- For winter protection, mulch with 10 to 15 centimetres of pine needles or straw in mid- to late November or when the temperature drops to 0°C and soil surfaces freeze.
When to divide your plants
- Divide mums every two years or so. It's time to divide when plants are large and bushy and many new shoots come up in early spring. Remove new offsets carefully, keeping as much of their root system intact as possible.
- Transplant into new areas or into pots for later placement. Set the division at the same level (or slightly deeper) at which it was growing and mound up the base with a few centimetres (five or less) of soil. Plant at least three shoots in a triangular pattern.
- Stake tall plants. You can reduce powdery mildew by maintaining good air circulation around the plants. Though mums are susceptible to aphids and mites outdoors, beneficial insects usually take care of the pests.