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written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Chrysanthemums are glorious perennials for fall. For proof, take a stroll through the Master Gardener Demonstration Garden in Kennewick and find the Japanese Garden. For the next month, you’ll see a beautiful display of mums. However, a visit to this gorgeous garden might leave gardeners with some questions…

Question: The mums on display in the Japanese Garden are covered with flowers. Mine have some flowers, but not that many. What’s the difference?

Answer: Mums are easy to grow and require little attention. Late last fall, I took two mums that had been in my fall container gardens and planted them out in my garden. They came out of four-inch pots and have more than quadrupled in size over the summer, but like your plants, mine are not covered with flowers this fall. That’s because I didn’t “pinch” them.

The trick is “pinching” them throughout the growing season to make them bushy. This will also lead to the production of more flowers. Pinching involves removing one-half to one inch of each shoot back to a pair of leaves using your thumb and forefinger to “pinch” off the growth. For more flowerful mums, pinch when the new growth is about six inches in length and again every two to three weeks until late June or early July.

Question: I have problems with mums not making it through the winter. Are the breeders sacrificing hardiness to create prettier flowers?

Answer: First, make sure you’re planting what are considered hardy mums, not florist mums. Chrysanthemum plants sold in flower shops as floral gifts are usually not hardy. When you purchase hardy garden mums, check to make sure that they’re rated as hardy in Zones 6 or lower. There are a number of very hardy mums on the market. That’s because breeders have worked to develop hardy mums that will survive in much colder zones than ours, such as in Minnesota.

If you’re having a problem with hardy garden mums that you plant in the fall not making it through the winter, try planting them earlier in the fall months, at least six weeks before the first anticipated frost. You could also try planting them in the spring so they become well established before severely cold winter weather arrives. Be sure to water fall plantings during mild fall and early winter weather.

Other things you can do to improve mum survival include mulching with bark after the weather cools, leaving the dead frosted tops of the plants in the garden until spring, and not fertilizing the plants after the end of July.

UPCOMING CLASSES: It’s not often that I get excited about waiting in a doctor’s office, but I did last week. In one of the waiting room gardening magazines I found instructions on how to make a bird bath with concrete and a pumpkin. I plan to make one out of “hypertufa” instead of concrete so it won’t be quite so heavy to lift. What is hypertufa? It’s a mix of Portland cement, peat moss, and perlite or vermiculte that creates a lighter weight mix that can be used to make stone-like planters using a mold.

Published: 9/26/2009 10:45 AM


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

The end of the summer may be here, but that doesn’t mean the end of all the garden flowers. Fall flowering perennials can provide some glorious color to accent the change of season. On the top of the list is the tried-and-true garden chrysanthemum. You can already find them prominently displayed for sale at local garden centers and department stores. Bright yellows, rich golds, dark fuchsia, deep burgundy, pretty pink, white, lavender and more! Garden mums announce the arrival of fall… just like tulips and daffodils are harbingers of spring.

Garden mums may look just like florist mums, but they are different. Florist mums are tender and usually killed by freezing winter temperatures. Garden mums are able to endure winter cold temperatures by means of stolons or underground stems. To insure their survival, it’s best to plant garden mums in the spring. However, the fall selections are hard to resist… so be sure to plant mums at least six weeks before the average first killing frost in the fall. (The average date of our first killing frost in the fall is between October 1st and October 15th. That means this weekend is a good time to buy and plant garden mums.)

Be sure to water the plants in and then keep the soil moderately moist during mild fall and early winter weather. Whether a new planting or an established one, don’t prune mums back in the fall. Instead, prune them in early spring. To create a bushier mum with more blooms, be sure to “pinch” back the soft growth in the spring when the shoots are about four to six inches long. “Pinching” means to remove the growing tip and the youngest set of leaves with your fingertips. Repeat the pinching process every two to three weeks until late June. The result of all this attention is a bushy garden mum with lots of flowers and color.

Another spectacular fall flower is the New England aster. I have to admit that I was never too impressed with asters when I was growing up, even though they are my “birth flower.” Many asters provide some color in the garden are less than spectacular. That isn’t the case with some of the newer cultivars. My favorite is ‘Purple Dome’ (Aster novae-angliae

Purple Dome


In fact, a ‘Purple Dome’ plant is growing in front of my office at the Benton County WSU Extension Office in Kennwick in the Low-Water-Use Landscape Demonstration. A few bright purple daisy-like flowers have just started to open on this outstanding plant. ‘Purple Dome’ grows into a compact mound that’s 18 to 24 inches tall and wide. Unlike many garden asters, it’s not prone to problems with powdery mildew.

An added bonus with ‘Purple Dome’ and other asters is they attract butterflies. There a number of different types of perennial garden asters. These tend to be larger plants with purple, pink, or lavender flowers. These larger types will also benefit from pinching back several times before midsummer.

Like many other flowering perennials, the plants of garden mums and New England asters will need dividing after several years to keep them vigorous and blooming well. Every two to three years, dig up your garden mums and asters to divide them. Since these plants bloom in the fall, they should be divided in the spring as soon as new shoots start to appear. (Generally, spring blooming perennials are dug and divided in the fall.) Use a sharpened spade to remove the centers which are the oldest and often unproductive part of the plant. Then take the spade and divide the “good” part of the plant into several sections. The good sections of the plant can be replanted in your garden or shared with other gardeners.

Published: 9/1/2007 2:37 PM



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