Wait! Before you get ready to toss those potted chrysanthemums onto the compost heap, with just a little bit of care, you can keep them going – and growing – as part of your landscape with these helpful tips:
Know Which Mums You Have – Most potted mums fall into one of two categories: florist mums and hardy mums. Florist mums are usually potted or gift plants you find in the spring. Their roots are shallow due to their being treated with growth-regulating hormones to keep them compact in their containers, which makes them poor candidates for withstanding the cold temperatures in our area. Hardy mums are the ones you’ll find at the garden center in the fall and are more suitable for our growing zone.
Planted or Potted – Did you plant your mums into the ground when you got them or did you leave them in their pots? If you planted them in the ground for display around mid-October, they can most likely be left to overwinter. Mums need a good 4-6 weeks before the first frost to develop a healthy root system to get them through the colder months. Don’t cut these back until spring, since the foliage will provide added protection for them during their first winter and hold off on dividing them until spring. Make sure they have adequate water before frost arrives and add mulch for even more protection.
If your mums are still in pots, it’s too late to plant them in the ground now, but you can still keep them and plant them in the spring. The key is to protect the pots from being subjected to a hard freeze, which will damage or kill their roots. Potted mums can otherwise survive cold temps and light frost. Be sure to move your mums to a garage or covered porch if frost is forecasted. When temps become consistently cold, it’s time to move your potted mums indoors. Before bringing them in, cut the mums back to just a few inches above the potted soil line. Store in a partially heated garage or cool corner of the basement. You want the plants to go dormant without freezing. Water them lightly every few weeks or so during the winter.
Transplanting Mums in the Spring – About four weeks after the last expected frost and when your mums starts to show some new growth, it’s time to transplant them. You’ll need to harden them off before bringing them outdoors. Place the pots in a partially sunny location to get them use to light conditions before setting them outside. In the meantime, determine the best location outdoors for your plants. Mums need at least 6 hours of sunlight each day, and prior to planting, it’s a good idea to amend the soil with compost or organic matter to improve drainage and aeration. A point to remember; shortening day lengths are what stimulate mums to bloom, so avoid planting them in spaces exposed to artificial lights such as porch or streetlights. Don’t bury the plants too deeply – keep them at the same level they were growing inside their containers. Allow for enough space around each plant – generally about 18” or so – to encourage healthy air circulation, which will help prevent diseases. Lightly mulch the soil around the plants and deadhead spent flowers.
You can also replant mums into pots – just be sure to use fresh potting soil and divide them if roots are crowded. Mums also do well in raised beds, especially if your garden soil has a lot of clay in it and tends to be boggy.
For mums that you had planted in the ground the prior fall, spring is the perfect time to divide them. Discard the center of the flower clump and replant the vigorous outer roots.
Caring for Mums in the Summer for Fall Blooming
Mums do better when their stems are short, which helps prevent them from flopping over. As summer approaches, pinch the blooms off of the mums early and cut them in half by July. This will keep the foliage of the mums compact and allow for the flowers to bloom in the fall and not in late summer.