Instead of wilting, as do most plants when they become excessively dry, 

 begonia leaves take on a lighter color but remain erect. The result of 

 such drying may first appear as browned or scorched margins of the 

 leaves, eventually leading to the death of all or parts of the leaves 

 affected. 



Temperature 



Begonias are tolerant to a wide range of temperatures, providing 

 good light conditions are available. One Calla begonia failed in a north 

 window with a night temperature above 70° F. The seinperflorens 

 group of begonias are less tolerant to high temperatures than some other 

 begonias that are grown primarily for foliage. A\\ of the successful 

 plants in these experiments were grown at night temperatures below 70° 

 F, with the majority grown at 50° - 65° F. 



Insects 



That there was no insect trouble on any of the 54 begonias in these 

 trials is indicative of their relative freedom from pests. However, 

 aphids, mealybugs, thrip, and mites may trouble begonias in some in- 

 stances. Except for some damage to open flowers, begonias may be 

 washed regularly to keep them clean of insects. 



Key to other troubles 



1. Good growth but failure to bloom may be caused by insuffi- 

 cient light. 



2. If leaves and stems take on a reddish cast and growth is re- 

 tarded, the trouble may be caused by too much sun, usually but not al- 

 ways, coupled with drying. 



3. A scorching of the margins of the older leaves is usually caused 

 by inadequate soil moisture, or an overly rich soil, or both. 



4. When leaves and flowers fade in color, growth becomes long- 

 jointed and spindly, flowers usually become smaller or the plant may 

 fail to bloom entirely, the plant is suffering from a lack of light, too 

 high a temperature, slightly too much moisture, or a combination of 

 these factors. 



5. If all or part of the plant rots off at the soil surface or an exami- 

 nation of the root system reveals rotted roots, overwatering is probably 

 the cause. 



Additional notes on the Calla begonia 



Some strains are more vigorous and more easily grown than others. 

 Vigor seems to be tied in with the amount of green coloring in the 

 leaves. Those strains that tend to form new basal shoots that are solid 

 green for some time before developing the calla formation seem to be 

 much easier to grow. The white leaves tend to be parasitic on the 

 srreen ones for thev are not able to manufacture food. The more white 

 leaves there are present the less vigor the plant will have. 



Calla begonia can be grown from seed although the seedlings will 

 not be uniform. By growing a number of seedlings to maturity it is 

 easily possible to select desirable plants that may then be reproduced by 

 slips. 



Twenty-two 



