Gardening with Gary

Gardening Advice from an Expert

Chrysanthemums

Q. I have a pot of mums from last year. Will they come up again this year? If they will, do I need to cut the dead leaves and stems? If I do, what do I cut them with? I'm new to gardening.

A. Mums are generally hardy enough to go through winter and grow and bloom the next year, though I do not know your climate zone. A particularly harsh winter might kill it. You will find out soon enough if there are any green sprouts popping out with the warm spring temps.

Cut back all old stems and leaves down to the soil, if they are indeed totally brown. Your neighbors have not got around to their spring cleaning, so you go show them! There is no advantage in keeping the old dead wood on mums or any other plant once it has come through the winter and ready to put forth the spring growth.

One should always be aware that dead tissue is a great harbor for disease and insects, especially where they love to lay their eggs. You can avoid many problems in your gardens by keeping them clean, well-pruned and healthy.

Give the mums a good helping of fertilizer once you see new growth. A basic gardening fertilizer is fine for mums and almost all your other perennials. Maintain this program coupled with good watering throughout the entire season, especially when the heat is harsh on the plants and you are not experiencing rainfall. Help out Mother Nature, and your plants will be all the more happy.

Q. I have just planted 2 flats of fall mums. They are in bloom now. The mum lady at the store said not to cut them back now for fall blooming, but rather wait and cut them back this fall. Will they get leggy, only flower now, or should I ignore her and prune them now?

A. She is correct, but it is a combination of her response and yours! You should let them bloom now, and of course plant them into your well-worked garden beds. Add a bit of mulch around them and make sure their location will have at least half day sun, full being even better. Enjoy the flowers.

Then as the flowers fade, you will cut the heads off and discard. Use clean, sharp shears. This will force vegetative side shoots so that you will not have leggy stems throughout the summer. I would not pinch back anything except an errant branch which seems out of kilter with the rest of the plant. All pinching will eliminate any chance of flowering this fall.

Since they were forced to bloom now, by tricking them with short days in a greenhouse, you probably will not get much in the way of flowers this fall. It could be sporadic at best. But, you must keep them green and growing all season with ample water and fertilizer to build up the root system and get them established in their new home.

S. kisko writes~ I have 14 mum plants in my garden. How do we care for them to keep them coming back each year? They are dying now. Can we cut the flowers now? They are very heavy and beginning to split.

A. You should cut off all old flowers which are brown and faded. After all the blooming is over for the fall, cut the entire plants back to about 6". Mulch them with bark or dried leaves and ready them for the dormancy of winter.

A flowering mum should remain full of color approximately 4 to 6 weeks. When flowering has ceased, remove dead blooms. Allow the foliage to remain until it is time to prepare them for winter. Around Thanksgiving, it is time to provide some winter protection for your mum. Cover the mum completely with sphagnum peat moss and water thoroughly. Many people use leaves, straw or soil as a mulch.

In the spring, after the danger of frost is past, remove the peat moss mulch. Remove any dead stems at this time. If the plant survived the winter, short green shoots of new growth should be seen by May 1. A conscientious effort to provide this care will result in a lifetime enjoyment of mums.

Mums require pinching to insure a compact, full plant. In the Midwest, garden mums will naturally set buds anytime after mid-May for flowering about 4 to 6 weeks later. So pinch no later than July 4 for blooms in August. In the spring allow the mum to grow to 6" tall then prune to 3". Continue pruning 2 to 3 inches off of each new 6" growth until July 4.

Mums need fertilizer for strong foliage growth and good root development. Fertilizer will also promote blossoms and keep them lasting longer. We suggest you fertilize throughout the spring, summer and fall. Use a water soluble fertilizer, as Miracle-Gro, every other time you water, or use a granular garden type fertilizer as a top dressing around the mum at least once a month. This is an important step in developing a strong healthy plant. Fertilizing would not have to be done to established plant, but if done it will produce a much nicer plant.

With assistance from: www.bennettsgreenhouse.com

Q. I need to know if there is anything I need to do for my mums before winter. I just got them this fall. I have "garden mums" and "chrysanthemum". I live in the center of Ohio.

A. Garden mums are not difficult plants to grow. You can buy and plant them almost anytime. They start out as small, rooted cuttings in the spring. Plant these after the last frost in full sun. For outdoor hardiness, spring-planted mums have a better chance to get their root systems established well enough by fall to survive the winter. The plants will thrive in a wide variety of soils, but do need good drainage. Incorporate compost or well-rotted manure into the planting hole. You can also feed them in early fall with a 5-10-10 fertilizer. If the weather is dry, make sure they get adequate water, about an inch per week.

