The Ultimate Guide to Fall Garden Mums
Updated: Apr 20, 2019
“If you would be happy for a lifetime, grow Chrysanthemums.” - Chinese Proverb
Garden mums (Chrysanthemum) are readily available in a wide range of colors for adding late season color to your garden or your front porch. With a little understanding and some simple tips, you can have a lush, beautiful garden mum display to help celebrate the changing of seasons.
The most common question we get asked about mums is if they are annuals or perennials. The answer is both. There are several species of chrysanthemums, with some being hardier than others. The mums we grow at our farm are perennial, garden-hardy mums selected for our growing zone here in Central Illinois. Because our mums are locally grown at our farm, they are healthy, strong, and acclimated to our climate when they leave our farm in the fall. There is no guarantee that the mums you purchase at our farm will come back the next year when they are planted in the fall. It all depends on how well they are cared for and when and where they are planted after they leave our farm. Whether you want to enjoy fall mums on your porch or plant in your garden, we've included everything you need to know in this guide for helping you with your green-thumb skills.
In late summer when other plants call it quits, mums hit their stride. Like poinsettias, they're photoperiodic, meaning they rely on specific amounts of light to send the signal that it's time to start putting on a show. Garden mums are short-day plants and initiate flower buds in response to an interaction of day length, temperature and plant age. On average, garden mums will not start to set buds until the nights last about 10 hours long. Blooms follow in six to ten weeks.
Different mum varieties will come into flower at different times in fall, based primarily on their responses to day length. Early season varieties can be expected to come into flower in early to mid-September, mid-season varieties from middle to late September, late season varieties from late September to early October.
The best stage to purchase a garden mum is when the buds are just beginning to break open. Mums with fully open flowers are okay to buy, but be aware that they will not last as long in your garden or on your porch. Depending on weather conditions and mum varieties, you can expect to get a good display of color for four to six weeks once buds begin to break open. Extended periods of hot weather will age the flowers more quickly. If you plan to place mums in a shaded garden site, then it will be best to purchase mums with flowers that are more open, as mums that are in tight bud may not open properly when in the shade.
Most gardeners plant mums too late in the fall for the plants to survive over winter. Some of the mums may come back the next year if they are mulched for the winter. The shallow-rooted mums that are planted late in fall while in full bud or flower just do not have enough time to establish before winter sets in. We break down all the factors to consider when caring for and planting fall mums later in this guide.
The Chrysanthemum is one of the most popular flowers in the world, next only to the rose. The name "chrysanthemum" is derived from the ancient Greek words chrysos, meaning gold with anthemon, meaning flower. Chrysanthemums were cultivated in China as early as 15th century BC. The plants were used as herbs and the roots and leaves were eaten. The Chrysanthemum was brought to Japan by Buddhist monks in 400 AD. Japanese emperors loved the Chrysanthemum flower that they sat upon Chrysanthemum thrones. Chrysanthemums - kikus in Japanese - were featured on the Imperial Crest of Japan. Mums were introduced into the United States in 1798 when Colonel John Stevens imported a cultivated variety known as 'Dark Purple' from England. Today, the plant is the quintessential autumn flower used for decorating, gardening, and as a gift plant.
Chrysanthemums are more than just a pretty face. The Chinese believe this flower represents ease and rest, and often use it as an object of meditation; and the Japanese consider it to be a symbol for life and happiness. Mum plants have also been shown to reduce indoor air pollution by the NASA Clean Air Study.
The chrysanthemum has its own traditional holiday, Chrysanthemum Day. This Japanese holiday is celebrated on September 9 - the 9th day of the 9th month - in locations throughout Japan, Korea, and Okinawa by viewing chrysanthemum displays, eating chrysanthemum cakes (a dumpling made from yellow petals mixed with rice flower) and drinking chrysanthemum wine.
Botanical Name: Chrysanthemum
Common Name: Garden mums, garden chrysanthemums, fall mums, hardy mums
Plant Type: Herbaceous perennial flower
Mature Size: 4 to 36 inches tall, 12 to 36 inches wide; size varies depending on variety.
Sun Exposure: Full sun
Soil Type: Humusy, fertile soil that is moist but well-drained
Soil pH: 6.5 to 6.7
Bloom Time: Late August to frost
Flower Color: Various shades of yellow, white, red, orange, purple, and bi-colors
Hardiness Zones: 3 to 9
Native Area: Native to Asia and northeast Europe; most species come from eastern Asia.
Types of Chrysanthemum
There are thousands of varieties of floral and garden mums. The varieties can differ in size, colors and number of flowers per stem. The National Chrysanthemum Society (U.S.A.) classifies mums into 13 groups based on the forms of their blooms and florets:
Class 1: Irregular incurve
Class 2: Reflex
Class 3: Regular incurve
Class 4: Decorative
Class 5: Intermediate incurve
Class 6: Pompom
Class 7: Single and semi-double
Class 8: Anemone
Class 9: Spoon
Class 10: Quill
Class 11: Spider
Class 12: Brush and thistle
Class 13: Unclassified types
For detailed descriptions of these National Chrysanthemum Society classifications, visit Chrysanthemum Classes.
