Posted on | July 5, 2008 | 2 Comments
Fancy growing something different in the garden this year? How about hardy begonias? Now there’s a thought! Begonias are in a genus of about 900 species of perennials, shrubs and climbers. It is a very diverse family of plants which can be fibrous rooted like the well-known bedding plant Begonia semperflorens with its blowsy flowers or it can be tuberous rooted and, as such, features those ever-popular types with their enormous waxy, almost plastic-looking blooms. Then there are those which are grown for their foliage, like the showy-leaved Begonia Rex, that line the shelves in the house plant section of garden centres along with the tall cane varieties often with splotches and dots. Luckily for lovers of this handsome family of plants, there are several that are hardy enough to survive most winters in the warmer parts of our Norfolk gardens.
The best known hardy begonia is Begonia grandis ssp. Evansiana. This delightful begonia is tuberous rooted, from which red branched stems emerge, from mid to late spring according to weather conditions, rapidly growing up to 50cm (20in), with a 30cm (12in) spread, by mid-summer. The broad fleshy leaves are pale green above and flushed red with prominent veining underneath on red leaf stalks.
The pink 1.5-2.5cm (½-1in) flowers are produced from the leaf axils in nodding clusters from mid-summer on. The flowers and leaves look especially attractive in the evening when the sun shines through.
Not quite so common but equally attractive is Begonia Grandis Subsp. Evansiana Var. Alba, an attractive white-flowered form. In the autumn when the leaves start to turn yellow, small bulbils are formed in the leaf axils which fall to the ground, thus forming new plants and creating a colony in only a few years.
Several hardy forms have been discovered in recent years by Bleddyn and Sue Wynn-Jones, of Crûg Farm Plants in North Wales, on their plant-hunting expeditions in Taiwan and other parts of Asia.
One in particular – Begonia grandis ‘Sapporo’ – is a very hardy form of this species from Sapporo, capital city of Hokkaido on Japan’s north island, where the winters can be severe. This gem grows to a height of about 90cm (35½in) in its native habitat, on erect stems that are red at the nodes, which in turn produce bulbils in the leaf axils in autumn. It is very distinctive in foliage and form, with large, palmate, dark green leaves which are dark red underneath. The pink flowers are borne in terminal sprays, opening from reddish buds in late summer to first frost.
Begonia grandis ssp. evansiana ‘Pink Parasol’ was also collected by Bleddyn and Sue from Shikoku, Japan, where it grows to a height of 90cm (35½in), with luxurious palmate leaves. It bears sprays of pink flowers, opening from reddish buds in summer from mid-summer to first-frost. It also produces bulbils – or as they should be more correctly called advantageous tubers – which form in all its joints, falling to the ground and rooting by the following spring in its natural habitat. Hence, this should be an excellent colonising plant for a damp and shady corner of the garden. All in all, a very promising hardy begonia.
Begonia palmata is another hardy begonia collected as a dormant rhizome from the Lachung valley in north-east Sikkim, where it is locally hardy to -9C (16F). It grows to a height of 60cm (23½in). The very large, deeply lobed, fleshy leaves can grow up to 40cm (15¾in) long, on darkly mottled stems. This monster bears pink flowers from mid-summer to first frost and prefers moisture-retentive, well-drained soil in warm dappled shade. Begonia Ravenii, a species of this mostly tender genus, which was collected at high altitude in the mountains of Taiwan, is reportedly hardy to -9C (16F).
It grows to a height of 90cm (35½in) from deep rhizomes and has large, ovate, almost succulent leaves to 30cm (1ft) long. From early summer to first frost, it has pink flowers and prefers shade and moisture-retentive soil that doesn’t get too wet.
Although only hardy in the warmest gardens, Begonia sutherlandii is always popular at the Exotic Garden as a container plant that is overwintered frost free. This beauty is a dense, many branched, clump-forming, tuberous begonia, growing to a height and spread of 46cm (18in), with bright green, slightly toothed, lance-shaped leaves up to 15cm (6in) long, often with red veining.
Throughout the summer, panicles of pendant orange flowers, up to 2.5cm (1in) across, are freely produced. This delightful begonia also produces bulbils in the leaf axils, which should be collected for growing the following year. It makes an excellent container or hanging basket plant. I find it’s rather prone to powdery mildew – greyish white patches forming on the leaves. If untreated the whole plant becomes rather unsightly, so prompt action should be taken by spraying with a suitable fungicide.
If on the other hand you feel like being rather brash with your planting – something I always enjoy – then try planting out some of the more tender species and varieties for the summer. A drift of Begonia rex in a moist shady corner will always turn an eye.
Many of the more unusual houseplant types can be kept in containers and grouped together in varying sizes to create a tropical looking setting. Just remember to keep them out of the sun and moist at all times.
Now’s the time to pull Begonias out of the doldrums. As Christopher Lloyd memorably put it: “If I was reduced to growing only one genus, Begonias would be it.”
The Exotic Garden is open every Sunday afternoon (1-5pm) until the end of October and at other times by appointment (tel 01603 623167). Entrance is £4.50, children free. For more information visit www.exoticgarden.com The entrance to the Exotic Garden is to the left of the Alan Boswell Insurance building at 126 Thorpe Road, Norwich NR1 1UL.