Plant Spotlight – Begonia rex

We’ve made good use of the recent closed period and given the Carnivorous Plant House a mini-makeover ready for re-opening. Glasshouse Area Supervisor, Abby, has been busy filling the lower benches beneath our brilliant pitcher plant display with shade-loving tropicals like bromeliads, Tradescantia and begonias.

All of the new big, leafy plants look great together bursting out of their pots and creating a bold, tropical effect for the summer. But there’s one plant that really stands out and makes an impact – perhaps the boldest of them all – Begonia rex.

Otherwise known as the king begonia, Begonia rex really is king when it comes to creating a tropical effect. There are hundreds of different kinds of king begonia hybrids, all grown for their colourful foliage and bold leaf shape.

This year we’ve chosen to grow B. ‘Savannah Pink Parfait’, B. ‘Silver King’ and B. ‘Vesuvius’ as part of our new display. B. ‘Savannah Pink Parfait’ is the most colourful with jaunty, ovate shaped leaves with a deep, plum-purple centre and bright pink mid-section, all crimped around the edges with green and purple again.

1. B. ‘Silver King’ is more subdued but no less striking for it. It has the same purple crimped edge but instead, for the most part, is mottled khaki-green and silver-grey inside. B. ‘Vesuvius’ has the darkest colouring of the three, almost entirely purple, and nearly black around the veining that dissects the leaf throughout.

Begonia rex are evergreen, tuberous begonias meaning that they grow from a thick, fleshy, modified stem that is usually underground, or just partly exposed above the soil. A native of India, they prefer much higher levels of humidity than many other species of begonia. Those grown in dry air will brown and crack at the edges of the leaf ruining their effect.

Otherwise, they should be grown in partial-shade, or at least indirect light, such as in an east-facing window. Too much sun will scorch and bleach the leaves. Tuberous begonias should be watered sparingly to avoid root rot. Their succulent stems store lots of water meaning they are relatively drought tolerant, so allow the surface of the soil to dry out between watering each time.

They make excellent houseplants and enjoy growing in average room temperatures through the summer. As long as temperatures are consistently above 13 degrees Celsius (and they are given protection from bright sunshine) they can even be grown outdoors through the summer months. However, they cannot remain outdoors once temperatures fall – they must be in a totally frost-free environment by the winter or they will freeze.

Most begonias are really easy to propagate from leaf cuttings which for Begonia rex should be taken in May or June. First, select a just matured leaf and remove the stalk. Then carefully cut the leaf into sections about 1-inch square, making sure you cut across the leaf through the major veins. Lay the sections right-side-up on a seed tray filled with free-draining compost. You may have to peg the leaf cuttings down to get good contact with the soil. Place the tray somewhere warm, light and humid (a heated propagator would be ideal) and little plantlets will soon form around the edges of your cutting.

Few plants can be beaten for impact when it comes to foliage alone. Begonia rex look brilliant grown as individual specimens or paired with other tempting tropicals like we have done in the Carnivorous Plant House. Why not try creating your own tropical-looking display at home? Try pairing them with other readily available, staple houseplants, like tender ferns such as Nephrolepis, big hearted Philodendron and colourful flowering African violets.