Chrysanthemum in Zone 10B — Florida

Chrysanthemums, or mums, are a fantastic addition to any Florida garden, bringing vibrant color when many other plants are slowing down. The flowers are beautiful in bouquets, and the plants themselves add a cheerful touch to your landscape when the weather starts to cool off. Plus, they're relatively easy to care for if you time things right.

While our Florida gardening calendar is different, with summer being our slow season, mums thrive when planted in fall and harvested in winter. You can absolutely grow these successfully despite our challenges like extreme humidity and sandy soil, as long as you follow the right timeline within our 360-day growing season.

Starting Chrysanthemum seeds indoors isn't always necessary in our zone, since you can often find healthy transplants at local nurseries. However, if you want to grow a specific variety or get a head start, it's definitely doable. Start your seeds indoors from early to late November, about 8 weeks before you plan to transplant them outside.

Use seed trays with a good seed-starting mix, keep them warm, and provide plenty of light – a grow light works great. Bottom watering is a good idea to keep the soil consistently moist without overwatering. Remember, spring is reversed here, so you're starting seeds as other gardeners are winding down.

Transplant your Chrysanthemum seedlings outdoors from early January through early February. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Florida sunshine and temperatures.

Space your plants about 12-18 inches apart to give them room to grow. You'll want to keep an eye on the weather during this time. Even though it's winter, we can still get some warm spells, so make sure to water regularly, especially right after transplanting.

Watering is critical for Chrysanthemums in Florida, especially because of our hot, humid summers. While they need consistent moisture, overwatering can lead to fungal diseases. During the cooler months (late fall through early spring), water deeply about once a week, providing about 1 inch of water.

Stick your finger about 2 inches into the soil – if it feels dry, it's time to water. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal growth in our humid climate. During the wetter summer months, you may not need to water at all, depending on rainfall.

Signs of underwatering include wilting leaves and dry soil. Overwatering can cause yellowing leaves and root rot. Adding a layer of mulch around your plants can help retain moisture and prevent soil from splashing onto the leaves.

Pruning your Chrysanthemums is key to getting bushy plants with lots of flowers. Start pinching off the growing tips every 2-3 weeks, beginning when the plants are about 6 inches tall. Do this through July 4th.

Pinching encourages the plant to branch out, resulting in more blooms. Stop pinching after July 4th to allow the flower buds to develop. As the first frost approaches in late December, you can cut back the plants to a few inches above the ground.

You can expect your first Chrysanthemum harvest from mid-March through early May, depending on the variety and when you transplanted. The flowers last for weeks in the garden, so you'll have plenty of time to enjoy them. Cut the stems for bouquets when the flowers are fully open.

To harvest, use sharp, clean scissors or pruners to cut the stems at an angle. This helps the plant heal quickly and encourages new growth. Cutting flowers regularly encourages the plant to produce more blooms.

As the first frost approaches in late December, consider cutting all the remaining flowers to enjoy indoors before they get damaged by the cold. You can also leave the plants in the ground for next year's blooms.

Chrysanthemums can face a few common problems in Florida, but with the right approach, you can keep them healthy and thriving. Here are some of the most common issues:

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: Visible tunnels or trails inside the leaves. Leaves appear distorted or blotchy.
• What causes it: Larvae of small flies that burrow inside the leaves to feed. Common during warm spells in Florida.
• How to fix/prevent it: Remove and destroy affected leaves. Use 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.
• 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.

Florida Specific Challenges: The extreme humidity and wet-summer rainfall in Florida create ideal conditions for fungal diseases like rust. Regular monitoring, good air circulation, and avoiding overhead watering are crucial for preventing these problems. Nematodes can also be an issue in our sandy soil, so consider using nematode-resistant varieties or amending your soil with organic matter.

Chrysanthemums make good companions for several plants in your Florida garden. Tomatoes and peppers benefit from having mums nearby because the mums can help repel aphids and other pests that often bother these vegetables. Lettuce also appreciates the shade that mums can provide during the warmer parts of the year, preventing bolting.

Avoid planting mums near plants that are highly susceptible to fungal diseases, as the humidity around the mums can sometimes spread these issues.