Hoya imperialis – Why you should remember to look up when you visit the glasshouses

Hoya imperialis inflorescence

Hoya imperialis inflorescence

If you follow the paths through the glasshouses until you can go no further then look up, you will see thick, green stems many meters long, and flowers hanging in stiff clusters like an open umbrella. They have smooth, shiny, deep pink-red petals and creamy white stamens. The name of this plant of substance is Hoya imperialis. The genus Hoya is given the common name ‘wax flower’, and with a glance at the polished petals you see why it has earned this name. They can last for several weeks, are impervious to any munching animals and have evolved to withstand the tropical rain storms experienced in its native Borneo and Malaysia.

This year, this plant in the Tropical Montane House, has more flower heads than ever before. Louise Galloway, Glasshouse Supervisor, believes it is because of the way it has been trained and tied in to the supports. She now uses methods she saw growers in Borneo using to train the plants here at Edinburgh. First, the plant is trained vertically up a pole to a height of two to three metres, and then it is tied in to grow horizontally along a framework. As soon as it starts to grow on the horizontal, flower buds are produced. This is because the plant ‘thinks’ – we know that plants don’t have brains, but they do react to the conditions in which they grow – it has reached the top of the tree it would naturally climb up, and begins to flower where high light levels and pollinators are available

Flower of Hoya imperialis

Flower of Hoya imperialis

Once you have found the plant and seen the flowers, follow the stems back to discover where it is planted. Compare the number of flowers and size of the plant to the size of pot in which it is growing!

← Previous post

Next post →


  1. Rob Jones

    Saw the Hoya imperialis in bloom for the first time today – stunning! In fact, the furthest end of the montane greenhouses had three ‘purple beauties’ in bloom at the same time: the Hoya, a Vanilla plant and a Passion Vine. Sadly, I could not get them all in shot at the same time.

  2. Amina Ashe

    Can you sell Hoya imperialis

    • Site Editor

      Although we do have an annual plant sale for some specific material generally we do not pass on material other than for academic study. Wild collected materials is governed by agreements with the countries from which they were collected mainly now the Nagoya Protocol.