Home > Begonian > Volume 43 (February 1976, pages 485 - 488)

Training Plants in the Way They Should Go
by Elda Haring

While some begonias are naturally compact and low growing, many others need special handling to attain a symmetrical plant or to keep the plants from becoming lanky, sparsely foliaged and unattractive. If you start your training program with young plants obtained from a commercial grower or grown from your own cuttings, timely pinching, pruning and patience are the essentials to develop a compact plant. If, with an eye to flower show competition you have purchased or fall heir to a specimen-sized begonia, some judicious pinching or pruning will produce an attractive and show-worthy plant.

Pinch the growing tip at the end of new shoots to stop new growth and encourage branching. You will note in the photo of B. 'Marjorie Daw' a definite pointed tip. If left alone a new leaf unfurls from this tip and the plant continues its upward or outward growth. The new leaf may also be removed after it has unfurled if done carefully, for in many cases the flowers are produced at the tend of the branches or in the axils of the leaves and might inadvertently be removed. You will notice in the photo of B. 'Catalina' a new leaf being carefully removed leaving the flower buds intact. Pinching the ends of resultant new shoots and branches as they grow can be continued until the plant has reached the size and shape you want. The aim is for compact, bushy plants eventually covered with flowers.

B. 'Marjorie Daw'. Note pointed tip
	B. 'Catalina'.  Pinch new leaf behind flower.

If the tip is removed from cane begonias while still small, new stems will soon grow from the soil level. The growing tips of rhizomatous begonias can be pinched out to encourage compact growth. Removing the top inch of B. semperflorens will force side branches, delaying flowering only slightly. While some of the shrub-like and thick-stemmed begonias naturally grow in a compact fashion many of them need to be pinched while young and growing vigorously to keep them within bounds.

Pruning is practiced on old overgrown plants or those that have become ungainly and need shaping. In the case of begonias that have lost some or all of their lower leaves like that of B. serratipetala in the photo, cutting all branches off close to the pot level will cause the plant to send up new shoots. If these in turn have the soft growing tips pinched a well-shaped will result.  If you have a cane begonia that has developed only one stem and is much too tall for its pot, cut the cane to within 10 or 12 inches of the pot. This will cause the plant to send up new stems from the pot level to give you an attractive plant. Upright rhizomes or stems of shrub -like begonias can be pruned by cutting off protruding stems just above bushy growth to produce a more compact and shapely plant. B. manicata aureo-maculata shown in the photograph would have been much improved by the timely removal of the two uppermost stems.

B. serratipetala. Cut leggy growth to force new shoots.
	B. manicata aureo-maculata. Uneven growth can be avoided by early control.

To rejuvenate old plants it is not only possible but most important to take drastic action.  It will be necessary to cut back many of the mature stems as shown in the photo of B. 'Medora' to induce new growth. Remove with knife or scissors crowded shoots or any that have become hard and woody, and shorten the newer growth considerably to provide a suitable frame work for the rejuvenate plant. Unfortunately there is often great reluctance even among experienced hobbyists to cut back an overgrown begonia for fear of losing potential flowers. Surely it is desirable to sacrifice one season of bloom to develop a beautiful specimen plant.

B. 'Medora'. Cut back long shoots after flowering is complete	B. pustulata argentae. Trim off long narrow rhizomes.

Recently I gave a drastic pruning to a very old plant of B. 'Maphil'. The pot was overflowing with dangling rhizomes and the old rhizomes were covering those at the crown. All the rhizomes were cut off, leaving only those at the crown, and fresh soil filled in around those remaining. Our readers may be interested to know that the plant of B. 'Maphil' pictured has been in the same pot for 7 years and has been subjected to this drastic pruning three times. The old rhizomes shown in the photo when placed in a bowl of water produced roots within two weeks and the old plant started to show new leaves within three weeks.

B. 'Maphil'. Start by cutting off dangling rhizomes.	B. 'Maphil'. Plant is denuded of all rhizomes that were above pot level.

Drastic pruning is also desirable if your plants have been badly damaged by mildew or have become extremely unsightly whether due to insect damage or damage by rain, hail or some other aspect of the weather. Do not discard such plants but cut them back to within 4 to 6 inches of the pot level and treat with insecticide and fungicide. They will recover and become more beautiful than ever. It has been my experience that some varieties that normally rest in winter and being grown in a cool room or greenhouse may not begin to show new growth until spring, if such drastic pruning is done in the fall or early part of winter.

Photos by Walter Haring.