Begonias Growing the Rex – Seeds and Leaves

Part I on Rex Begonias

Seeds Are Tiny

Rex begonias are easily grown from seeds. A small clear plastic seed tray with good drainage and damp screened sphagnum moss pressed down firmly is ideal for seed sowing. Rex seeds are so tiny they appear to be rust colored dust, and it is a miracle when they sprout so readily in about ten days. Sprinkle the seeds thinly over the damp moss and do not cover them. Place the top on the tray and set in a warm, dark place to germinate.

Bottom heat will speed germination. After the little specks of green begin to appear, gradually remove the top of the seed tray and bring the plants into more light. When the seedlings have four to six leaves, transplant to a flat of leaf mold and sand. Transplant the seedlings two inches apart, being careful not to damage the small roots when separating them. They may be left in the flat and fed every two weeks with liquid food until they are three or four inches high and ready for three-inch pots. This will take three to four months.

New varieties and different leaf patterns result when two different rex begonias are crossed. After you have become a proficient grower of rex begonias, you will want to try your hand at cross pollinating. This is easily done on a bright, sunny morning when the pollen is ripe, and when the yellow, twisted pistil becomes slightly moist with a sticky substance and is ready to receive the pollen. When the seed pod begins to turn brown, it is ripe and ready to be picked. Put it in an open envelope or dish until it is completely dry and the seeds are ready to be tapped out of the papery seed pod.

The leaves of rex begonias will root and produce more plants exactly like the one from which the leaf has been taken. Use mature, vigorous leaves from a healthy plant, leaving the leaf’s stem intact. On the underside of the leaf, at the junction of the veins, cut through the veins just below the lateral (V-shape) but do not cut clear through the leaf as this will cause it to rot. Be sure to use a sharp knife that will not bruise the leaf. Place this leaf in a jar, propagating case or plastic box that is filled with two inches of damp leaf mold, sand and peat moss or vermiculite, with the back of the leaf down. Pin the leaf down with toothpicks, or hold in place with pebbles. Do not cover the leaf with the rooting medium, but cover the stem a quarter of an inch. Keep moist, not wet, and place in a warm, shaded place. It will take from two to three months for roots and subsequently new plants to form.They are then divided and treated like young seedlings.

Propagation is possible from leaf wedge cuttings. Trim mature leaves to three inches and cut between the large veins. Be careful to include a small portion of the main stem with each wedge. Dip the wedge in a rooting hormone, and set 1/4-inch deep at an angle in the rooting medium. Small plants grow from the bottom of the wedge. Three to five wedges may be made from one large leaf.

Rex Culture

Culture of rex begonias differs slightly from that of more commonly grown begonias. Rexes will not tolerate wind or hot sun, and they do not like wet feet. They must have free air circulation. They are heavy feeders and can be grown outdoors in the summer in shade if sprayed twice a day. They will grow indoors in the greenhouse the year round, or in your living room – if enough humidity can be made available. A glass or plastic case is a great aid in growing rex begonias in the house. Or they may be set on a tray of moist sand or gravel.

If you have a table in a dark corner that could have a fluorescent light unit placed over it, an ideal place should result for your rex begonias; they can also be grown in pots using the double pot method. Line the large pot with damp sphagmum moss and set the small pot with your rex inside. Keep the moss damp and the roots of your plant will not dry out.

Upright rexes may be grown like ordinary cane or angel wing begonias, but they require the same warm, humid conditions that regular rexes must have. Use bamboo cane stakes to keep the uprights in presentable condition. Tie the branches loosely to the stakes with soft yarn, or use soft twistem wire for this tying. Place the stakes and ties so they will not show from the outside, thus giving the plant a graceful, natural appearance.

Prune the plants in spring before new growth starts, leaving two nodes or leaves on each branch. This will give a compact plant with fresh, new growth.

Hundreds of different named variety rex begonias are available from commercial growers. A box of a dozen assorted, unnamed seedlings from a hybridizer can be had inexpensively. Their leaf colorations will be different and exciting. It is wise to start with less expensive varieties. They are usually the easiest to grow, and when you become a successful grower, you can try those plants that are more difficult.

by E Dillard

Related Articles Of Interest:

• Growing Wax Begonias from Seed
• Rex Begonias Showiest of The Foliage Plants
• Begonia Facts – Tuberous Begonias are Not Impossible
• Try Growing Tuberous Begonias – Part II