Chrysanthemum in Zone 7B — Southeast

Chrysanthemums bring a burst of color to your garden just when the summer heat is fading, making them a welcome sight in the Southeast. Their vibrant blooms add beauty to your fall landscape and make for stunning cut flower arrangements. Plus, they're relatively easy to grow, offering a satisfying gardening experience even with our long summer.

Our hot and humid summers can present challenges, but starting your chrysanthemums at the right time and providing proper care will set you up for success. With our long, 235-day growing season, you have plenty of time to nurture these beauties from transplant to bloom.

Starting chrysanthemums from seed indoors is possible, but honestly, most of us here in the Southeast find it easier to buy established plants. However, if you're looking for specific varieties, starting indoors gives you more control.

If you choose to start seeds indoors, do so from mid January through early February, about eight weeks before you plan to transplant. Use seed trays with a good seed-starting mix, and provide warmth and light—a heat mat and grow lights work wonders. Remember to bottom-water your seedlings to avoid damping off, a common problem in our humid climate.

Transplanting chrysanthemums outdoors happens from mid March through mid April, after the last expected frost. Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

Plant your chrysanthemums 12-18 inches apart in well-draining soil. Keep an eye on the weather forecast; those late-season cold snaps can still happen in early spring here, so be ready to cover your young plants if needed.

Watering is key for chrysanthemums, especially during our hot and humid Southeast summers. Aim to provide consistent moisture, but avoid waterlogged soil, which can lead to root rot.

During the hottest part of the summer, you'll likely need to water deeply about 2-3 times a week, providing about an inch of water each time. Use the "finger test" – if the top two inches of soil feel dry, it's time to water. Water at the base of the plant to avoid wetting the foliage, as this can encourage fungal diseases in our humid climate.

In the spring and fall, when temperatures are milder and we often get more rain, you can reduce watering to once or twice a week. Keep an eye out for signs of underwatering (wilting leaves) or overwatering (yellowing leaves). A layer of mulch around your plants will help retain moisture and suppress weeds, but be sure to keep the mulch away from the stems to prevent rot.

Pruning chrysanthemums is essential for encouraging bushier growth and more blooms. You'll want to pinch off the growing tips every 2-3 weeks from when the plants are young until around July 4th.

Pinching encourages the plant to branch out, resulting in a fuller, more floriferous plant. After July 4th, stop pinching to allow the flower buds to develop. As the season winds down and we approach our first frost around early November, remove any dead or diseased foliage to keep your garden tidy.

Chrysanthemums are a fall-blooming flower, so you can expect your first harvest from late May through mid July, depending on the variety and when you transplanted. The flowers last for weeks in the garden, providing a beautiful display.

Cut the flowers for bouquets when they are fully open. Use clean, sharp scissors or pruners to make the cut, and cut the stem at an angle just above a leaf node. This encourages new growth and continued flower production.

As the first frost approaches in early November, you can cut all the remaining flowers to enjoy indoors. Chrysanthemums are continuous bloomers, so regular harvesting encourages more flowers throughout the season.

Chrysanthemums can face a few common problems in our Southeast gardens. Here's how to tackle 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.
• 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.
• 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: Winding, white or yellow trails inside the leaves. Leaves may look blotchy and distorted.
• What causes it: Larvae of small flies that tunnel between the leaf surfaces, feeding on the leaf tissue.
• How to fix/prevent it: Remove and destroy affected leaves. Encourage beneficial insects like parasitic wasps. Use row covers to prevent adult flies from laying eggs. Neem oil can also 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.
• 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.

Southeast Specific Challenges: Our hot, humid summers and frequent afternoon thunderstorms create the perfect environment for fungal diseases like rust. Good air circulation and avoiding overhead watering are crucial. Also, keep an eye out for Japanese beetles, which can skeletonize the leaves. Hand-picking them off the plants in the early morning is often the most effective solution.

Chrysanthemums benefit from companion planting. Plant them near tomatoes and peppers, which attract beneficial insects that can help control pests. Lettuce also makes a good companion, as it provides ground cover that helps retain moisture and suppress weeds, especially useful during our long summers. Avoid planting chrysanthemums near anything that requires consistently wet soil, as they prefer well-drained conditions.