Tuberous begonias
Tuberous begonias are gorgeous plants that can lead you headlong into a new plant passion, as JENNIFER STACKHOUSE discovered
One autumn, while visiting a couple of tuberous begonia growers in Burnie in northwest Tasmania, I became smitten with the big blousy blooms. Several pots and a hanging basket just had to come home, where they decorated the house and front porch for months, and made repeated appearances on Facebook. They’ve continued to delight each summer and autumn since.
Owen and Julie Bedford have been growing begonias for more than 20 years. The colourful plants festoon their house, hanging under the verandah, across the front of the garage and in a space that once housed the barbecue. As well, they have a shadehouse dedicated to begonias. They open their garden to special-interest groups, and I heartily recommend a visit.
The tuberous begonias grown today have been developed with some 100 years of breeding, using a mix of begonia species from Central America. They grow from a large, flat tuber. In late spring, brittle shoots appear, and these grow to produce stems of large, double, rose-like flowers that come in a range of fluorescent tones of pink, orange, yellow, apricot, red or white. Some have bicolour flowers, while others have petals with frilled or picotee edges. The flowers can be 10cm across, and plants can be upright or trailing.
These beautiful plants are usually seen in the collections of specialist growers or in glasshouse displays. I had always admired them but preferred to grow the less showy and less demanding cane begonias, or the bright and easy-going bedding begonias, before my trip to Burnie.
a tale of two kitties
As well as being swept up in the desire to enjoy these bold blooms at home, my interest in tuberous begonias was piqued by my cats. Keep reading – there is a link!
Several years ago, I found two fiveweek-old kittens (one orange, one tabby) tucked into the nesting box in my chook shed. I scooped them up, took them inside out of the cold and, of course, ended up keeping them. After asking around the neighbourhood, I discovered the kittens were the offspring of a small feral cat that had given birth to them in my neighbour Kath’s begonia glasshouse.
Kath had retired from growing begonias and the glasshouse was empty but she provided the mother cat with food and milk and played with the kittens, which is why they were so tame by the time they ended up at my place.
When I saw a large tangerine-orange begonia for sale in Burnie, the colour reminded me of the orange kitten at home, so I just had to have it. I also felt it was time we had more begonias in the neighbourhood.
care & maintenance
Tuberous begonias grow best where summer temperatures are mild and humidity is low. Ideal growing areas include Tasmania, elevated and mountain regions in Queensland, New South Wales and across Victoria. They grow with difficulty in the south of Western Australia and in cooler positions in the Adelaide Hills.
Potted plants in flower are available in summer and autumn from specialist growers, at plant shows held by specialist begonia groups, and from leading garden centres. You can also buy tubers from mail-order bulb suppliers in winter.
These plants need special care, so bringing them home – much like stray kittens – shouldn’t be taken lightly. They need filtered light or semi-shade and don’t like temperatures too hot or too cold. They die down over winter, when the tubers are usually lifted from their potting mix and stored dry in a pot or foam box, and need to be kept in a cool place that is protected from the extremes of winter cold.
The nurturing starts in earnest when growth resumes in spring. Pot them up into a pot (or a hanging basket if you are growing a trailing variety) using a very free-draining potting mix with added perlite or gravel and slow-release fertiliser. Place the flat tubers, hollow side up, on the potting mix and cover with another 2–3cm of mix. Protect from late frost, but position them where the plants receive some morning or dappled light.
After re-potting, you need to encourage the plants to grow. At this stage, careful watering and good drainage are paramount.
Owen warned me that many begonias die from overwatering or poor drainage. To avoid losing your plants, allow the potting mix to dry out between watering, especially as they are resuming growth. Also, protect the young shoots from snails and slugs (use iron-based snail pellets that don’t harm pets or wildlife).
Begonias flower in mid to late summer and continue well into autumn, provided summer temperatures are cool. Increase watering when the plants are in flower but avoid wetting the blooms or leaves. Remove spent flowers and leaves regularly.
From late autumn on, reduce watering so the plants can die down and resume winter dormancy. As they die down, flowering stops, leaves yellow and the plants shed their brittle stems. The tubers can then be lifted and stored or allowed to remain unwatered in their pots until next spring.