Its heavenly blue to purple flowers resemble fanciful butterflies, hence its common name "blue butterfly bush." The fluttering flower panicles sprout from the ends of long arching branches, and each flower has one violet-blue petal and four pale blue ones, framed by long purple anthers which bend elegantly upwards, hence its other common name "blue cat's whiskers".

The plant will bloom almost continuously from spring to autumn, but typically flowers most heavily when the temperatures cool down in autumn. The flowers are a firm favourite with carpenter bees and lure butterflies with their nectar; and the showy, black fleshy fruits are devoured by birds and monkeys.

The dark green evergreen leaves give a wonderful tropical feel to the garden all year round, but when crushed they have a pungent, even rank smell. This smell is what makes the bush repellent to most insects and pests, which in return, reduces the need for spraying in the garden.

The blue butterfly bush remains a highly sought after garden plant for tropical and subtropical gardens alike. However, if you live in the colder regions of the country, and simply have to try one, the good news is Rotheca myricoides will tolerate much colder conditions than most tropical plants, as long as it is planted in a warm and protected position in the garden, or perhaps in a pot which can be moved in winter.

Picture courtesy www.newplant.co.zaIts new Latin name is Rotheca myricoides, and Rotheca is a member of that quite large Lamiaceae or mint family, but until 1998 Rotheca wasn't really a recognized genus until phlogenetic DNA analysis set things straight. The genus comprises of about 30 species, and members include shrubs, perennial herbs, and a few lianas and small trees.
 
The blue butterfly bush is native to tropical Africa and is particularly abundant in Kenya and Uganda, but can also be found wild in Limpopo, Mpumalanga, and KwaZulu-Natal. It is commonly found growing in sheltered groves in rocky places, or along hillsides and river banks, open woodlands and along the margins of evergreen forests, shrubby bushveld, and in coastal bush, from Natal to Transkei, at elevations of up to 1400m.

Because the butterfly bush is a sprawling evergreen with a weak upright growth habit, it is often listed as a vine, although it is far too rangy or bushy to be considered a true vine. In the garden, the plant grows quickly and varies in height and spread. If left un-pruned, and in warm regions, it can reach 2 to 4m tall with an equal spread, but it can easily be pruned at any time to keep it smaller, and amazingly, it will be flowering once again within three to four weeks!

Uses:

The edible fruits are taken as a remedy for skin ailments. The bark has numerous antifungal properties, and is crushed to a powder after which it is used to treat snakebites, reduce bodily swellings and relief indigestion. It is also used to treat colds, chest pains and headaches, as well as being applied to bleeding gums.

The root bark is said to be an effective treatment against fever in cattle, and diarrhoea in calves, and the root itself is said to help improve spleen and liver ailments.

In the Garden:

As it does not have an aggressive root system, the blue butterfly bush is perfect for gardens large or small, and has been cultivated in botanical gardens for almost 100 years. Because blue is an unusual colour for the tropics, it is prized by collectors and considered to be one of the finest blue flowered subtropical plants. It can be pruned to keep it almost any size and is a great candidate for pot culture. Because it grows really quickly, and the flowers are produced in abundance throughout summer and well into autumn, the butterfly bush ideal for small or townhouse gardens, as well as patio planting.

Planted gregariously, the plant looks wonderful in a flowerbed or mixed shrub border, but looks just as lovely when planted as a single specimen. It can also be trimmed to make a sturdy border or screen, and can even be trained as a climber if given support. All this, plus the plants great insect repellent qualities – what more can a gardener ask for!

Cultivation/Propagation:

The butterfly bush grows best in warm, moist, frost-free regions, thriving in the Lowveld and along the KwaZulu-Natal coast. It is not suitable for very dry regions, but if it is watered well during dry periods, will do well in East London, and can be grown successfully in the southern and south-western Cape.

The plant will tolerate much colder conditions than most tropical plants, as long as it is planted in a warm protected position in the garden and the roots are thickly mulched in winter. Usually it is sold as hardy to a minimum of 3°C, but the plant has been known to survive short spells of temperatures as low as -1° and even -5°C outdoors. Always remember, young and unestablished plants are more vulnerable and should always be sheltered from extreme cold and wind.

In cold regions it is deciduous and may even be frozen right back to ground level, but will usually return in spring if the roots are mulched. It makes a wonderful conservatory plant and is often grown in a pot which can be moved indoors in winter.

The butterfly bush is not fussy and will grow in full sun, shade or semi-shade. Partial shade is recommended in areas where summers are very hot. It thrives in organically rich, well-drained soils and should be fed regularly with a fertiliser like 3:1:5. Although established specimens can withstand considerable periods of drought if need be, regular applications of water will keep you plants looking at their best. Reduce watering in winter, especially in cold regions.
 
Pruning can be done at any time to keep the plant in shape, and if it is grown in containers it can be clipped to maintain a rounded shrub. Cutting the old wood back to a pair of buds will improve flowering.

Propagation is by suckers, or semi-hardwood cuttings taken in summer, they root well in perlite. Seeds will usually germinate within 21 to 60 days, but even under good conditions germination may be erratic. Sow in spring or summer at a depth of +-3mm, in a well-drained seed sowing mix; the ideal soil germination temperature is about 22°C.

Caution: In tropical regions, blue butterfly bush is an aggressive plant that tends to spread and may become invasive, so be vigilant about removing any suckers that pop up out of bounds if you don’t want a small forest.

Problems, Pests & Diseases:

The pungent leaves and twigs seem to repel most insects, and this plant is not easily affected by most plant diseases or pests.

Warning:

Some parts of the tree have been recorded as being toxic if ingested, and care should be taken when small children are near.

The information contained within this website is for educational purposes only, recording the traditional uses of specific plants as recorded through history. Always seek advice from a medical practitioner before starting a home treatment programme.