MISSOURI BOTANICAL GARDEN BULLETIN 33 



broom or hand sprayer. During some seasons leaf-rollers and 

 caterpillars are troublesome, but they may be controlled by 

 spraying with arsenate of lead (one pound to 25 gallons of 

 water) or by hand-picking where the number of plants is small. 

 Winter Protection. — The hybrid perpetuals are sufficiently 

 hardy to withstand the winter without protection, although 

 some covering will do them no harm. The simplest method 

 to protect hybrid tea roses is to pile the soil around the base 

 of each plant and then fill in between the bushes with coarse 

 manure. This should be done about the latter part of 

 November. 



Pruning. — Before growth begins, usually in March in this 

 locality, is the best time to prune roses. If one desires mass 

 effect in a rose garden, the plants should be pruned only 

 moderately. However, if good flowers for cutting are the 

 object, the plants should be pruned severely, leaving from 

 3 to 6 inches of growth on the weak-growing plants, and 8 to 

 10 inches on the stronger ones. For exhibition flowers roses 

 should be pruned to two buds. Whenever possible, the cut 

 should be made about one-half inch above an outside bud, so 

 that the leading shoot will grow outward from the bush, leav- 

 ing the center open. All weak and dead wood should be 

 removed. Hybrid perpetuals do not require severe pruning 

 if a large number of flowers are desired (pi. 14). Polyantha 

 and climbing roses require very little pruning. 



THE ROSE GARDEN IN THE MISSOURI BOTANICAL, GARDEN 



IN 1920 



The first half of the 1920 season was unfavorable for the 

 proper development of roses. During the mild weather the 

 latter part of March the plants produced a quick and vigorous 

 growth, only to be destroyed by a snow and a sudden drop in 

 temperature the night of April 4. Recovering from this 

 shock, the roses grew T well and bloomed abundantly the latter 

 part of May and the first of June. However, the second week 

 of June was extremely hot followed by a week of very cool 

 weather, and except for a shower on June 22, no rain fell 

 until August 7. By the middle of August the bushes were 

 again clothed with fresh foliage and the hybrid tea roses 

 continued blooming until checked by frost on October 28. 

 The only necessary spraying was for the aphis. Some leaf- 

 rollers appeared, but these were cheeked readily by hand- 

 picking. Several dustings with sulphur controlled the mildew. 



The accompanying report on the behavior of the tea, hybrid 

 tea, and polyantha roses, grown in the Garden in 1920, will 