The November birth flower
The 13th wedding anniversary flower
National flower of Japan
The official flower of Chicago, IL and Salinas, CA
A popular Mother’s Day gift in Australia (May is in autumn)
The official flower of November in the U.S.
Used in teas to detox and treat the flu and headaches in some parts of Asia
Known to bring happiness and laughter in the home according to Feng Shui
The largest commercially grown plant in the U.S.
So what makes mums so special? Maybe it’s because they are so versatile and come in virtually every color on the spectrum. Maybe it’s because they are deep rooted in history and carry much significance. Or maybe it’s because they are simply a beautiful flower. Either way, there is more to these autumn enchanters than meets the eye.
Caring for Potted Mums
Mums are generally considered low maintenance plants. Knowing how to care for mums properly simply requires basic gardening techniques. With just a little special care, your mums will be filled with a multitude of beautiful blooms.
To Re-Pot or Not
Our fall mums are grown in 9" or 12" pots at our farm. Many of our customers choose to leave their mums in the original pots. Be sure to check soil moisture daily and water mums when the top 1 inch of soil begins to dry.
Re-potting your mum can increase its longevity by expanding room for the plants roots. To re-pot, choose a container that is a little bigger than the original container. Fill the bottom of the new pot with a good quality potting soil. Break up any roots you can, but do not damage the roots.
When you put the plant in the new pot, the surface of the soil should be an inch below the lip of the new pot. Make sure you have soil, not air surrounding the roots. Tamp down soil gently. Give the pot a good watering until it flows out of the bottom of the pot.
Water, But Not Too Much
How often and how much water you give a mum can mean the matter of LIFE OR DEATH! Okay that sounds a little drastic, but it's the truth. When their leaves are drooping, which can happen ridiculously quickly, is an indicator of a watering issue. This is the leading cause of premature mum deaths.
If the weather has been hot for a period of time, test the soil by sticking your finger, up to the second knuckle into the soil to see if it feels dry. If it is dry, water your mum. The hotter and drier the weather, the more you will need to water. On the other hand, you can also over water your mum. If the leaves of your mum are drooping and the soil is wet when sticking your finger in the soil, then you are over watering it. During periods of rainy or cool weather, you will want to cut back to every other day when watering your mum, especially if the soil feels wet.
Deadheading is easy, but one of those tedious garden chores that almost as soon as you finish it, you have to start over again. When blooms begin to brown, just pluck them off to make room for additional buds waiting for light and room to break open. Your mums will look much better when finished and will bloom much longer!
Planting Fall Mums
Since mums bloom late in the season, they are nondescript, though not unattractive, in the border until blooming time. They are best planted next to early bloomers. As these spring blooming flowers fade, the mums will fill in and hide their unattractive fading foliage.
Mums make a wonderful impact in containers, but when planted in mixed borders, they will end your garden season with a bang when paired with other late season bloomers such as sedum, goldenrod, Russian sage, asters, gaillardia and the changing foliage of ornamental grasses.
For mums to be truly hardy, they need time to become established in the ground. Ideally, they are best planted in the spring and allowed to grow in place all season. When planting mums in the fall, it is best to plant them before they start flowering in late August or early September. Planting them before or during bud stage ensures that their energy is not completely going to their flowers yet.
When planting your mums, also consider planting them in a somewhat protected location where they will not be exposed to winter winds that can decrease their chances of surviving the winter.
Chrysanthemums are sun-loving plants. Although they technically require only 6 hours of sunlight each day, the more light they receive, the better their growth, bloom and hardiness.
Mums bloom due to their photoperiodic nature which means they bloom in response to the shorter days and longer nights. When the plant senses a change in the length of darkness in late summer, it begins to set buds. Planting near artificial lights, such as security lights or porch lights, can alter the bloom time of your mums.
Mums can survive in most soils, but they thrive in well-draining soil with consistent moisture. Growing mums in hard, dry soil prevents the roots from becoming well established, while wet, boggy soil drowns the roots. Finding the middle ground is key.
If you’ve planted other perennials, then you already know how to plant mums. To create a good soil for your mums, work your soil to a depth of 8 to 12 inches. Mix in 2 to 4 inches of organic material, such as compost or peat moss. The perfect soil texture can be tested by taking a handful and squeezing. When you open your hand, the soil shouldn’t clump or quickly fall apart. It should simply crumble. Mums like a soil pH slightly on the acidic side.
Spacing It can be tempting to plant mums closely together. Planted mums will reach up to 3 feet in height and width. Like many perennials, mums will often become larger each year. Even if your flower bed looks a bit bare when you first plant your mums, in time it will fill in.
