Amongst the attractive red, bronze tints provided by tree foliage in autum, Barleria obtusa makes an even more spectacular show. This evergreen flowering shrublet is covered in a mass of dainty violet flowers from April to May. This fast growing, spreading shrublet is a must for rockeries and small gardens.

B.obtusa occurs naturally from the Soutpansberg in the Northern Province, Mpumalanga, and KwaZulu Natal and further to the Eastern Cape Province. It grows quite commonly on hills and along forest margins in subtropical regions.

Barleria obtusa is multi-stemmed shrublet. The branches have an erect or decumbent habit. The size of the plant varies when planted in different growing environments. From about one metre as a low bushy plant in the open, whilst shady conditions encourage long sprawling branches which reach a height of two metres.

The soft, sage green leaves are oppositely placed and have entire margins with fine translucent hairs. A characteristic feature is that the leaves are reflexed (the margins are upturned). In its natural habit the leaves of the bush violet are browsed by buck.

The 2-3cm wide flower petals are borne on the top part of the branch. A closer look at the individual flower will reveal the style and only two stamens with violet coloured pollen. The seed capsule becomes woody when mature, and then the seeds are explosively released and scattered on the ground.

Growing Barleria obtusa

Barleria obtusa grows very well in full sun and semi- shaded conditions. Although B. obtusa is a summer rainfall subject and can grow in a wide range of soils, it thrives in the winter rainfall, W. Cape area but requires well drained soil conditions. Lots of compost added to the soil will give plants a good boost.

The bush violet also shows good drought resistant properties, however, for excellent growth, regular watering is encouraged.

The shrublet can be planted in mixed borders and banks. Regular pruning is necessary after the shrub has flowered, for neat and compact growth. To encourage more flowers, nip off the shoots during spring and early summer.

B. obtusa is easily propagated from seeds, cuttings and layering. The seeds must be collected before the seeds are dispersed, when the seed capsules turn brown in color. The flat seeds are sown in seed trays in a well- drained medium. Cover the seeds with sifted soil or sand. Keep trays in a shaded area.

Semi-soft wood cuttings can be taken during the summer from new growth. Dip the base of tip or stem cuttings into Serradix No. 2 hormone powder to stimulate fast root development. Successful results can be expected in four weeks.

Layering is also an easy method of multiplying this plant. Choose a long branch which has not flowered. In autumn prepare the soil, by filling a small hole with coarse sand. Bend the branch and remove the leaves of the area that touches the soil. Score the underside of the naked stem to injure the tissue. Peg the bent branch into the hole and cover it with soil and coarse sand. Stake the tip and keep the spot moist until rooted.

In habitat B. obtusa is variable with different forms. White and pink flowered forms have been introduced into cultivation. Barleria 'Purple Prince' has a spreading habit with darker violet flowers and has slightly glossy leaves. This cultivar is very popular and a garden asset for difficult areas.

Barleria is a large genus composed of 120 species mostly confined to Africa and in tropical Asia. There are about 50 species found in South Africa. In the recent past new species have been discovered, such as B. greenii from Natal. This genus bears investigation as several other Barleria species also exhibit horticultural potential.

References

• Alexander, M. Blues and Mauves, Aug. 1994, SA. Garden & Home
• Johnson, D. & Johnson, S. Indigenous trees and shrubs for your garden
• Maclear, R. Indigenous Acanths for your garden. June 1998, SA. Garden & Home
• Wild flowers of SA. 3 Take your pick (Barleria) Sept.1994, Farm Week

Megan Isaacs
Kirstenbosch NBG.
28 April 2020