I bought an amazing canna plant this year which thrived all summer. It’s in a large pot, in potting compost, sunny position. In the last couple of weeks the leaves are turning brown/black. The compost is dry to the touch. Is this normal for them in winter? Do I need to put fleece around them? How about watering?
Canna is half-hardy, okay for the summer outdoors. The foliage is knocked back by frost and withers. The roots need to be protected against a very hard frost. ideally by being brought into a greenhouse or conservatory or a frost-free shed. If it cannot be brought under cover, it could be wrapped up in cold weather with bubble wrap or fleece or some such. The withered top can be cut away or left for a measure of protection.