Good Growing

Welcome to the Good Growing podcast. I am Ken Johnson, horticulture educator with University of Illinois Extension, coming to you from Jacksonville, Illinois with a garden bite. And today, we're gonna talk a little bit about chrysanthemums or mums. Now that we're heading into the fall, mums are starting to show up in nurseries and garden centers and grocery stores all over the place, and mums are a staple plant for a lot of our landscapes in the fall. They provide some much needed color when a lot of our garden plants are starting to decline.

If you've gone out shopping for mums or been to a nursery or garden center, you've probably noticed there's a wide variety of different bloom colors available. Flowers can range from green to yellow, orange, bronze. You can find burgundy, red, pink, purple, and white flowers. So there's a color for everybody that's out there. You can also find a variety of different flower shapes.

So we have things like cushions, are double flowered, that have compact growth. We have daisies, which have single flowers. As the name implies, they look like daisies, and they have yellow centers. There's decoratives, which have double or semi double blossoms, but they are on larger plants. There's things like pom poms and buttons.

So again, there's a diversity of flower shapes and plant sizes as well. A lot of people treat mums as annuals, but mums are actually hardy from zones five to nine, meaning we can grow them outdoors in Illinois. Or at least they will survive outdoors in Illinois. However, a lot of people that plant their mums outdoors struggle to get them to survive throughout the winter. So what are some different things we can do to help our mums survive and make it through the winter in our landscapes?

One of the biggest reasons mums fail to overwinter, at least in Illinois, is that we are typically trying to plant mums when they are most commonly available in the fall. Unfortunately, the best time to plant them is going to be in the spring. Planting them in the spring is going to give the plants ample time to establish themselves, grow new roots, and stuff like that. So if you're planting your mums this fall, get them in the ground as soon as you possibly can to give them the most amount of time to establish themselves in your landscape. Mums are also fairly shallow rooted plants, which makes them prone to heaving during the winter.

So heaving is going to be caused by repeated freezing and thawing of the soil, so that just kinda works things out of the soil, and that can severely damage or kill plants because those roots are now exposed to the cold winter air, and they'll dry out and it just gets too cold for them. To help prevent this, we can apply some mulch up to four inches of it around our plants. And this is going to help moderate that soil temperature, prevent those wide temperature swings, and reduce heaving. Additionally, because mums are shallow rooted, they are also a lot more prone to drying out than some of our other landscape plants, and drought stressed plants are going be less likely to survive in the winter than well watered plants. So you may need to water them if conditions become dry in the fall.

An additional benefit to mulching, besides reducing the amount of heaving, is that mulching is also going to help retain some of that soil moisture, so you don't need to water as much. Regardless of when you're going to be planting your mums, whether that be the spring or the fall, you want to put them in an area with moist, well drained soil. Mums are one of those plants that don't like quote unquote wet feet, so you want to try to avoid low spots or areas that have heavy soils that retain a lot of moisture in them. You also want to place your mums in a site that receives full sun, so at least six hours of direct sunlight. It can also be helpful to place your mums in a protected location if you're going to be trying to overwinter them.

Plants that are out in the open are going to be exposed to more extreme conditions. You think about our cold winter winds causing desiccation and things like that on the plant. Providing them a protected location can help them survive the winter a little bit more. So once you've planted your mums in your landscape, once they start to go dormant in the fall, those flowers are done, the leaves start browning, and everything just kind of starts dying back. You want to avoid that temptation to cut everything back.

A A lot of people do this to kind of clean up the landscape, make it look a little bit neater. But leaving that old growth will help add an additional layer of protection to help get your plants through the winter. It can catch leaves that blow by, and again, provide a little bit more insulation to the crown of that plant. Once growth resumes in the spring, if you've successfully overwintered them, that's when you can start removing that old growth. So once you start noticing new growth in the spring, you can remove all of that dead stuff.

When that new growth gets to be about six inches long, you want to start pinching or removing those growing tips. And this is going to encourage bushier plants. So they're not going to flop as much, you're going to get more flowers on those plants if you pinch back those growing tips. Usually, could do this about two to three times during the growing season, with the last one taking place in late June or early July. July 4 holiday is an easy way to remember this.

And again, because these are shallow rooted, you want to make sure you're providing them with water throughout the growing season if conditions get dry. If you successfully overwinter your mums and you've had them in your landscape for a few years, they will benefit from being divided every few years. This is also going to be best done in the spring as new growth starts to appear on plants. So you're gonna want to dig up those plants, divide them, get rid of any dead areas. And when you're dividing, you want to make sure you have several shoots and a good root system on each plant, and then go ahead and put those back in your landscape.

One problem people run into if they have successfully overwintered their mums is that they don't bloom again for them in subsequent years. Mums produce flowers based on day length. So mums are going be short day, or more accurately, long night plants. This means that the plants will not start producing flowers until a certain number of hours of darkness has been reached, or the critical night length. So when you're out looking for plants, you may have noticed that sometimes mums are labeled as early or late season.

So these early season types don't need as much darkness in order to initiate flowering. So one reason mums may not be flowering for people is that they have a cultivar that requires long periods of darkness, and we may just get a killing frost before they can produce flowers. So florist mums would be an example of this. They have a longer critical night length than some other types. Another possibility is that somehow that dark period that your plants are being exposed to is interrupted.

A lot of times we see this when plants are planted near street lights or house lights. When those turn on, that darkness gets interrupted, and that can delay flower production. So there's some information on planting mums outdoors. If for some reason you can't get your mums in the ground, but you want to try overwintering them, you can overwinter them indoors. After they we've had a hard frost, put your potted mums in a cool, dark location, then bring the pots outdoors when it begins to warm up in the spring, and then you can plant them in your landscape.

That's all I've got for you for this week's Garden Bite. Thanks for listening, and keep on growing.