How to Grow Hardy Mums for Blooms Year After Year

Hardy mums are herbaceous perennial fall flowers with characteristic daisy-shaped flowers. Unlike florist mums that are grown exclusively for fall flowering and are treated as annuals, hardy mums are winter-hardy in USDA Zones 4 to 9 and provide vivid color year after year. They grow best in full sun, well-drained, slightly acidic soil, and average humidity levels.

Hardy mums are fast-growing and will reach their full height within their first year, with the plant filling out a little more each subsequent year. Hardy mums set buds once the nights become longer and flower in the fall for up to eight weeks. The leaves and flowers of hardy mums are mildly toxic to humans and pets.

Hardy Mum Care

Here are the main care requirements to keep mums healthy.

• Plant mums in full sun in a location protected from damaging strong winds.
• Provide good air circulation around the plants to reduce fungal infections.
• Pinch plants on or around Memorial Day and Fourth of July for best fall performance.
• Water regularly if the plant does not get at least 1 inch of rainwater per week.
• Use a slow-release fertilizer in the spring or a water-soluble plant food monthly.

Light

Hardy mums prefer to grow in full sun, meaning at least six to eight hours of direct sunlight daily. However, in the warmer parts of their growing zones, they benefit from some afternoon shade. The flowers are photoperiodic, meaning they bloom in response to the shorter days and longer nights experienced (in the northern hemisphere) in the late summer and fall.Therefore, don't plant them near street lights or night lights; artificial lighting wreaks havoc with their flowering cycle.

Soil

These plants grow best in organically rich soil with a slightly acidic to neutral soil pH (6.2 to 7.0). Sharp drainage is a must, as soil that remains wet for too long causes root rot.

Water

Mums like consistent moisture but they do not tolerate soggy soil. Water whenever the soil dries out about 1 or 2 inches down. In warmer weather and once the plant is large and in bloom, more frequent waterings will likely be necessary. About 1 inch of water per week is considered a minimum.

Temperature and Humidity

Hardy mums live up to their name; most continue blooming as temperatures dip down as low as 20°F and the roots of most varieties survive winter soil temperatures down to less than 0°F. They also tolerate heat well and withstand temperatures up to 100°F if given ample water. However, excessive humidity encourages fungal diseases, such as leaf spot.

Fertilizer

Mums are fairly heavy feeders. Use a fertilizer that is low in nitrogen and high in potassium, such as 5-10-5. Apply a slow-release fertilizer in the spring or a water-soluble fertilizer monthly but stop in July because any later fertilization triggers tender new growth that is prone to cold damage in the fall.

Types of Hardy Mums

There are numerous types of hardy mums. Based on their flower forms, the plants are divided into 13 different classes. Historically, garden mums were regarded as hardy only to USDA zone 5, but some newer varieties are hardy to zone 4, and some even to zone 3.

• Anemone is a class with long, flat petals on blooms that reach a maximum size of around 4 inches. Varieties include 'Dorothy Mechen' with light purple blooms, 'Samba' with rose-pink flowers, 'Rhumba' with coral red flowers, and 'Harmony' with bright yellow blooms.
• Pompon mums have small, globe-like flowers. They are also known as button mums. Popular varieties include: 'Patriot' with all-white flowers, 'Garnet' with crimson blooms that mature with bronze overtones, and 'Barbara' with small, purple flowers
• Spoon is a class with spoon-shaped petals, this type of mum grows petite flowers up to 4 inches in diameter. Popular varieties include: 'Kimie' with yellow-gold petals, 'Matchsticks' with yellow centers that end dramatically in bright red "spoons," and 'Yellow Quill' with bright yellow centers that fade into creamy white tips
• My Favorite is a newer series with exceptional hardiness to USDA zone 3b. Plants are up to 4 feet tall, with coral, pink, or yellow flowers.
• Morden is another newer series. These jewel-toned mums were bred to be reliably hardy into zone 3. Cultivars include 'Morden Canary', 'Morden Delight', 'Morden Fiesta', and 'Morden Garnet'.

Pruning

To encourage bushy growth and prevent the plant from getting leggy. pinch mums back when the plants are about 6 inches high. Pinch each stem back to about 2 to 3 inches above the base and right above a leaf. Every two to three weeks, pinch back half of any new growth when it reaches 6 inches. Stop pinching around the Fourth of July, or else bud formation won't occur soon enough to ensure flowering in the fall.

After the fall bloom is over and the foliage has died back, you can cut the dead stems back just above the ground or—the recommendation for a northern climate—wait until the spring to cut back the stems because they insulate the roots against the cold.

Propagating Hardy Mums

Hardy mums can be propagated in many ways, but the easiest is by dividing the root clumps in early spring.

