Aeschynanthus buxifolius

A surprisingly hardy plant from southeast Asia.

Aeschynanthus: tropical ‘lipstick plants’

A number of years ago I worked in the Southeast Asia section at Kew Gardens, and took part in several field trips to Borneo.

In 1848, the Victorian colonial administrator and naturalist Hugh Low said of the flowers of Borneo “the woods abound in shrubs and flowers, which delight the eye and attract curiosity by their rich and gaudy colours, or their delicate and beautiful forms”. One particular climbing plant he said, “yields to none in beauty”. That plant was Aeschynanthus, and having seen it myself growing in Borneo, it soon became one of my favourite southeast Asian plants, and high on my wish-list of plants to grow at home.

Aeschynanthus tricolor growing in a forest clearing in Sabah, Borneo, 2006.
Aeschynanthus tricolor growing in a forest clearing in Sabah, Borneo, 2006.

The genus, which contains around 160 species, is distributed throughout Indochina and Southeast Asia. All species are epiphytic, that is they roots not in the ground but up in the trees, their stems trailing along mossy branches, rooting and branching at nodes, or arching and trailing from tree limbs. They bear large bright red flowers in clusters near the tips of stems.

For me, their bright, showy flowers, neatly arranged glossy leaves and pendulous habit epitomise the beauty of tropical flowers.

Aeschynanthus tricolor

Low (after whom the summit of Mt Kinabalu in Borneo would later be named) first visited Borneo in 1845 to 1847, collecting plants for his father’s London plant nursery. One of the plants he returned with was Aeschynanthus speciosus, which makes a spectacular house plant, although Aeschynanthus pulcher and various hybrids and cultivars are more commonly seen for sale.

They are also known as lipstick plants, due to the scarlet flowers and the way the bud emerges from the cup-shaped calyx in some species, like an opening lipstick.

Aeschynanthus is a member of the mainly tropical Gesneriaceae family, which also provides some other popular flowering houseplants, such as Saintpaulia (African violets) and Streptocarpus (Cape primroses). Dibley’s plant nursery specialises in house plants of this genus.

Aeschynanthus speciosus.
Aeschynanthus speciosus. Photo: C T Johansson (Wikimedia Commons, CC by 3.0).

A hardy species of Aeschynanthus?

I had assumed therefore that Aeschynanthus could only be grown as houseplants in the UK, to be taken outside over the summer months perhaps, but certainly nowhere near hardy enough to be permanently planted outside. That is, until I read about a vertical garden installation in Paris by the botanist and horticulturalist Patrick Blanc, famous for his living walls which can be found all over the world. As well as being spectacular pieces of urban horticultural, Patrick’s knowledge of plants means that his living walls are often full of very interesting and surprising species.

Aeschynanthus buxifolius growing in the L'Oasis d'Aboukir living wall in Paris.
Aeschynanthus buxifolius growing in the L’Oasis d’Aboukir living wall in Paris, 2014. Photographs © Patrick Blanc.

I was amazed to read that Patrick’s 2013 permanent outdoor installation at L’Oasis d’Aboukir in Paris contained a species of Aeschynanthus thought to be hardy to at least -3°C. The plant in question was Aeschynanthus buxifolius.

An article in Curtis’s Botanical Magazine revealed that the species was described in 1903, and has so far been collected in southern China and northern Vietnam. Some mountainous areas in the region, such as the Hoang Lien mountains in northern Vietnam, can experience sub-zero temperatures and have produced some surprisingly hardy plants in recent years. Excitingly, the article stated that a plant collected by Keith Rushford at an altitude of more than 2,000m in northern Vietnam in 2003 had subsequently proved able to withstand some frost, surviving -6°C in a sheltered position in 2008/2009.

Flowers of Aeschynanthus buxifolius
Flowers of Aeschynanthus buxifolius. The calyx is green faintly flushed red, with linear or narrowly triangular lobes to 8mm x 1.8mm. The corolla tube is bright red externally, with cream and dark markings on the lower three lobes. Stamens are long and exerted, fused in two pairs.
Flowers of Aeschynanthus buxifolius.
Leaves are small, opposite, rounded and slightly fleshy.

I obtained several plants in 2016, and planted them outside, some in a raised bed in a shaded and sheltered position near the house, and some in a more open, sunny position out in the garden. The name buxifolius means “box-leaved”, on account of the rounded, glossy leaves looking like boxwood, so I thought it would be fun to try using some plants to plug some gaps in the box hedging. I can report that all our plants have sailed through the past two winters, including the Beast from the East (minimum temperature -6°C), without any protection, remaining evergreen throughout and flowering reliably the following autumn.

Flowers of Aeschynanthus buxifolius growing in our garden.

Flowers of Aeschynanthus buxifolius growing in our garden.
Aeschynanthus buxifolius growing in our garden in moist but free-draining soil in a shady raised bed near the house.
Aeschynanthus buxifolius as an alternative to box hedging (Buxus sempervirens).
Planted in a gap in the hedging, Aeschynanthus buxifolius makes a surprisingly good flowering substitute for dwarf box.

I am very excited to have found this plant, which brings memories of the southeast Asian rainforest to our garden, and look forward to discovering more hardy “tropical” plants in the future.

Aeschynanthus buxifolius growing in our garden.

 

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