106 PLANT PROPAGATION 
September on a shady north border covered with a 
frame or handlights or in pots in cold frame until 
callused, then placed in gentle bottom heat to assist 
root formation. With some species side-grafting is 
also practised on 2-year-old stocks placed in a close 
frame, ventilating for an hour each morning to dispel 
excessive mioisture. 
ConvoLvuLus.—The dwarf and climbing kinds so 
much grown in gardens should be sown in April in a 
sunny position where they are to flower. 
CoreEopsis.—Sow seeds of annual kinds outside in 
April. Propagate perennial kinds by young cuttings in 
a cold frame in summer or by division of the roots in 
autumn or spring. 
Cosmos.—Sow seed in gentle heat in March to plant 
out in May. 
CoTONEASTER.-—Propagate by seed sown in spring, 
also by cuttings under handlight and layers put down in 
autumn. 
CouveE TRoNcHUDA (PORTUGAL CABBAGE).—Sow seed 
in March or April on open border. 
Crassula (Rochea).—C. jasminea is an_ excellent 
market plant. It can be propagated by cuttings in 
spring and even more easily by pulling old plants to 
pieces after flowering and planting stems from which 
roots are already growing. 
Cuttings of the old favourite, C. coccinea, should be 
made from non-flowering shoots with the lower leaves 
removed, slightly drying the cut portion by exposure to 
sun and atmosphere before inserting them in June, 
standing the pots on a greenhouse shelf and watering 
sparingly until rooted and making growth. 
CrataGcus.—The haws should be collected when fully 