Propagating via Division

1. In spring just as new growth is starting to appear, use a shovel to carefully dig up the entire plant, including the crown and the full root clump.
2. Use a sharp knife to cut the clump into sections. Each section should include a healthy group of roots attached to a portion of the crown.
3. Immediately replant the divisions into the desired locations. If planting in groups, space the pieces at least 1 foot apart.

Propagating via Stem Cuttings

1. In late spring or early summer when the initial shoots are 6 to 12 inches long, use sharp pruners to cut off 3- to 4-inch stem tips.
2. Pinch off the lower leaves, then dip the bottoms of the cuttings in rooting hormone.
3. Plant the cuttings in a rooting medium, such as coarse sand or perlite.
4. Keep the cutting moist until roots begin to develop—generally four to five weeks.
5. When a good network of roots has developed and the cutting is showing new leaf growth, carefully transplant the cuttings into the garden or pots filled with standard potting mix.

Potting and Repotting

Use a container with large drainage holes and peat-based potting mix and keep in mind that potted plants need more frequent watering than plants in garden soil.

Repot the plant to a larger pot when it becomes root-bound about every two or three years.

Overwintering

In the landscape, garden mums need no winter protection. However, if you cut back the stems in the fall, apply a thick layer of dry mulch (straw, evergreen branches) over the base to protect the roots from the cold.

Potted plants should be winterized or moved to a cold frame or other sheltered location.

Common Pests & Plant Diseases

Chrysanthemums have a natural resistance to many insects. An entire class of natural pesticides incorporates pyrethrin, which is derived from chrysanthemum flowers. But garden mums are still occasionally the target of small insects, such as aphids, thrips, spider mites, and leaf miners. If leaves show deformity, or if you notice fine webbing or trails on leaves, then using an organic pesticide such as neem oil is a good idea.

Garden mums are susceptible to a variety of diseases, including botrytis (a gray mold disease that causes flowers to shrivel), aster yellows (a viral disease that causes yellowing foliage), and several other fungal diseases such as powdery mildew, verticillium wilt, and leaf spots. It may be worthwhile to use a spray fungicide to treat fungal diseases, but often the best approach is to remove affected plant parts—or even entire plants if the disease is widespread. Avoid overhead watering to help prevent soil-borne diseases from spreading. Fungus only spreads on wet leaves, not dry leaves.

How to Get Hardy Mums to Bloom

Bloom Months

Hardy mums bloom primarily in the fall months but they can start flowering in the late summer.

What Do Hardy Mum Flowers Look and Smell Like?

Hardy mums come in many autumn shades and the plant includes layered, daisy-like petals or tight button-like blooms that have a compact, bushy growth. Hardy mums have a bit of a spicy fragrance with a hint of sweetness.

How to Encourage More Blooms

Hardy mums will usually provide robust blooms if their basic cultural needs are met: plenty of sun and water, and early pinching back of the stem tips.

If you bought potted hardy mums, plant them in the ground after the blooms fade, around late October. Water them well, mulch them, and cut them down to 3 inches from the ground for the winter. Do this with existing mums in the ground after blooming, as well. Protect them during freezes while newly planted mums establish their roots in the ground.

Deadheading Hardy Mum Flowers

In addition to pinching for compact and bushier growth with profuse blooms. spent flowers should be deadheaded to prevent the plant from becoming unkempt and to stimulate continued budding.

Common Problems With Hardy Mums

Garden mums are usually easy to grow provided they are given the right conditions, but they are relatively high-maintenance, so don't be surprised if some problems do arise. This is not a plant-it-and-leave-it specimen.

Yellow Leaves

Yellowing leaves on garden mums often signal a viral or serious fungal disease. The best solution is to cut away all affected plant parts—or even remove and destroy the entire plant before the problem spreads.

Leggy, Droopy Plants

If mums are not severely pinched back as they first begin to grow in the spring, the plants easily develop long, leggy stems that collapse under their own weight. For best results, hardy mums should be pruned or pinched back severely at least twice in spring and early summer before the late summer and fall blooming season gets underway. Pinching back the plants will keep the plants from getting too tall and leggy.

Remember, too, that garden mums need a lot of sun, and if they are planted in shady conditions, the natural tendency will be for the stems to stretch to reach for more sunlight.

Plants Break Off at the Soil Line

It can be tricky to get the watering routine right with these plants. They need regular, reliable watering, but too much water, especially in soil that is too dense or has too much clay, causes root rot that will soften the stems and cause the plants to break off. Make sure to adjust your watering routine based on how much natural rainfall is occurring. More than 1 inch per week might put your plants at risk of root rot.

From: thespruce