Spacing mums properly is essential for plant health. Plants that are too crowded compete for nutrients, have root system issues, attract pests and suffer from disease.
Watering Planted Mums
It is very important that mums establish a good root system. The deeper the roots, the more likely the plant will survive very hard freezes and even drought conditions. To encourage deep root growth, water your soil so that it is wet down to a depth of 6 to 8 inches. Mums do not like to get dry. Insert a stick into the soil and see if it is damp at that depth. Soil should remain moist, but not soggy. Soggy soil can cause root rot and other diseases. It can be difficult for a mum to bounce back once it has been over watered.
Once the ground cools, stop watering your mums. This can be anywhere from late September to early October. Cover the soil around your plants with a 2- or 3-inch layer of mulch. This will help the soil retain moisture without it becoming very saturated. It will also protect the plant's roots from hard winter freezes.
Temperature and Humidity
If have high temperatures occur, particularly at nighttime, it can cause the plant to flower later than it normally would. Heat delay can cause irregularly formed flower buds, erratic flowering, deformation of the plant’s crown and other developmental issues.
Cool temperatures don't bother mums. In fact, chilly weather intensifies colors and keeps blossoms looking fresh until a hard, killing frost drops the curtain on the gardening year. I
Tuck Them in for Winter
As one of their nicknames "hardy mums" suggests, they can handle cool temperatures. The key to winter survival is a consistent soil temperature. Frequent freezing and thawing cycles damage the roots and confuse the plant. Adding a thick layer of mulch can help maintain an even soil temperature throughout winter by providing extra plant protection.
First, leave the foliage on the plants until spring. Do not prune them back after frost has turned them brown. Research reveals that allowing it to die back naturally over the winter produces a stronger plant. Simply clean up the dead stems and foliage in the spring.
Spread at least 4 to 6 inches of mulch under your mums as soon as the surface of your soil begins to harden and the thermostat begins to dip into the 20s. Using a loose mulch, like straw, can reduce compaction and increase the insulation of the ground. Covering mums with buckets or a styrofoam cones will provide added-protection from winter winds. If covering mums with a styrofoam cone, we recommended putting a few small to medium size holes in the top of the cone to prevent overheating your mum during warmer days.
It is important to provide nitrogen and potassium to mums during their vegetative phase. Feed the plants before flower buds form to promote healthy roots, bud development, and a vigorous plant. Start a feeding cycle in April or May. You can get a time-released fertilizer (12-6-6), which feeds the plants for about three months. With this fertilizer, you might only need to feed the plants once. The general rule of thumb is to begin after all danger of frost has passed. That way any new growth forced by the nutrients will not be in danger of damage from icy weather. Established plants should not be fed after July, so new growth is not injured by frost.
Pruning for Fall Blooms
Mums sprout in early spring and then start to grow in a bush-like fashion, sometimes. But, depending on weather and the environment, if left to grow naturally without any pinching or pruning, some varieties will start blooming in the summer and grow quite tall and leggy.
This being said, you don't have to pinch or prune mums if you don't mind them blooming during the summer months.
If you want fall flowers on your mums, you will need to trim the plants back periodically throughout the summer. Start when the plants are about 4 to 5 inches tall and repeat every 2 to 3 weeks until about mid-July. This will cause the plant to get stocky and bushier, and by late summer, it should be covered with flower buds.
Do not prune mums after they have finished blooming in the fall. Leave all dead foliage and stems on for the winter.
Dividing Established Mums
Like many other perennials, mums benefit from dividing every three to four years. You may notice your mums begin to look thin in the centers and oddly shaped. Over time, the center roots of the plant may become old and woody, while the outside roots are younger and healthier. If you notice your mums no longer grow full and round, they may simply need to be divided. Younger plants will not have a sufficient root system to survive.
Spring is the best time to divide your mums. Pick plants that are at least 6 inches tall. Gently remove the plant from the ground and break it up into smaller sections. Be careful to not damage the roots. You can discard the woody center of the plant, since it won’t perform as well as the younger, outer sections. Replant at least 18 inches apart in garden soil rich with organic matter.
Common Pests and Diseases
Mums contain a natural substance called pyrethrin, which helps repel most insects. Mums can still suffer damage from aphids, thrips, and spider mites. Common diseases include botrytis, leaf spots, rust, powdery mildew, stem and root rots, verticillium wilt, aster yellows, and viruses. Leaf spots and powdery mildew are rarely fatal, but plants with other diseases should be removed and destroyed.
There are many reasons to welcome this enchanting flower into your home for fall. It’s not only a beautiful autumn flower; it has a rich history, healing abilities and is also tasty. Fill your home, garden, or your front porch with vibrant fall bouquets, abundant with the perfect fall flower - the chrysanthemum.
Have questions? Send them to firstname.lastname@example.org and we’ll do our best to help you with your gardening success.
Greg & Mariah Anderson