Melianthus

///Melianthus
Melianthus 2014-03-03T16:54:16+00:00

Fifty years ago the Royal Horticultural Society suggested that Melianthus major was only suitable for sub-tropical bedding schemes in Cornwall.  Twenty five years ago garden-writer Graham Stuart  Thomas advised it could be grown only in the warmest counties. This year you can find it in garden centres throughout the country. I saw huge dramatic clumps of the plant flowering in suburban Hertfordshire last week and in my own garden another species, Melianthus comosus, has been flowering since May.

Alterations in the weather may well be responsible for this change in the plant’s popularity.  As significant, though, is our increasing adventurousness as gardeners, and the modern taste for an exotic look in our gardens.  Melianthus major grows very rapidly and even within one season can reach seven feet tall.  This lush growth, coupled with  its large, glaucous leaves, have made it as fashionable as cannas, bananas and tree ferns with those trying to evoke the jungle in their back gardens.

More suited to British gardens and to gentler planting schemes is Melianthus comosus.  This is a much smaller evergreen shrub with a compact rounded shape that sits well in traditional borders.  The small olive grey leaves have the same serrated edges and pleated centres as their bolder cousin, but a gentle breeze reveals attractive coppery-gold undersides.

From late spring bright red flowers cluster like flocks of finches at the base of the leaves.  In the wild the flowers are pollinated by birds, attracted by the huge quantity of nectar in each of the little flowers.  So much nectar is produced that it overflows, dribbles down the stems and splashes the foliage.  Be careful though, because, sweet as the nectar is, it will stain your hands and clothes.  I don’t know what the pollinator is here in Britain but there are always lots of seed pods; as attractive as the flowers, these are inflated cubes which dangle like Chinese lanterns throughout the summer.

The six species of Melianthus are indigenous to South Africa, where their common name translates as ‘Don’t-Touch-Me-Bush’.   This refers to the smell of the foliage, which some people find unpleasant.  If the leaves are crushed the odour is certainly strong but not, to my nose at least, unpleasant.  M comosus  grows mainly in the dry interior of the country but M. major is much more widespread and runs along ditches and roadsides.  This tendency to colonise areas by runners has made it an unwelcome weed in parts of Australia and New Zealand.  If the trend for ‘jungle’ gardens continues it could well become that it Britain.

How to grow

The primary requirements for growing Melianthus are a rich, well-drained soil and an open, sunny position.  The lax, sappy growth of Melianthus major is usually hit by frosts during the winter, The dead leaves and stems can be left to protect the crown of the plant from further cold damage.  I prefer to clear them away as soon as they are blackened by frost and cover the crown with a dry mulch.  This prevents any disease in the rotting foliage spreading to the new shoots in spring.  The stems of plants that do come through the winter unscathed often look scraggy and should be cut out to encourage new shoots.  The tall arching sprays of chocolate brown flowers are produced at the top of the previous season stems, so if you want flowers leave some of the stems in place.

Melianthus comosus is much better at withstanding the rigours of British winters.  All that is required in spring is to clean away any dead leaves and prune any stems that spoil the shrub’s shape.  After a few year the base of the stems become bare and woody.  They can be cut back to the ground to encourage new growth from the base.

Both plants can be propagated by taking basal cuttings in the spring, but the easiest way to get plants is from seed.  Sow the shiny black seeds, lightly covered with a layer of vermiculite or horticultural grit, in spring and they will germinate within a couple of weeks.  A month later the plants will be large enough to pot on or plant out.  Snails are partial to the new shoots and whitefly are attracted to plants grown in greenhouses, but in general Melianthus are sturdy plants that are not prone to disease.