Plant Profile: Cascade Mums

Cascade mums grow along a wall in the Japanese Garden of the Missouri Botanical Garden. Photo by Kristina Schall DeYong/Missouri Botanical Garden.

While mums (chrysanthemum) are a popular in the late summer and fall thanks to their ability to withstand temperature changes and their variety of colors, cascade mums can add a whole new layer of creativity and beauty to a garden.

Growing these beautiful blooms does require quite a bit of planning and the right tools, but the results are stunning.

What is a Cascade Mum?

Cascade Mums are displayed in the Pring Dry Garden. Photo by Sundos Schneider/Missouri Botanical Garden.

Simply put, cascade mums are mums.

There’s not a specific species of mums that are naturally cascading. Rather, it’s up to the gardener to train their mums to create that gorgeous waterfall illusion.

Mums themselves have been a favorite of gardeners for over 3,500 years, originating in the far east and carrying an exceptional significance within Japanese culture.

Since the 12th century, a chrysanthemum was the Imperial Seal of the Japan only to be used by the Emperor and his family. This chrysanthemum displays a 16-petalled flower with the tips of 16 additional petals that lie underneath.

Imperial Seal of Japan. Philip Nilsson, Public domain, via Wikimedia Commons.

The Chrysanthemum Throne is also the term for the seat of power in Japan, as well as the physical ceremonial throne that the Emperor sits upon. 

The chrysanthemum‘s popularity reaches beyond the palace walls with many gardens and towns in Japan holding festivals around and including the flowering herbaceous perennial.

How to Grow Cascade Mums

Cascade mums are trained to grow in a cascading fashion in the greenhouse of the Missouri Botanical Garden. Photos by Nathan Kwarta/Missouri Botanical Garden.

As mentioned above, when it comes to cascade mums, it’s more about nurture than nature.

At the Missouri Botanical Garden, our expert horticulturalists grow cascade mums in pots like any other mum, but they attach a flat mesh rack to the pot and orient it at an angle roughly perpendicular to the sun. As the mum grows, the supple new growth is trained with small clips across the mesh, forcing it to grow horizontally at first.

To keep the cascade short, periodically the growth is pinched back so that it does not become too tall. When ready to be displayed, they are placed in baskets and attached to the wall. The growing racks are then bent down so what was growing horizontally is now “cascading” out of the pot like a waterfall.

Our horticulturalist display includes a variety of single stem mums alongside the cascade mums. This selection of plants are chosen for their ability to be trained as a single stem and grow a single large flower. Throughout the growing season they also are pinched back to a single stem and all lateral growth is suppressed. This produces a plant with a single stem and one flower atop.

Below, you can find a helpful guide to what items you’ll need to train your own cascade mums as well as a schedule for raising mums all the way from stem cutting to their full cascading beauty. Learn more about caring for mums on our website.

Large chrysanthemums grow in the Pring Dry Garden. Photo by Kat Niehaus / Missouri Botanical Garden.

What you’ll need to grow cascade mums

  • Snips of stock plants
  • 4-inch pots, 10-inch finishing pots, baskets
  • Scissors
  • Plastic cover
  • Flat mesh rack or wire frame
  • Rooting soil mix of 50% sand and 50% peat
  • Soluble household fertilizer
  • Houseplant mix of peat and perlite

Step-by-step guide to growing cascade mums

  • In early February, snip off 3 to 4-inch long tips of the stems from stock plants and insert 1 to 2 inches of the stem into a rooting soil mix of 50 percent sand and 50 percent peat.
  • For 2 to 3 weeks, keep the cutting continuously moist until the rooting has completed. A plastic cover over the rooting container may prevent the cutting from drying out.
  • For 6 more weeks, transfer the rooted cuttings to 4-inch pots and hold under continuous light. Fertilize on a regular schedule with a soluble household fertilizer. At this time the cuttings should be about 10 to 14 inches tall.
  • Transplant 2 or 3 cuttings to a 10-inch finishing pot with a good houseplant mix of peat and perlite. Immediately give a soft pinch by removing 2 inches of the terminal growth.
  • Keep cuttings under light until mid-April. This is the point in the season that the days are long enough to keep the plants from setting bud.
  • Attach a flat mesh rack to the pot and orient it at an angle roughly perpendicular to the sun. As the mum grows, this will train the supple new growth with small clips across the mesh, forcing it to grow horizontally instead of vertically.
  • To keep the cascade short, periodically pinch back the growth is pinched back so not become too tall. For every 4 inches of growth produced, remove about 2 inches of the stem. Reestablish the terminal shoot by selecting and tying up laterals to the mesh rack.
  • When the frame has become filled, begin to shear the plants by removing all terminal growth and leaving 2 to 3 leaf nodes on each terminal. Stop shearing around July 15th so that the plant will begin to set buds.
  • It takes about 90 more days until the plants will begin to bloom. This means approximately mid-October depending upon the cultivar selection.

Helpful tip: Make your mums bloom earlier by limiting light exposure. The setting and blooming of mums are dictated by light conditions, so reduced amount of sun in the fall triggers hormonal changes in the plant to start producing flowers. This quality can be manipulated to force the plants to produce blooms sooner or later than in natural conditions.

Common Problems & Solutions for Cascade Mums

A number of diseases plague chrysanthemums. Avoiding overcrowded and shaded conditions will help in reducing the incidence of disease because under such conditions, moisture is likely to remain on the leaves providing good conditions for diseases to get started.

Septoria Leaf Spot

Septoria leaf spot disease is caused by a fungus which attacks leaves and produces brown to black spots. The disease will begin on the lower leaves and move its way upward until perhaps half of the leaves become brown and wilted.