Aside from getting them started, mums' only special demand is some attention to pruning at the correct time. They are stimulated to bloom by the declining day length of summer and early fall, and to some extent by a late-summer pattern of warm days and cooler nights. Pinching out the growing tips (even if they already have tiny buds) until about July 15 will make the plants bushier and keep them from trying to set blooms too early. Or pinch side shoots on a stem leaving one terminal bud, for larger flowers.

You can find garden mums in nurseries all summer long and into fall. These will probably be in pots ranging from 4 to 8 inches in diameter. If you do plant mums in fall, the plants will have a better chance of making it through winter with a thick layer of mulch. As the mum blooms fade, deadhead them to avoid having any stray seedlings come up. But it is best to leave all the foliage in place until spring. A number of tests have shown that mums survive the winter better if the dead tops are not pruned until the danger of heavy freezes is past. They will turn brown, but the plants will retain much of their structure and add winter interest. Also, many greenhouses offer larger, preplanted containers and hanging baskets. If you get these larger plants, the pinching will have been done for you, and the only thing you have to do is provide a good planting site and plenty of water.

If you want more plants from your garden mums, they are easy to divide. In fact, cuttings and division are the only ways to get the same variety, as hybrid mums do not come true from seed.

Carefully dig up a clump of mums in spring, then gently separate it into smaller sections. You can get a lot of plants from a clump because all you need for a new start is a small sprig with a little bit of root. Replant divisions just as you would potted starts from the nursery.

In late spring to midsummer, look at garden centers for pots of plants budded out and some could be getting ready for early bloom. If nothing else, you may be able to decide which ones to get next spring. And I will bet you will not go home without picking up at least one container of colorful blossoms to brighten up the fall.

Credit to: Timothy Skeers From Garden Gate Issue 35, October 2000

Q. I was wondering what the proper times during spring and summer, to "cut back" my mums would be to ensure fall blooms. I was also wondering what time of the spring I should cut back the dead growth from the previous fall. Any pruning and feeding information would be helpful.

A. Mums require pinching to ensure a nice, compact plant. Garden mums will naturally set buds anytime after Mid-May for flowering about 4-6 weeks later. So, pinch no later than July 4th for blooms in August. In the spring, allow the mum to grow to 6" tall, then prune to 3". Continue pruning 2-3" off each new growth until July 4th.

Do not forget to feed the plants all through the spring and early summer, with a general gardening fertilizer, like Miracle-Gro, according to label directions. This will ensure both good foliage growth and increased amount and size of flowers. It will also make the plants more resistant to insects and diseases.

Norma writes~ So far I have had no luck with mums. They do not come up the next year. What is the secret to having mums every year without planting them year after year?

A. I will give you some guidelines and hope that one or more will help you. Except for deep freezes where you have not protected them sufficiently or insect damage, there is no reason that they should not come up for at least 4-5 years, and maybe die out after that. Probably one of the most confusing aspects to growing mums is the unexpected sudden death or loss of plants during the winter. There are several strategies that can aid in overwinter survival of garden mums.

First, be sure a hardy variety is selected, preferably one that flowers early and allows sufficient time to acclimate to cold temperatures.

Second, make sure mums are planted in a protected location. Mums do not like sites that are exposed to brutal winter winds. In addition, heavy wet soils in winter can be another hindrance to overwinter survival.

Third, stop fertilizing the plants by the end of July. Fertilizing late in the season often encourages new growth that does not have enough time to acclimate in the fall.

Fourth, leave the old foliage standing.

Lastly, mulch newly planted mums with wood chips, straw or other organic mulches to prevent the plants from lifting out of the soil during the freeze and thaw cycles during the winter.

For best results, transplant mums into well-drained soil; winter injury is most common when mums are planted in poorly drained soils. Potted mums are often grown in a mix that is very high in organic matter. If these are planted in very heavy clay soil without first amending it, the difference between the two soil situations often prevents good root establishment and increases the chance of winter kill. Before planting, make sure there is an adequate amount of organic matter incorporated into the area. After leaves have turned brown, cut back the tops and apply a loose airy mulch several inches thick to allow light to get to the small basal shoots during the winter. The purpose of this mulch is to provide wind protection and keep the soil shaded and froze n so that frost heaving is minimized. Protective mulch may be removed or pulled away from the crown by early to mid-April after danger of severe cold is past.

