Tansy in Zone 6A — Great Plains

Tansy is a classic, hardy perennial that pulls its weight in a Great Plains garden. It's not for eating, but its strong scent makes it a fantastic natural insect repellent. Plus, those cheerful yellow button flowers add a splash of color to your landscape even in the face of our extreme weather.

Growing anything in the Plains comes with challenges: wind, drought, and hail are always a possibility. But don't let that scare you off. With a little planning and the right timing, you can absolutely grow Tansy successfully within our 188-day growing season.

Starting Tansy indoors isn't essential, as it direct sows easily, but it can give you a head start, especially if you're further north in our zone. If you want to go this route, sow seeds mid-February through early March, about six weeks before you plan to transplant.

Use seed trays with a good seed-starting mix and keep them in a warm spot with plenty of light – a south-facing window or under grow lights works well. Don't forget to water from the bottom to avoid damping off. Be ready for variable spring conditions when it's time to transplant.

Transplant your Tansy seedlings outdoors early to late April, once the danger of hard frost has passed. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to our Plains winds and temperature swings.

Space your Tansy plants 12-18 inches apart in a sunny spot with well-drained soil. Keep an eye on the forecast – a late frost or sudden cold snap can still happen in April, so be prepared to cover your young plants if needed.

Direct sowing Tansy is a straightforward method that suits our prairie soil. Sow seeds early April through late July, after the soil has warmed up a bit. Tansy isn't too fussy, but a little compost worked into the soil before sowing will help.

Simply scatter the seeds lightly over the soil surface and gently press them in. Keep the soil consistently moist until the seedlings emerge. Thin the seedlings to 12-18 inches apart once they're a few inches tall. Direct sowing is a great option if you have a large area to cover or prefer a more naturalized look.

Tansy is incredibly drought-tolerant and thrives on neglect, making it perfect for our variable Plains rainfall. Overwatering is a far bigger risk than underwatering.

During the spring, when temperatures are cooler and rainfall is more frequent, you likely won't need to water established Tansy at all unless we're in a particularly dry spell. In the heat of summer (93°F is typical), give your Tansy a good soak only when the top two inches of soil feel dry to the touch – use the finger test. An inch of water per week is plenty, if even needed.

Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases, especially with our low-to-moderate humidity. Yellowing leaves are a sign of overwatering, while drooping leaves can indicate underwatering, though Tansy will usually bounce back quickly after a drink. Mulching around the base of the plants with straw or wood chips helps retain moisture and suppress weeds, also reducing the need for frequent watering.

Deadheading Tansy is key to preventing it from becoming too aggressive in your garden. Remove the spent flower heads regularly throughout the summer to prevent self-seeding.

In late fall, after the first frost around mid- October, cut the plants back to the ground. This tidies up the garden and prepares the plants for winter. Leave some foliage standing if you want to provide winter interest or habitat for beneficial insects.

You can start harvesting Tansy as soon as the plants are established, typically mid June through late October in our region. The best time to harvest is when the button-like yellow flowers are in full bloom, as this is when the scent is strongest.

Simply cut the stems near the base of the plant, taking care not to damage the surrounding foliage. Tansy doesn't "ripen" like a fruit, so you can harvest it continuously throughout the growing season. As the first frost approaches in mid- October, gather any remaining foliage for drying or other uses. Remember, Tansy is not for culinary use and can be toxic in large amounts.

Tansy is a pretty tough plant, but here are a couple of problems you might encounter in the Great Plains:

Invasive Tendencies

• What it looks like: Tansy spreads rapidly, both by seed and rhizomes, quickly taking over garden beds and crowding out other plants.
• What causes it: Tansy is a vigorous grower and self-seeds readily. Our fertile prairie soil and long growing season (for a perennial) provide ideal conditions for it to spread.
• How to fix/prevent it: Contain Tansy by planting it in a raised bed or using barriers sunk deep into the soil to prevent rhizome spread. Deadhead regularly to prevent seeding. Be vigilant about removing unwanted seedlings.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. Sticky honeydew residue and curled or distorted new growth.
• What causes it: Rapid-reproducing sap-sucking insects that thrive in warm weather. Ant colonies may farm them for honeydew.
• How to fix/prevent it: A strong spray of water from the hose can knock them off. Encourage natural predators like ladybugs and lacewings. Use insecticidal soap for heavy infestations or neem oil for a systemic approach. Avoid excess nitrogen fertilizer, as it attracts aphids.

Great Plains Specific Challenges: Our hot summers and variable rainfall can stress Tansy, making it more susceptible to aphids if not properly watered. But overall, its drought tolerance makes it a reliable and low-maintenance addition to the Plains garden.

Tansy makes a good companion plant in many gardens, particularly in the Great Plains. Its strong scent repels many common pests, benefiting nearby plants.

Good companions include potatoes, squash, and cucumbers. Tansy can deter potato beetles, squash bugs, and cucumber beetles, reducing the need for pesticides. It's also said to help raspberries by deterring certain insects that can damage the canes.

Avoid planting Tansy near members of the cabbage family, such as broccoli and cauliflower, as it may inhibit their growth.