Answer: Your Cordylines are hardy to about 20F so if you want to keep them over the winter, you'll need to take them indoors. Pruning should be light - remove only the spent foliage (usually the oldest, lowest leaves on the plant). I agree, they are spectacular in appearance, but I treat mine as annuals rather than attempt to keep them over from year to year. They can get quite large (15' tall, 8' wide) with maturity. Best wishes with your garden!
Q&A Library Searching Tips