All there is to know about mums

9/29/2010

If you are looking for that late fall showoff, you don't have to look any further than the chrysanthemum. These balls of color come in shades of almost every color in the rainbow and will last through the first frost.

Mums are easy perennials to grow, but many people treat them as annuals and replant them every year.

Here's what you need to do: If you buy them now, put them in the ground right away, water them thoroughly and enjoy their blooms. Before the ground freezes, mulch them with about three to four inches of mulch around the base.

"Mulching them will help keep their roots frozen over the winter and you can cut them back in the spring," says Joe Stasa, head grower at Ohlman Farm and Greenhouse in Toledo.

Don't cut them back yet. Stasa says many people make the mistake of cutting them back in the fall, or planting them too shallow. This stresses out their roots. Shallow planting can cause them to heave out of the ground over winter and pruning them too early can also cause stress.

"In the late spring, you will start to see growth on the plants, that is the signal to trim off the old branches," Stasa says. "They will easily break off with your fingers."

In mid-July, it is time to pinch them back again. You want to keep the plant low with lots of flowers, so pinching them back will cause each stem to grow side shoots and you will get double the number of flowers by pinching them back.

"Make sure you don't cut them back after mid-July or you will be cutting off all of your fall blooms," Stasa says. "And fertilize them with a balanced fertilizer every couple of weeks."

They will continue to flourish for two to three years, then you many have to divide the clump. The best time to divide them is in the spring, he says.

"Sometimes you will see the color of the flower change. It is because the genes of the plant change from year to year. Your plant might start out as a light yellow, then a couple years later turn into a darker shade."

Do you have a natural mum or a shaded mum?

If you are scratching your head wondering what the difference is, the answer is light.

Stasa says it all depends on how much light they get. According to Stasa, "Usually, mums should start to bud around Labor Day. That's when you know you have a natural mum. If you see mums for sale right now that are a little bigger than the rest and just starting to bud out, those are two other ways to tell that you are buying a natural mum."

Stasa says natural mums will last more seasons in the garden just because they aren't forced to bloom before their time.

They stay within the natural cycle of growth and bloom when the daytime temperatures are cooler. Those characteristics put less stress on the roots of the plant and will help it live longer.

Shaded mums are any variety that has been forced to bloom earlier than their natural cycle.

Chrysanthemums are sensitive to the length of daylight and rely on that to start their blooming cycle.

Stasa says once they start getting 13 hours of darkness, then they start to bloom. Growers will cut down their daytime hours by pulling a shade over the plants early in the day, and again at night.

"We like to have mums blooming by late July, so we count back five weeks from the time we want them to bloom and that is when we start cutting back on their sunlight," Stasa says.

In June we shade them before the sun comes up until about 9 am. Then, we will pull the shade off for the rest of the day. We will go back in the early evening and pull the shade again around 7 p.m. to give them just over 13 hours of darkness."

Shaded, or forced mums, already have been put under a little stress. They are forced to bloom a little early and also are blooming during the hottest part of the summer in late July and August.

"Shaded mums will fade faster," Stasa says. "It makes them a little less hardy than naturally blooming mums."

Contact Kelly Heidbreder

at kheidbreder@theblade.com.