Chrysanthemum in Zone 6B — Midwest

Chrysanthemums are worth growing in the Midwest for their vibrant fall colors, providing a burst of beauty when many other plants are fading. Their versatility extends beyond aesthetics; some varieties are edible, adding a unique flavor to salads and teas. Plus, the satisfaction of nurturing these beauties through our sometimes unpredictable Midwest weather is incredibly rewarding.

Our Midwest climate, with its cold winters and variable springs, can present challenges, but with proper timing and care, Chrysanthemums thrive here. Our 183-day growing season gives you ample time to cultivate these lovely flowers, ensuring a stunning display come autumn.

Starting Chrysanthemum seeds indoors isn't always necessary, especially since you can easily find healthy starts at local nurseries each spring. However, if you want to grow a specific variety not readily available, starting indoors gives you that control.

Begin in mid February through early March, about eight weeks before you plan to transplant outdoors. Use seed trays with a good seed-starting mix, ensuring they're kept warm and under grow lights for consistent light. Bottom watering is a great way to keep the soil moist without overwatering the delicate seedlings. Keep in mind that our moderate-to-late springs mean patience is key; don't rush the process.

Transplanting Chrysanthemums outdoors should happen in mid April through mid May, after the threat of a hard frost has passed. Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Midwest weather.

Space your plants 12-18 inches apart in fertile soil and full sun. Keep an eye on the forecast, as we sometimes get unexpected cold snaps in spring. If a late frost is predicted, be prepared to cover your young plants for protection. Alternatively, buying potted mums in the fall or starts in the spring from a local nursery is a great option.

Watering Chrysanthemums correctly is essential in our Midwest climate, which can be both humid and experience summer heat spells. While we get decent rainfall, it's not always consistent. You need to monitor soil moisture regularly.

During the spring, when rainfall is usually more frequent, check the soil using the "finger test" – stick your finger about two inches deep into the soil. If it feels dry, it's time to water. Aim for about one inch of water per week, watering at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our humid conditions. As summer heat spells hit, you might need to increase watering, especially during bud formation.

Signs of underwatering include wilting leaves and dry soil, while yellowing leaves and soggy soil indicate overwatering. A layer of mulch around the base of the plants can help retain moisture and regulate soil temperature, which is especially helpful during summer heat spells.

Pruning Chrysanthemums is key to getting those beautiful, bushy plants loaded with blooms. The method is simple: pinch off the growing tips of the stems every 2-3 weeks, starting in spring and continuing through July 4th.

This encourages the plant to branch out, creating more stems that will produce more flowers. After July 4th, stop pinching; the plant needs time to set its flower buds for fall blooming. When the first frost approaches in mid- October, you can cut back the foliage to tidy up the plant, but leave some growth for potential winter protection.

You can expect your first Chrysanthemum harvest in late June through mid August, depending on the variety and when you transplanted. These are fall-blooming plants, but if you're growing an edible variety you can harvest leaves as they grow.

The best time to cut flowers for bouquets is when they are fully open and the petals are firm. Use clean, sharp scissors to avoid damaging the plant. Cutting the flowers encourages the plant to produce more blooms, so regular harvesting will result in a longer-lasting display. As the first frost approaches in mid- October, harvest any remaining open flowers to enjoy indoors.

Chrysanthemums, like any plant, can face a few common problems in our Midwest gardens. Here's how to identify, fix, and prevent them:

Aphids

• What it looks like: Clusters of tiny soft-bodied insects (green, black, or white) on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth.
• What causes it: Rapid-reproducing sap-sucking insects. Populations explode in warm weather. Ant colonies may farm them for honeydew. Our moderate-to-humid summers can create ideal conditions for aphids.
• How to fix/prevent it: Strong water spray knocks them off. Encourage ladybugs and lacewings (natural predators). Insecticidal soap for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer (it attracts them).

Spider Mites

• What it looks like: Fine stippling on leaves (tiny white dots). Fine webbing on leaf undersides and between stems. Leaves turn bronze or yellow.
• What causes it: Tiny arachnids that thrive in hot, dry conditions. Populations explode in drought stress. While the Midwest isn't typically dry, summer heat spells can stress plants and make them more susceptible.
• How to fix/prevent it: Strong water spray (daily for a week) is the best treatment. Increase humidity around plants. Neem oil or insecticidal soap. Release predatory mites (Phytoseiulus persimilis). Avoid broad-spectrum pesticides that kill predators.

Leaf Miners

• What it looks like: Tan, winding trails or blotches within the leaves. Leaves may appear distorted or prematurely drop.
• What causes it: Larvae of small flies that tunnel between leaf surfaces to feed. Multiple generations can occur throughout the growing season.
• How to fix/prevent it: Remove and destroy affected leaves. Use floating row covers to prevent adult flies from laying eggs. Insecticidal soap or neem oil can help control infestations.

Rust

• What it looks like: Rusty orange, yellow, or brown pustules on leaves and stems, mostly on undersides. Leaves yellow and drop prematurely.
• What causes it: Various rust fungi that spread via wind-borne spores. Favored by warm, humid conditions with moisture on leaves. Our wet-summer rainfall and moderate-to-humid conditions can make this a problem.
• How to fix/prevent it: Remove affected leaves. Avoid overhead watering. Improve air circulation. Apply sulfur or copper fungicide. Don't work among wet plants. Rotate crops.

Midwest Specific Challenges: The moderate-to-hot heat, moderate-to-humid humidity, and wet-summer rainfall of the Midwest can create favorable conditions for fungal diseases like rust and aphid infestations. Regular monitoring, proper watering techniques (avoiding overhead watering), and good air circulation are essential for keeping your Chrysanthemums healthy.

Chrysanthemums make excellent companions for several plants in the Midwest garden. Plant them near tomatoes and peppers; Chrysanthemums help repel harmful insects that might otherwise damage your vegetable crops, and in return, the vegetables won't interfere with their sun and water.

Lettuce also benefits from being planted near Chrysanthemums. The flowers help deter aphids, which can devastate lettuce crops, ensuring a healthier and more productive harvest. Avoid planting near anything that requires very dry soil, as the chrysanthemums need consistent moisture.