Tansy in Zone 10A — Florida

Tansy is a rewarding herb to grow here in Zone 10A Florida, not for the dinner plate, but for its potent insect-repelling properties. Imagine strolling through your garden, relatively bug-free, thanks to this clumping plant. Plus, it's pretty low-maintenance, which is always a win when our summers are so demanding.

Our Florida gardening calendar is different, and summer is often the slow season. But with Tansy, you can plant in fall and harvest well into our mild winters. The 355-day growing season gives you plenty of time to get it established, especially since Tansy is quite hardy once it gets going.

Starting Tansy indoors isn't essential in Florida, but it can give you a head start. If you want to get a jump on the season, aim to sow your seeds indoors from early to late November, about six weeks before you'd like to transplant them.

Use seed trays with a good seed-starting mix, and keep them consistently moist. Bottom watering helps prevent damping-off, which can be a problem with our humidity. Place the trays under grow lights or in a very bright location to ensure strong seedling development. Remember, our spring character is reversed, so getting seedlings going before the coolest months gives them time to mature before our warm season.

Transplanting Tansy outdoors is best done from late December through late January, once the threat of any brief cold snaps has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week.

Choose a sunny to partly shaded spot and space the plants 12-18 inches apart. Our sandy soil benefits from amending with compost to improve drainage and nutrient retention. Keep an eye on the weather; even in late December and January, we can get some unexpected warmth.

Direct sowing Tansy is a perfectly viable option in Florida's Zone 10A, especially given our long growing season. You can direct sow from late December through early October.

Prepare the soil by loosening it and removing any weeds. Ensure the soil temperature is consistently above 60°F for optimal germination. Scatter the seeds lightly over the soil surface and gently press them in. Thin the seedlings to 12-18 inches apart once they emerge. The upside is less work indoors. The downside is you have to protect tiny plants from weather and predators.

Tansy thrives on neglect, which is good news for us Florida gardeners dealing with high humidity and wet summers. Once established, Tansy is very drought-tolerant.

During our cooler, drier months (late fall through early spring), check the soil moisture by sticking your finger about two inches deep. If it feels dry, give the plant a good watering, aiming for about ½ inch of water per week. In our wet summer months, you likely won't need to water at all, unless we're experiencing an unusual dry spell.

Always water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our humid climate. Yellowing leaves can be a sign of overwatering, while wilting leaves indicate underwatering. A layer of mulch can help retain moisture during dry periods and suppress weeds, but don't overdo it, as too much mulch can trap excess moisture.

Pruning Tansy is mostly about keeping it in check and preventing it from becoming too invasive. Deadhead the flowers regularly throughout the growing season to prevent aggressive self-seeding.

Simply snip off the spent flower heads just below the bloom. In late fall, as our first frost approaches (around late December), cut the plant back to about 6 inches to encourage new growth in the spring. Given its vigorous nature, you might need to consider containing it within a raised bed or using barriers to prevent it from spreading too much.

You can expect your first Tansy harvest starting around mid-March and continuing through early January in Zone 10A Florida. Tansy is ready to harvest when it is mature, typically indicated by the button-like yellow flowers that bloom in midsummer.

Cut the stems as needed, using sharp, clean pruners. Harvesting regularly encourages continued production. Remember that Tansy is primarily used as an insect repellent and is not recommended for culinary use due to its potential toxicity in large amounts. As the first frost approaches in late December, you can harvest the remaining foliage for drying and use throughout the winter.

Here are a couple of problems you might encounter with Tansy in Florida, and how to deal with them:

Invasive Tendencies

• What it looks like: Tansy spreads rapidly, popping up in unwanted areas of your garden.
• What causes it: Its vigorous growth habit and prolific self-seeding allow it to quickly colonize new areas, especially in our long growing season.
• How to fix/prevent it: Contain Tansy by planting it in raised beds or using underground barriers. Regularly deadhead flowers to prevent seed dispersal. Remove any unwanted seedlings promptly.

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. Our warm climate favors aphid reproduction.
• 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).

Florida Specific Challenges: Our hot heat, very-high humidity, and wet-summer rainfall can create conditions favorable for fungal diseases and other problems. Good air circulation and avoiding overhead watering are key to keeping your Tansy healthy in our unique climate.

Tansy makes a good companion plant for several garden vegetables and fruits in Florida. It repels many insects, protecting your other crops.

Good companions:

• Potatoes: Tansy deters potato beetles, a common pest in our area.
• Squash & Cucumber: Tansy repels squash bugs and vine borers, which can be problematic in Florida gardens.
• Raspberries: Tansy helps to deter raspberry beetles.

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