How To Grow Chrysanthemums in Your Garden

Chrysanthemums, otherwise known as mums, are the showstoppers of the fall garden. These vibrant flowers continue to bloom long after other plants have called it quits for the season. As members of the daisy family, mums can thrive as perennials, annuals, or shrubs, making them versatile additions to any garden. This guide will teach you everything you need to know about chrysanthemums, including their varieties and practical tips for growing them at home.

Chrysanthemum Varieties and Classifications

The world of chrysanthemums is vast and diverse, with hundreds of varieties available for any garden style and preference. The chrysanthemum is a member of the Asteraceae family of ornamental flowering plants. This large plant family includes popular blooms such as marigolds, cosmos, zinnias, dahlias, and other daisy-like flowers. Many members of this family exhibit large, ornamental flower heads and dazzling, vivid colors.

Cultivars and Their Significance

When researching chrysanthemums, you’ll often encounter the term “cultivar.” Short for “cultivated varieties,” cultivars are plants that have been selectively bred over time to exhibit specific traits. This process has resulted in an incredible array of chrysanthemum varieties, each with unique colors, shapes, and growth habits. For instance, some cultivars boast intense hues of red, orange, and pink, while others display delicate pastels or multi-colored petals.

National Chrysanthemum Society Classifications

To help organize the multitude of chrysanthemum varieties, the National Chrysanthemum Society (NCS) has grouped mums into 13 distinct categories based on their shape and petal characteristics. While all 13 classes are fascinating, home gardeners typically focus on a few popular types:

1. Decorative: These mums feature flat blooms with shorter petals and a mixture of reflex and incurve florets.
2. Anemone: Characterized by a raised, cushion-like center surrounded by flat petals, these mums are typically larger than four inches wide.
3. Single and Semi-Double: With a daisy-like appearance and a visible center, these mums have one or more rows of ray florets.

Garden Mums vs. Florist Mums

When selecting chrysanthemums for the garden, there’s a big difference between garden mums and florist mums:

• Garden chrysanthemums are hardy perennials that can survive winter in many climates and return year after year with proper care. These varieties are ideal for long-term garden plantings and can become a perennial favorite in the landscape.
• Florist chrysanthemums are typically grown as annuals and are often used for seasonal decorations. While beautiful, these mums are less likely to survive winter outdoors and are best enjoyed as temporary displays. They are usually cultivated in greenhouses, producing the large, showy blooms seen in floral arrangements.

How To Grow Chrysanthemums in Your Garden

Growing chrysanthemums can be a rewarding experience for gardeners of all skill levels. While these flowers are relatively easy to cultivate, understanding their specific needs and preferences can help ensure a successful and vibrant display.

Seeds or Propagation

If you’re eager to grow your flowers from seed and don’t mind the uncertainty, you can plant mums in an outdoor flower bed in the spring. Cover them with mulch, water them regularly, and watch new shoots appear as the season progresses.

Stem cuttings are the most efficient way to propagate new chrysanthemums in your garden. The Missouri Botanical Garden provides step-by-step instructions for cutting mum stems:

• When your chrysanthemums have grown eight to 10 inches tall in the early spring to early summer, you can make stem cuttings. 
• Remove leafy growths, leaving a couple of inches of bare stem at the base of the plant. 
• Plant the stem clipping into a mixture of peat moss, sand, and perlite.
• Water the cutting daily to help it form roots.
• Expose the clipping to early morning sunlight each day, but ensure it doesn’t exceed 75°F.

If you’ve successfully propagated chrysanthemums from seeds or cuttings—or if you have a batch of them from the store—you can also create new growths through root division. Root division involves digging up the root ball of an established mum and cutting it into sections. Once you’ve divided the roots into several sections, you can plant the separate parts to yield new mums.

Choosing the Right Location

Chrysanthemums thrive in full sunlight, requiring six to eight hours of direct light daily for optimal growth and blooming. If full sun isn’t possible, they can tolerate five to six hours of sunlight but may produce fewer flowers. When selecting a spot for mums, consider the following:

• Avoid areas near artificial light sources, such as street lamps or porch lights, as these can disrupt the plant’s natural light response.
• Ensure good air circulation to prevent fungal diseases like powdery mildew.
• Choose a location with well-draining soil to avoid waterlogged roots.