The fungus overwinters in debris on the soil surface. Spores produced from infested debris splash onto new foliage in the spring and initiate new infections.

The best way to control the disease is to avoid the initial infections by cleaning up infested debris from around the base of the plant. If the disease shows up on the leaves, a fungicide can be used to avoid continued infections. Fungicides labelled for leaf spot control include benomyl (Benlate), chlorothalonil (Daconil), zineb, maneb or mancozeb. No cultivars are resistant to this disease.

Powdery Mildew

The same fungus which causes powdery mildew on roses, phlox and zinnias can become established on chrysanthemums.

The best conditions for powdery mildew development are moderate to cool temperatures and high relative humidity, but not free moisture on leaves. Typically this disease is more prevalent during the early to late fall when air temperatures at night are relatively cool.

The only way to control powdery mildew is to use a fungicide sprayed every 7 to 10 days. Sulfur, benomyl (Benlate), dinitrophenyl crotonate (Karathane), triademefon (Bayleton) or triflorine (Funginex) are labelled for control of powdery mildew of chrysanthemum.

Virus Diseases

Virus diseases like mosaic and stunt or virus-like diseases such as aster yellows are occasionally a problem on chrysanthemums. These diseases are typically transmitted by insects and vary in their occurrence each year according to the insect survival rate after winter.

They may cause plants to be severely stunted with distorted leaves or have mottled and yellowed leaves with no apparent reduction in growth. Aster yellows is caused by an organism called a mycoplasma which resembles bacteria, but behaves much like a virus in symptom development.

There is little you can do to prevent these diseases and other virus disease in the garden. The best approach to this is to rogue out infected plants as soon as they are discovered and control insects which transmit the viruses; particularly aphids and leafhoppers.

Aphids

Aphids are soft-bodied insects that range in color from green to black and are about one-eighth inch long at the largest. They feed by sucking out plant juices from cells, and most feeding activity will take place from the underside of the leaves and buds.

Under severe infestations, aphid feeding will cause tissues to become yellowed.

The only way to effectively control aphids is with insecticides. Suitable materials include malathion, diazinon and insecticidal soap which when use properly and sprayed to provide uniform coverage can be quite effective.

Caterpillars

A couple different types of caterpillars may chew holes in the leaves or feed on the buds. Generally, these pests will cause little lasting damage and therefore should be tolerated unless the plant shows more than 50% loss of tissue.

Caterpillars can otherwise be controlled by using an insecticide like those mentioned for aphid control. In addition, carbaryl (Sevin) should be added to the list as well as one biological insecticide called Bacillus thuringinesis (Dipel, Thuricide, Bactur). Insecticidal soaps are not effective against caterpillars.

Leafhoppers

These small, wedge-shaped insects are always found on the underside of leaves where they feed by sucking plant juices out of cells. Typically, they are green in color and fly or run sideways when disturbed. Heavy feeding will cause leaves to become mottled, curled and withered.

The same insecticides as those recommended for aphids plus carbaryl (Sevin) will control leafhoppers.

Leafminers

Leafminers spend most of their pest life inside leaves burrowing between the upper and lower cell layers. Light-colored, serpentine mines can be easily distinguished. Heavily infested leaves may curl and wither.

Insecticides sprayed over the surface are not likely to control the feeding of leafminers in the leaves, however, malathion and diazinon can be used to control egg-laying adults.

Plant Bugs

Plant bugs do not typically cause real problem on chrysanthemums, but can be found feeding on sap by
puncturing tissues with their mouth parts. These insects are about one-quarter of an inch long, brown or green in color with some black marking on the back.

If necessary, plant bugs can be controlled by use of malathion, diazinon or carbaryl.

Spider Mites

When conditions become hot and dry, spider mites can be a persistent problem on chrysanthemums.

They are difficult to observe with the naked eye and therefore, often avoid detection until the damage is already done.

These are related, but not true insects which feed on the underside of leaves by rasping and rupturing cells with their mouth parts. The plant sap which leaks out is then lapped up. Heavy feeding will cause the leaves to become bronzed and dry looking.

Insecticidal soaps as well as those pesticides which control aphids can be effective against spider mites. Carbaryl (Sevin) will not control mites.

Where to See Cascade Mums at the Missouri Botanical Garden?

Cascade mums are displayed along a wall in the Japanese Garden. Photo by Kent Burgess/Missouri Botanical Garden.

Our cascade mums will make their seasonal debut within the coming weeks (late September to October).

Our horticulturalists display the cascade mums along the wall of the Pring Dry Garden in the Japanese Garden. The Pring Dry Garden is located on the southwestern side of the Japanese Garden, between the Yatsuhashi zig-zag bridge and the pebbled beach.

The Pring Dry Garden is dedicated to George Pring who worked at the Garden for 63 years while living on campus in a house where the Japanese Garden office is located today. He was renowned for his work in water lily breeding and identification, and he has sometimes been called the father of tropical water lilies.

Enjoy Other Mums at the Garden

While the cascade mums are a site to behold, there are several places throughout the Garden to enjoy bright and colorful mums. Here are a few places to keep an eye out for chrysanthemums outside of the Japanese Garden:

  • The William T. Kemper Center for Home Gardening
  • The Lehmann Rose Garden
  • The Gladney Rose Garden

Photos by Tom Incrocci / Missouri Botanical Garden.


Jessika Eidson

Public Information Officer

Many thanks to Garden horticulturists Heather Moon and Daniel Schachner; Horticulture Manager, Benjamin Chu; Senior Nursery Manager, Derek Lyle; living collection data specialist Brittany Shultz; and ethnobotanist Aurora Prehn for the expert information provided.

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