136 THE UNHEATED GREENHOUSE 



bushy growth, otherwise they may run up with a bare 

 unsightly stem. If they are allowed to go ahead at their 

 own sweet will, it is a difficult matter to bring them back, 

 later on, into good shape. The time at which pruning is 

 done is also of great importance. Too often the cutting back 

 of a plant or shrub is neglected at the right moment then, in 

 a fit of energy and ignorance, we set to work and find, too 

 late, that we have diligently cut away every hope of flowers for 

 the coming season. Deutzias flower on the young wood, and 

 any cutting away that is needed of the old branches should be 

 done immediately after flowering. Clematises may be taken 

 as another familiar example. The purple C. Jackmani 

 flowers in the autumn on the new growth of the current year, 

 and requires pruning back during winter before the shoots 

 begin to break. C. montana, as well as those of the large 

 earlier-flowering type (like C. lanuginosa), bloom, on the 

 contrary, on the wood of the last season, and merely need 

 thinning out, or must be cut back very sparingly when 

 flowering is over. The same rule applies to the charming, 

 half-hardy New Zealand species, C. indivisa. Many of the 

 fine hybrid forms of Clematis succeed well, not as climbers, 

 but in small pots, and are particularly well adapted for an 

 unheated greenhouse. 



Roses on their own roots of the less vigorous type, such 

 as Catherine Mermet, are often sufficiently pruned by cutting 

 their flowers with a tolerably long stem, whereas stronger- 

 growers are the better for harder cutting back. A few shrubs, 

 like Brugmansia and Desmodium, will bear cutting down to 

 the ground level after flowering, and succeed all the better for 

 such drastic treatment. 



