4 October 2016

Exotic blooms for winter gloom

Jack Clutterbuck describes flowers of the mallow family, known botanically as Malvaceae, which grow in the Tropical Nursery at Kew.

By Jack Clutterbuck

A touch of the exotic 

As the last colours fall from the trees under our grey skies, and we brace ourselves for the winter ahead, a touch of exotica is required to escape the gloom. Here in the Tropical Nursery at Kew, a whole array of far-flung wonders of the plant kingdom are cared for, and nothing suggests the spirit of the exotic like the flowers of the mallow family, known botanically as Malvaceae. 

The Malvaceae family 

Found in temperate and tropical regions of the world, these delightful plants can be easily recognised by their often brightly-coloured, funnel-shaped flowers, with 5 separate petals and distinctive protruding stamens surrounding the pistil. 

A widely grown member of the mallow family is the hollyhock, often found leaping waywardly from flowerbeds in the height of summer, but here in the Tropical Nursery we have the riches of warmth all year round to grow some of the 3,700 species of Malvaceae that occur worldwide. 

Malvaviscus arboreus 

Seen here are the stunning scarlet flowers of Malvaviscus arboreus. Known as the sleeping hibiscus due to the petals remaining closed, this adaptation allows the flowers to be pollinated only by hummingbirds and butterflies that are able to hover as they feed, unlike other pollinators that require a landing pad. They move from one plant to the next, drawn in by flashes of red amongst the canopy. This sleepy adaptation encourages more precise and successful pollination. 

Found growing in subtropical areas of southern Texas and Florida, as well as the cloud forests of Mexico and Colombia, this plant will be one of the floral delights in Kew’s Temperate House when it opens once again. 

Many plants of the mallow family are grown in the temperate zones of the Tropical Nursery, some finding a home here while the Temperate House is restored to its former glory, and some on a more permanent basis due to being endangered or even extinct in the wild.  

Trochetiopsis ebenus 

The elegant white petals and musky purple stamens of Trochetiopsis ebenus are a joy to see right now, but for over a century this member of the mallow family was thought to be extinct. 

Endemic to the remote island of St Helena in the Atlantic Ocean, this glorious shrub had a close shave with vanishing from those distant shores forever. Sailors and explores would draw up on St Helena to rest their sea legs, leaving goats on the island to feast upon their return. Having not evolved to withstand the constant nibbling of these rotten goats, the vast hillsides of Trochetiopsis ebenus were diminished, and by the mid-19th century were thought to be extinct. 

However, by sheer determination, two plants were found clinging on a cliff face in the 1980s. Heroic efforts were made by a local to collect cuttings, which were then sent back to the UK and grown on in botanic gardens including Kew. Kew is now involved with efforts to re-introduce this valiant species back to its rightful place. 



Hibiscadelphus is a genus in the mallow family endemic to the land of all tropical dreams, Hawaii. The flowers of this genus are of a curious nature. Hiding beneath lush green leaves their subtly coloured petals remain wrapped up while the stamen and pistil explode outwardly. Of the seven species described, four are now thought to be extinct. A further two more are extinct in the wild but persist in cultivation, one of those being H.hualalaiensis, seen below. 

The only species known to still have wild populations is H. distans, with around 20 wild trees and 150 re-introduced specimens. The serious decline of this genus is thought to have coincided with the arrival of the Polynesian rat (feeds upon seeds) that came with early Hawaiian settlers.

Where to see them 

While some of these temperate mallows reside here in the nursery during the Temperate House restoration, many can still be found growing in the Princess of Wales Conservatory at Kew, as can many of their tropical relations. Failing that, go and buy yourself a pack of hollyhock seeds today to grow your own exotic blooms for next year!