The Begonia Rex Cultorum Group includes hybrid varieties obtained by crossing royal begonias with other species and varieties of begonias.
Begonia royal (Begonia rex) was discovered in the Indian state of Assam, and introduced into culture in the middle of the 19th century. This is a herbaceous bushy plant with a lodging, pubescent, shortened stem. Leaves are asymmetric, heart-shaped, up to 30 cm long and 20 cm wide, greenish-brown above, with a wide silvery stripe. The petioles are pubescent, up to 10-20 cm long. Small white-pink flowers are collected in racemose inflorescences.
The rex group of begonias was first mentioned in print by the American botanist and gardener L.N. Bailey in 1920. By crossing the royal begonias with other species, a wide palette of color combinations in leaf color has been achieved. The first hybrids were obtained with other Asian species such as yellow begonia (B. xanthine), Griffith's begonia (B. griffithiana) and hatakoa begonia, or red-nervous (B. hatacoa syn. B. rubro-venia)... When crossed with tuberous begonia, large (B. grandis) more hardy varieties with a vertical form of growth were bred. Introduction of genes for imperial begonia (B. imperialis) yielded varieties with smaller leaves. Crossing with caudex begonias (semi-tuberous) made it possible to obtain miniature varieties of the Rex group. The red metallic sheen of the leaves, which is closely associated with Rex begonias, was introduced by crossing with Begonia decora.
Now many varieties have been bred with a varied shape and color of leaves, from almost red to silver, with stripes, veins and spots contrasting in color, with a warty or corrugated surface, from medium-sized to more than 40 cm in diameter. Their beauty really lives up to the name Royal begonias. Like all begonias, they can bloom, but flowering is clearly inferior to the beauty of the leaves. Most royal begonias have a creeping rhizome, but there are also vertically growing varieties, so they are placed in a group separate from rhizome begonias. Plants of the Dutch breeding series Magic Colors, Amazing and others with incredibly beautiful leaves of various colors and shapes are often supplied to our stores.
- Merry christmas - one of the most beautiful varieties found on the market. Plant height 30-50 cm, diameter up to 40 cm. Leaves are medium, asymmetric-ovate, pointed at the tips, with a slightly wavy edge. The middle of the leaf is maroon, smoothly turning into a bright crimson color, which is abruptly replaced by a wide silvery stripe, turning into an emerald one with pearl specks, and along the edge of the leaf is trimmed with a burgundy border.
Curly merry christmas (syn. Merry christmas corkscrew) - from the previous variety, differs in the presence of a curl (snail) in the center of the leaf.
Growing conditions and breeding methods of royal begonias are similar to rhizomes, see. Features of growing rhizome begonias.