. Bothalia 44(1) 9 pages.
- Pienaar, K. (ed.). 2002. The ultimate book of trees and shrubs for southern Africa. Southern Book Publishers, Pretoria.
- Plantbook, Duvernoia aconitiflora. http://www.plantbook.co.za/duvernoia-aconitiflora/ accessed 12 December 2017.
- Victor, J.E. & Van Wyk, A.E. 2005. Duvernoia aconitiflora A.Meeuse. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2017/12/20.
- Manning, J.C. & Getliffe Norris, F.M. in Flora of southern Africa, via POSA http://posa.sanbi.org/flora/results_browse.php?src=FloraSA&taxon=genno=3935 accessed 12 December 2017
- Wentzel, J. Operation Wildflower, Gallery, Duvernoia aconitiflora. http://www.operationwildflower.org.za/index.php/component/joomgallery/shrubs/duvernoia-aconitiflora-flower-by-jw-1432 accessed 12 December 2017.
Kirstenbosch National Botanical Garden
January 2018, updated July 2019
Plant Type: Shrub, Tree
SA Distribution: KwaZulu-Natal, Mpumalanga
Soil type: Sandy, Loam
Flowering season: Autumn, Winter
PH: Acid, Neutral
Flower colour: Cream
Aspect: Full Sun, Shade, Morning Sun (Semi Shade), Afternoon Sun (Semi Shade)
Gardening skill: Easy