Chrysanthemum in Zone 7B — Texas

Chrysanthemums are a fall-blooming favorite for good reason. Their vibrant colors bring life to the garden when many other plants are fading, and they make fantastic cut flowers that last for weeks. Here in Texas, they provide a burst of color after the brutal Texas heat of summer starts to ease off, making them a welcome addition to any landscape.

While our unpredictable weather can be a challenge, the long 255-day growing season gives you plenty of time to get chrysanthemums established and blooming beautifully. By starting early and paying attention to their needs, you can enjoy these cheerful flowers even with our Zone 7B weather.

Starting chrysanthemums from seed indoors isn't the most common method, since they're readily available as starts in the spring and established plants in the fall, but it’s definitely an option if you have a specific variety in mind that you can't find locally. If you're going to give it a try, start your seeds indoors in early to late January, about 8 weeks before you plan to transplant them outdoors.

Use seed trays with a good seed-starting mix, and keep them warm – around 70-75°F – until germination. A heat mat can be helpful here. Provide plenty of light; a grow light is ideal. Water from the bottom to avoid damping off. Given our early springs here in Texas, it's important to keep an eye on the weather forecast and be ready to adjust your transplanting schedule if we get an unexpected warm spell.

Transplant your chrysanthemum seedlings outdoors in early March through early April, after the last expected frost. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Texas elements and reduces transplant shock.

Space them 12-18 inches apart in a sunny spot with well-draining soil. At transplant time, keep an eye on the weather forecast. We can get some late freezes, so be prepared to cover your new transplants if necessary. You can also just buy potted mums in the fall, or starts in the spring if you're not up for starting from seed.

Chrysanthemums need consistent moisture, especially during bud formation, but they don’t like to be waterlogged. Here in Texas, that means paying close attention to your watering schedule, which will vary depending on the season and our unpredictable rainfall. During the spring and fall, when temperatures are milder, water deeply once or twice a week, providing about 1 inch of water each time.

The "finger test" is your best friend: stick your finger about 2 inches into the soil. If it feels dry, it's time to water. During the brutal Texas heat of summer, you may need to water more frequently, possibly every other day, especially if the humidity is low. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in 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 hardwood, will help retain moisture in the soil and keep the roots cool during the hottest months, which also helps to suppress weeds and conserve water.

Pinching your chrysanthemums is key to getting a bushier plant with more blooms. Starting in the spring, pinch off the growing tips of the stems every 2-3 weeks. This encourages the plant to branch out and produce more flowering stems.

Stop pinching around July 4th. After that date, the plant needs to focus on bud formation for the fall bloom. After the first frost around mid- November, cut back the dead foliage to the ground to help prevent disease and tidy up the garden.

Chrysanthemums are fall-blooming plants, so you can expect your first harvest of flowers from mid May through early July, depending on the variety and when you planted them. The flowers last for weeks in the garden, providing a long-lasting display of color.

Cut the flowers for bouquets when they are fully open. Use sharp, clean snips to make the cut, and cut the stem at an angle just above a leaf node. Removing spent flowers (deadheading) will encourage the plant to produce more blooms. As the first frost approaches in mid- November, you can cut any remaining flowers to bring indoors and enjoy, but don't expect them to ripen further.

Chrysanthemums can face a few common problems, especially in our Texas climate. Here's how to identify and address 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:* White or yellow squiggly lines or blotches on leaves. Tunnels visible within the leaf tissue. *What causes it:* Larvae of small flies that burrow between the leaf surfaces to feed. *How to fix/prevent it:* Remove and destroy affected leaves promptly. Cover plants with lightweight 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 create ideal conditions for pests and diseases to thrive. Monitor your plants regularly and take action quickly to prevent problems from getting out of control. Ensure good air circulation to prevent fungal diseases.

Chrysanthemums benefit from companion planting, and here in Texas, there are a few good options to consider. Tomatoes and peppers make good companions because they deter some common pests that affect chrysanthemums. Plus, they enjoy similar growing conditions, so they'll thrive in the same sunny spot with well-drained soil.

Lettuce is another good companion because it provides ground cover, which helps to keep the soil cool and moist, which is especially important during the hot Texas summers. Avoid planting chrysanthemums near plants that are susceptible to the same pests and diseases, as this can increase the risk of problems.