Shrub-like Begonia are just as tough and incredibly long flowering as the cane-stemmed sorts. They bloom profusely from October onwards, all through summer and autumn, even into winter in mild suburbs. Some flower literally all year. They seem to be at their very peak around March. They are drought- and heat-tolerant, bloom well in semi-shade and can all be grown in pots as well as in the garden. They are excellent for flower arrangements, lasting for ages in a vase. There are over 300 species and cultivars grown in gardens today. Most of the species originated in Central and Southern America and seem perfectly suited to Sydney's climate.
They have a greater diversity than the cane types. Growth habits vary from the low-growing, delightfully lime-striped Begonia listada (ht 25 cm) to the statuesque Begonia luxurians (ht 1.5 m to 2.5 m) with its slim, long-fingered leaves and lacy white flowers; many are around the 1 m mark in height. Leaves range from being small, glossy and ) to ones which are huge and hairy, and textured with deeply cut veins as in Begonia scharffii (or more correctly Begonia scharffiana?) (ht 1.2 m). Some have leaves which are beautifully marked with silver and purplish-green, such as 'Little Brother Montgomery'; the foliage of Begonia metallica (ht 1.2 m) has a lustrous sheen that brings light into shaded areas of the garden. 'Island Gem' is a vigorous form and can cope with a fair bit of sun: in sun its flowers are pink, whereas they are white if it is grown in shade.
The waxy flowers are held in thick clusters, and are usually white or pink. Begonia 'Nellie Bly' (ht 1 m) is a particularly lovely pale pink and white cultivar. There are some brilliant red blooms, such as those of Begonia fuchsioides 'Red Cascade' (ht 1m or more), the so-called 'fuchsia begonia', which has amazingly shiny pendulous blooms reminiscent of species Fuchsia.
The shrub-like Begonia are natural partners for Plectranthus and Camellia sasanqua, which also thrive in shade and are so stunning in autumn; they also look good growing with Justicia, Hydrangea and Japanese windflowers. Shade-tolerant strappy leaves such as those of giant Liriope or Iris japonica provide a contrast of foliage. The pink or white freckled leaves of the polka-dot plant (Hypoestes phyllostachya) can be paired with shrub-like Begonia blooms of the same hue as their spots.
I generally prune the plants back a bit to shape them in late winter (late August) then feed them with a general-purpose fertiliser. They can be cut back a bit harder if they have become leggy, but should not be pruned severely. Tip pruning of young plants will promote a compact shape. They generally will do well in ordinary garden soil with some compost dug in, and they don't like too much water (although Begonia foliosa is said to be an exception to this). They enjoy an application of mulch and some liquid fertiliser occasionally during the growing season. They are easily propagated from cuttings taken in spring or autumn. It is best to replace the plants after about five years and start again with a freshly propagated specimen. They are frost sensitive but will survive through winter in most Sydney suburbs. If they do get burnt by frost, don't cut off the afflicted foliage until late winter. Plants grown in pots should not be overwatered: apply water only when the surface of the soil is dry. Perlite added to the potting mix will keep the mix open and well drained.
The Royal Botanic Gardens in Sydney have several large, beautifully maintained Begonia beds, and plants are propagated from these specimens for sale year-round in the Friends' nursery. Plants can also be obtained at Begonia shows, usually held in late summer.
For more information, visit the very informative website of the NSW Begonia Society.
Flowers in January, February, March, April, May, December.