Soil Preparation and Planting

Chrysanthemums prefer nutrient-rich, well-draining soil. Before planting, perform a soil test to determine the pH and nutrient levels. Chrysanthemums prefer slightly acidic to neutral soil (pH 6.5 to 7.0). To create an ideal growing environment:

1. Amend the soil with compost or well-rotted manure to improve fertility and structure.
2. If planting in an area prone to standing water, consider creating a raised bed to improve drainage.
3. Space plants 18 to 24 inches apart to allow for proper air circulation and growth.

Watering and Fertilizing

Proper watering and fertilization are crucial for healthy chrysanthemum growth:

• Water deeply but infrequently, allowing the soil to dry slightly between waterings.
• Apply a balanced, water-soluble fertilizer every two weeks during the growing season.
• Reduce fertilization in late summer to encourage blooming.

Pinching and Pruning

Regular pinching and pruning help promote bushier growth and more abundant blooms. Pinching not only improves the plant’s shape but also stimulates the production of more flower buds, leading to a more spectacular display in autumn.

1. In spring, when plants reach 6 to 8 inches tall, pinch off the growing tips to encourage branching.
2. Continue pinching every two to three weeks until midsummer.
3. Remove faded flowers to promote continued blooming and maintain a tidy appearance.

Staking and Support

Some chrysanthemum varieties, particularly the taller ones, may require staking or support to keep the stems upright and prevent them from flopping over. Using stakes, cages, or other support structures can ensure that the plants remain sturdy and attractive throughout the growing season.

Chrysanthemum Care Through the Seasons

Caring for chrysanthemums requires attention throughout the year. Following a seasonal care schedule can keep your mums healthy and vibrant from one growing season to the next.

Spring Care

As temperatures warm and new growth emerges:

• Remove any winter mulch or protection.
• Divide overgrown plants if necessary.
• Begin fertilizing with a balanced, water-soluble fertilizer.

Dividing crowded chrysanthemums every two to three years will keep the plants healthy and vigorous, encouraging better growth and more blooms.

Summer Maintenance

During the peak growing season:

• Continue regular watering and fertilization.
• Monitor for pests and diseases, treating promptly if issues arise.
• Pinch growing tips to promote bushiness until mid-July.

Maintaining consistent watering practices is essential during the hot summer months to prevent stress on the plants, which can impact their bloom production.

Fall Blooming and Winter Preparation

As days shorten and temperatures cool:

• Reduce watering and stop fertilizing to encourage blooming.
• Protect plants from early frosts with covers if necessary.
• After the first hard frost, cut back stems to 6 to 8 inches above the ground.
• Apply a layer of mulch around the base of the plants for winter protection.

Winter mulch, such as straw or evergreen boughs, will insulate the soil and protect the plants from temperature fluctuations that could damage the plants’ roots.

Common Chrysanthemum Problems and Solutions

While chrysanthemums are generally hardy plants, they can face certain challenges. Being aware of potential issues and knowing how to address them can help gardeners maintain healthy, beautiful mums.

Pest Management

Regularly inspecting plants for signs of pests and taking prompt action can prevent minor problems from escalating into serious infestations. Common pests that affect chrysanthemums include:

• Aphids: Control with insecticidal soap or a strong spray of water.
• Spider mites: Treat with neem oil or introduce predatory mites.
• Leaf miners: Remove affected leaves and use appropriate insecticides if necessary.

Disease Prevention

Practicing good garden hygiene, such as removing plant debris and maintaining proper spacing, can significantly reduce the risk of disease. Chrysanthemums can be susceptible to several diseases:

• Powdery mildew: Improve air circulation and apply fungicides if needed.
• Leaf spot: Remove infected leaves and avoid overhead watering.
• Verticillium wilt: Remove and destroy affected pants, and rotate planting areas.