Hardy Mums - Is There Such a Thing?

This paragraph in my last post regarding mums has raised some discussion among plantsmen and bloggers and home gardeners and I appreciate those that have shared their views. This interaction that social media and the internet fosters is what I love most about it.

We're talking garden mums here - the ones that are hardy to  my Zone 5b - not the florist mums, which aren't. So if you want your mums year after year, make sure you're buying garden mums. Ask the garden center if you aren't sure.

In reality, that's putting it a little too simply and may be misleading to some. That's the last thing I want to do - mislead ANYONE. So let's have a little more discussion on this issue.

Chrysanthemum 'Amur Coral'

It's not so cut and dried, as is the case with many things in the garden, because there are so many variables. There's the soil, the location, how it's planted, pruned and protected, and of course, there are those climatic issues of temperature, wind, snow cover, and even altitude that determine whether any plant will survive winter, whether you're in Zone 3 or Zone 7.

Before we get into all that though, let's talk about the types of mums that are available.

• Garden mums - Generally hardy to Zones 5-9, spread by underground stolons. Includes the "daisy" mum like 'Clara Curtis' and 'Sheffield Pink', and those labeled Chrysanthemum x. rubellum. May also be known as Korean mum. Chrysanthemum x. morifolium is also considered to be hardy in these zones, but is not as reliable in the colder end of that spectrum.


• Florist mums - These do not have the same type of root system as garden mums. They do not reproduce via stolons and will not survive a frost. They do come in interesting petal patterns though, such as yellow and red striped.

The thing is, with ANY mum you plant that's supposed to be hardy, they stand the best chance of surviving winter if they're planted in the spring. That's not likely to be the time that you're thinking about mums, given that they bloom in the fall, but if you want great blooms and longevity, spring planting is the way to go. That gives them time to become established, which will make them better able to withstand stresses during their first winter.

Chrysanthemum 'Rhumba'

Once your mums are done blooming in the fall, you can deadhead the blooms if you want (I don't), but only the blooms. If you leave the browning foliage on all winter, that will help not only to protect the roots, but it will provide a catch-all for snow. As you know, snow cover helps protect plants in the winter, too. A few inches of mulch around the base will further help insulate the plant's roots in two ways - it will keep them warmer and it helps protect against excessive freezing and thawing cycles which can cause heaving, leaving roots exposed to cold winter temperatures and frigid air. Perennial roots of any kind don't like that very well.

Chrysanthemum 'Matchsticks'

In any case, mums are fairly inexpensive, so if you buy mums for fall decorating purposes, then plant them in the ground and they fail to make it through the winter, you really won't be out much. But following these tips will give you a better chance at success.

My own experience here in NW Ohio Zone 5b is that once I was careful during planting to make sure I amended our heavy clay soil to give them better drainage and didn't plant them in a low spot, I've not lost any, whether they be daisy mums or garden mums. I don't even bother buying florist mums, because I really want all of them to stick around for more than a season, if possible.

On the other hand, I've heard from one of my gardening friends in Illinois (also Zone 5b) that he's never had a single mum return. He also can't get fall-blooming Japanese anemones (Anemone hupehensis var. japonica) and Toad Lilies (Tricyrtis sp.) to survive our winters, so not everyone has such great success. A trusted grower has also expressed that perhaps I'm lucky, but I see a great number of mums in the ground every fall around here that I know weren't just planted each year. So your mileage may vary...

Chrysanthemum 'Clara Curtis'

Do you have any thoughts to add or experiences to share?

For further reading:

All About Mums (Better Homes & Garden)
Northern Hardy Garden Mums (AgWeek.com)
Growing Chrysanthemums in the Garden (Iowa State University Extension)
Faribault Growers, Inc.
National Chrysanthemum Society