Chrysanthemum in Zone 9B — Texas

Chrysanthemums, or mums, are worth growing in Texas for their beautiful fall blooms, when most of your spring and summer flowers are fading in the Texas heat. They add a pop of color to your garden and make stunning bouquets. Plus, the satisfaction of growing your own flowers, especially after battling the unpredictable weather, is hard to beat.

We all know gardening in Texas comes with challenges like extreme heat and unpredictable freezes. But with careful timing, you can absolutely grow beautiful mums. Our long 308-day growing season gives you plenty of opportunity to get them established and enjoy their colorful show.

Starting Chrysanthemum seeds indoors in Texas can be a good option, but it's not always necessary. It's primarily done if you want a specific variety that's not readily available as transplants. If you are going to start seeds indoors, do it in early to late December, about eight weeks before you plan to transplant.

Use seed trays with a good seed-starting mix. Keep them warm and provide plenty of light, either with a grow light or a sunny windowsill. Bottom watering helps prevent damping off, which can be a problem in our early, humid spring conditions. Remember that the early spring warmth often arrives sooner than you expect.

You can transplant your Chrysanthemum seedlings outdoors from early February through early March. This gives them time to establish before the real heat hits.

Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. Space them 12-18 inches apart in a sunny spot. Keep an eye on the weather; those unpredictable freezes can still happen in early February, so be ready to cover them if needed. Buying potted mums in fall, or starts in spring, is often the easier route for most Texas gardeners.

Chrysanthemums need moderate watering, but they definitely aren't drought-tolerant, especially in the Texas heat. Getting the watering right is crucial for healthy growth and abundant blooms.

During the spring and fall, when temperatures are milder, water deeply about 1-2 times a week, providing about 1 inch of water each time. The "finger test" is your friend – stick your finger about 2 inches into the soil. If it feels dry, it's time to water. In the summer, when temperatures are soaring, you might need to water every other day, or even daily, depending on rainfall and humidity.

Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases, especially with our variable humidity. Signs of underwatering include wilting leaves and dry soil. Overwatering can lead to yellowing leaves and root rot. A good layer of mulch, like shredded pine bark, helps retain moisture and regulate soil temperature, which is a big help in our Texas climate.

Pruning your Chrysanthemums is key to getting those full, bushy plants loaded with flowers. The goal is to encourage branching and more blooms.

Pinch off the growing tips of the stems every 2-3 weeks, starting when the plants are about 6 inches tall. Do this through July 4th. This encourages the plant to send out more side shoots, resulting in a bushier plant with more flowering stems. After July 4th, stop pinching. The plant needs time to set its flower buds for fall blooming.

At the end of the season, after the first frost around early December, you can cut the plants back to a few inches above the ground. This helps them conserve energy over the winter and encourages new growth in the spring.

Your Chrysanthemums will typically be ready to harvest from mid April through early June, depending on when you transplanted them and the specific variety. Remember, plant early, harvest early.

The flowers are ready to harvest when they are fully open and the petals are firm. You can cut the stems at an angle, leaving several inches of stem on the plant to encourage more blooms. Chrysanthemums are continuous bloomers, so deadheading spent flowers encourages more production.

As the first frost approaches in early December, you can cut any remaining flowers to bring indoors and enjoy. While the plants themselves are hardy, the flowers won't survive a hard freeze.

Chrysanthemums, like any plant, can have their share of problems, especially in the Texas climate. Here are some common issues and how to deal with 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: Tan, winding trails within the leaves. Leaves may appear distorted or blotchy.
• What causes it: Larvae of small flies that tunnel between the upper and lower leaf surfaces, feeding on the leaf tissue.
• How to fix/prevent it: Remove and destroy infested leaves. Cover plants with 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.

Texas Specific Challenges: The hot-to-extreme heat, variable humidity, and unpredictable rainfall in Texas can all contribute to these problems. The heat can stress plants, making them more susceptible to pests and diseases. High humidity can encourage fungal diseases like rust. Flash floods can waterlog the soil, leading to root rot. And fire ants... well, they're just a constant nuisance we have to deal with!

Chrysanthemums make good companions for several plants in your Texas garden. They can help deter pests and improve the overall health of your garden.

Tomatoes and peppers benefit from having Chrysanthemums nearby because mums help repel certain pests that can attack these vegetables. Lettuce can benefit from the partial shade that taller Chrysanthemums provide, especially during the hottest parts of the day.

There aren't any specific bad companions to avoid, but keep in mind that Chrysanthemums need full sun and good air circulation. Don't plant them too close to anything that will shade them out or restrict airflow, as this can increase the risk of fungal diseases.