Tansy in Zone 9A — Texas

Tansy is a great addition to any Texas garden, not for the dinner table, but for its pest-repelling power. Its strong scent helps keep unwanted bugs away from your more delicate plants. Plus, it's incredibly low-maintenance, which is a huge win when dealing with the brutal Texas heat.

We all know the unpredictable weather here can throw a wrench in even the best-laid gardening plans. But with Tansy's hardy nature and our long, 293-day growing season, you've got plenty of time to get it established and thriving.

Starting Tansy indoors is an option, especially if you want a head start. Begin in mid December through early January, about six weeks before our typical transplant window. Use seed trays with a good seed-starting mix, and keep them warm and consistently moist.

Bottom watering is your friend here – set the trays in a shallow dish of water until the top of the soil is moist. You'll also need a grow light, because even though spring comes early in Texas, the daylight hours are still short in December and January.

Transplant your Tansy seedlings outdoors in early February through early March. Before you do, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Texas sun and wind, preventing transplant shock.

Space them 12-18 inches apart in well-draining soil. Keep an eye on the weather forecast – we sometimes get a late freeze, even in Zone 9A, so be ready to cover your seedlings if necessary.

Direct sowing Tansy is easy and often just as successful as starting indoors. Sow seeds directly into the garden from early February through early September. Choose a spot with full sun to partial shade.

Make sure the soil is loose and free of weeds. Lightly cover the seeds with soil and keep them consistently moist until they germinate. Thin seedlings to 12-18 inches apart once they're a few inches tall.

Tansy is incredibly drought-tolerant, which makes it perfect for Texas gardens. Once established, it thrives on neglect. Overwatering is a bigger concern than underwatering with this plant.

During the hottest parts of summer, when temperatures are consistently in the 90s, check the soil moisture using the finger test. Stick your finger about two inches deep into the soil near the base of the plant. If it feels dry, give it a good watering, about an inch of water per week.

Avoid overhead watering, especially when humidity is high, to prevent fungal diseases. Water at the base of the plant. Yellowing leaves are often a sign of overwatering, while wilting can indicate underwatering.

Mulching around your Tansy plants with a layer of native mulch helps retain moisture in the soil and suppress weeds.

Pruning Tansy is all about keeping it under control and encouraging continued growth. Deadhead spent flowers regularly to prevent aggressive self-seeding. If you don't, you'll find Tansy popping up everywhere.

Cut the plants back in the fall, after the first frost around early December, to tidy them up for the winter. Tansy is vigorous, so be prepared to contain it if it starts spreading too much. You might even consider growing it in a large container.

You can expect your first Tansy harvest starting in mid April and continuing through mid December. Tansy is not for culinary use, but it's a great insect repellent.

Harvest the leaves and flowers when the button-like yellow flowers bloom in midsummer. Cut the stems carefully, leaving enough foliage on the plant to ensure continued production. Hang the cuttings to dry for later use as an insect repellent or scatter them around the garden.

As the first frost approaches in early December, harvest any remaining foliage before cutting back the plants for winter.

Here are a couple of common problems you might encounter with Tansy in Texas:

Invasive Spread

• What it looks like: Tansy spreading rapidly beyond its intended area, crowding out other plants.
• What causes it: Tansy is a vigorous self-seeder and can quickly become invasive if not managed. This is especially true in our long growing season.
• How to fix/prevent it: Deadhead spent flowers regularly to prevent seed formation. Consider growing Tansy in containers to limit its spread. If it does start to spread, dig up unwanted plants promptly.

Aphids

• What it looks like: Clusters of tiny (green, black, or white) soft-bodied insects 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: A strong spray of water can knock them off. Encourage beneficial insects like ladybugs and lacewings. Use insecticidal soap for heavy infestations, or neem oil for a systemic approach. Avoid over-fertilizing with nitrogen, as this attracts aphids.

Texas-Specific Challenges: The hot-to-extreme heat and variable humidity can stress Tansy, making it more susceptible to pests and diseases. Unpredictable rainfall can also lead to overwatering issues. Make sure to monitor your plants closely and adjust your watering schedule accordingly. Fire ants can also be a nuisance, so keep them under control to prevent them from disturbing your Tansy plants.

Tansy is a good companion plant for several vegetables and fruits:

• Potatoes: Tansy repels potato beetles, protecting your potato crop.
• Squash and Cucumber: Tansy can help deter squash bugs and cucumber beetles, common pests in Texas gardens.
• Raspberries: Tansy is thought to deter raspberry beetles.

Avoid planting Tansy near cabbage or other brassicas, as it can attract cabbage moths.