The Secret Behind Those Perfect Mums

• Sep 14, 2026
• by Rebecca Auchter

If you've ever wondered how garden center mums get so perfectly round and completely covered in flowers, here's the secret: they don't naturally grow that way! 

The beautiful, mounded mums you see for sale in September have been carefully grown and pinched back throughout the spring and summer. Regular pinching encourages the plants to branch and become full and rounded instead of tall and floppy. Then, growers time their production so that the plants burst into bloom just as fall arrives. That’s why garden centers are suddenly filled with perfectly shaped mums covered in flowers—all at nearly the same time.  But here’s the part many gardeners don’t realize: those mums can be planted in your garden and come back next year. Here in Pittsburgh, chrysanthemums are hardy perennials when planted in the ground and given the right conditions.

Want Your Mum to Return Next Year?

Plant your mum as soon as you can in a sunny location with well-drained soil. Dig a hole about twice as wide as the root ball, but no deeper than the container. Water it thoroughly after planting and keep it watered regularly while the roots become established.  Once the flowers fade, don’t cut the plant all the way back to the ground in fall. Leave the stems and foliage standing through winter. This provides some protection for the crown of the plant during our cold Pittsburgh winters.

In spring, when you see new growth emerging from the base, cut away the old stems and let your mum grow. If you want that familiar, perfectly rounded garden center shape, you can pinch the growing tips back several times during late spring and early summer. Stop pinching around mid-July so the plant has time to develop its flower buds for fall.

So enjoy that perfectly round mum while it lasts—but remember, it doesn’t have to be a one-season plant. Give it a home in your garden, and your fall color can return year after year!