Tansy in Zone 6B — Southeast

Tansy is a worthwhile addition to any Zone 6B Southeast garden. It's incredibly low-maintenance and its strong scent can help deter pests from your more vulnerable crops. Plus, those bright yellow flowers add a cheerful pop of color to the garden during our long summer.

Even with our hot and humid summers, Tansy is easy to grow if you follow a few simple guidelines. Our long growing season, about 208 days, gives you plenty of time to get it established whether you start indoors or sow directly.

Starting Tansy indoors in the Southeast gives you a head start, but it's not essential given our long growing season. If you want to get a jump on things, start your seeds indoors from early to late February, about six weeks before you plan to transplant.

Use seed trays with a good seed-starting mix. Keep them warm and provide plenty of light – a simple shop light works great. Remember to bottom water your seedlings to avoid damping off, a common problem in our humid spring air. The moderate character of spring here means you shouldn't rush things too early.

Transplant your Tansy seedlings outdoors from late March through mid April, once the risk of frost has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week.

Space them 12-18 inches apart to allow for good air circulation. Be mindful of unexpected temperature swings that can happen in early spring. If a late frost threatens, cover your young plants with a frost blanket.

Direct sowing Tansy is a perfectly viable option here in the Southeast, and honestly, it's the easiest. Sow seeds directly into well-prepared soil from late March through early August. Just be aware that direct-sown plants will mature later than transplants.

Ensure the soil is warm and consistently moist until germination. Lightly rake the soil and scatter the seeds, then gently press them in. Thin seedlings to 12-18 inches apart once they emerge.

Tansy is extremely drought-tolerant and thrives on neglect, which is perfect for our hot and humid summers. In fact, overwatering is more of a problem than underwatering with this plant. Too much water and fertilizer can encourage excessive growth and make it more aggressive.

During the spring and fall, when rainfall is typically more consistent, you likely won't need to water at all unless we're experiencing a dry spell. During the hottest parts of our summer, check the soil moisture using the finger test – stick your finger about 2 inches deep into the soil. If it feels dry, give your plants about an inch of water per week. It's usually best to water at the base of the plant to avoid creating a humid environment around the foliage, which can encourage fungal diseases.

Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to yellowing leaves and root rot. A light layer of mulch, like pine straw or shredded bark, can help retain moisture without suffocating the roots, which is a good idea with our clay soil.

Deadheading is key to managing Tansy's aggressive self-seeding habit. Snip off spent flower heads throughout the season to prevent it from spreading too much. You can deadhead anytime from early June through early November.

In late October, after the first frost, cut the plant back to the ground. This helps tidy up the garden for winter and encourages fresh growth in the spring. Since Tansy is so vigorous, you might also need to consider containing it with barriers to prevent it from taking over your garden beds.

You can expect your first harvest of Tansy from early June through early November, about 75 days after planting. The best sign that your Tansy is ready is when the button-like yellow flowers bloom in midsummer.

Harvest by snipping off stems as needed. Keep harvesting regularly to encourage continued production. As the first frost approaches in late October, you can harvest the remaining foliage to dry for later use as an insect repellent.

Here are two common problems you might encounter with Tansy in the Southeast:

Invasive Tendencies

• What it looks like: Tansy spreads rapidly, popping up in unwanted areas of your garden.
• What causes it: Tansy is a vigorous self-seeder, and the seeds can travel easily. It also spreads by rhizomes.
• How to fix/prevent it: Deadhead spent flowers regularly to prevent seed dispersal. Consider growing Tansy in containers or using barriers to contain its spread. Be vigilant about removing unwanted seedlings.

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).

Southeast Specific Challenges: The hot and humid summers in the Southeast can exacerbate aphid problems and promote rapid spread of Tansy. Regular monitoring and proactive control measures are essential. Also, our wet-summer rainfall can help spread seeds, so deadheading is extra important.

Tansy can be a good companion plant for several crops, especially for deterring pests. It is especially helpful for potatoes, squash, cucumbers, and raspberries.

• Potato: Tansy can help repel potato beetles.
• Squash and Cucumber: Tansy's scent may deter squash bugs and cucumber beetles.
• Raspberry: Tansy can deter raspberry beetles.

Avoid planting Tansy near herbs like basil or mint, as it can inhibit their growth.