Assistance from: Missouri Environment and Garden

Q. I have planted some mums in my flower bed. They are growing well [I live in northern California, Sacramento]. Please tell me if I need to protect them in winter and how should I do it. Also, please tell me what other care I should take and how to protect from insects.

A. You can increase the odds of mums surviving the winter by protecting them in the fall. Mulches should be applied in late fall after the plants have been exposed to cold temperatures, typically mid-November. Do not cut chrysanthemums back in the fall. While cutting mums back in the fall is a common practice, recent research found that unpruned plants survived the winter better than those pruned in the fall.

Simply place several inches of mulch around the mums in the fall. Suitable mulching materials include clean, weed-free straw or hay, bark, pine needles and evergreen branches. Leaves are not a good mulch as they tend to mat down and don't provide adequate protection.

They should be planted in early spring after all danger of freezing, however they can be planted almost any time, as long as they have tim e to establish their root system before the hottest weather. They grow best and produce the most flowers if planted in full sunshine, and respond to plentiful food and moisture.

Several diseases and insects attack mums. Prevention of many of them can be done by following these recommendations:

Buy plants that are free of diseases and insects.
Plant in a sunny location.
Allow plenty of air circulation by avoiding over crowding.
Keep your garden free of weeds and disease-infested plants.

Typical problems on mums include verticillium wilt, septoria leaf spot, powdery mildew, rust, blight, aphids, leafhoppers, plant bugs, leafminers, and spider mites. Before using a pesticide, diagnose problems carefully and correctly. The regular use of Chemical Dust that controls most chewing insects, sucking insects, and fungus diseases, will stop damage before it gets started. In cases of bad infestations of disease, remove infected leaves to increase ventilation, water from below only, not allowing the water to get on foliage, and dust with your every two or three days. Check the availability at your local garden center or nursery.

Crissy writes~
I planted some Mums last year and they did not come back this year. Can you please give me some general care tips for Mums. Sun and water requirements? Is there a difference in care if the mums are in containers versus in the ground? And can I take some Mums I have now that are in containers and plant them in the ground this time of year?

A. If you moved your plants outdoors for the summer, it is time to bring them inside. A gradual reintroduction to the indoors is best as sudden changes in temperature, light and humidity can be traumatic to plants resulting in yellowing leaves, leggy growth and possibly dieback. Start bringing plants indoors before night temperatures dip below 45 degrees F (40 to 50 degrees F for tropical) inspecting first for pest problems. To avoid shock, expose plants to reduced lighting gradually. Don't overwater. Repot if necessary. If you want to try to overwinter your mums outside, once plant tops die back after blooming or severe frost, cut the stems even with the ground. Apply a thick layer of straw or bark mulch at the end of October, removing it in the spring as the frost leaves the ground. If we have a mild winter, or you live in a mild location, chances are better that they will survive. September is a good month to landscape with fall mums which are available in a rainbow assortment of colors. Bronze, red, yellow, and white are among the more popular choices. The key to successful planting is proper site preparation. Choose a sunny well-drained spot. Dig and loosen the soil to a depth of 8-10" in a hole twice the diameter of the plant's pot. Mix organic matter such as compost or well-rotted manure into the soil.

Mikki writes~
My sister purchased potted mums around Halloween and doesn't want to plant them because we are going to be moving soon and want to plant them where ever it is we move to. My question is what is the best way to take care of these mums inside this winter? We live in St. Louis and the winters get very bitter. Any advice would be appreciated.

A. If you moved your plants outdoors for the summer, it is time to bring them inside. A gradual reintroduction to the indoors is best as sudden changes in temperature, light and humidity can be traumatic to plants resulting in yellowing leaves, leggy growth and possibly dieback. Start bringing plants indoors before night temperatures dip below 45 degrees F (40 to 50 degrees F for tropical) inspecting first for pest problems. To avoid shock, expose plants to reduced lighting gradually. Don't overwater. Repot if necessary. If you want to try to overwinter your mums outside, once plant tops die back after blooming or severe frost, cut the stems even with the ground. Apply a thick layer of straw or bark mulch at the end of October, removing it in the spring as the frost leaves the ground. If we have a mild winter, or you live in a mild location, chances are better that they will survive. September is a good month to landscape with fall mums which are available in a rainbow assortment of colors. Bronze, red, yellow, and white are among the more popular choices. The key to successful planting is proper site preparation. Choose a sunny well-drained spot. Dig and loosen the soil to a depth of 8-10" in a hole twice the diameter of the plant's pot. Mix organic matter such as compost or well-rotted manure into the soil.