Yarrow in Zone 10A — Florida

Yarrow is a fantastic addition to any Florida garden. Its lacy foliage and clusters of vibrant flowers bring beauty and attract beneficial insects. Plus, it's incredibly versatile – use it in dried flower arrangements, as a medicinal herb, or simply enjoy its cheerful presence in your landscape.

Our Florida gardening calendar is different; summer is the slow season. Yarrow thrives despite our humidity and sandy soil, especially when planted at the right time. With a little attention to its needs, you can enjoy its beauty for a long time during our 355-day growing season.

Starting yarrow indoors in Florida offers a head start, but it's not always necessary given our long growing season. If you want blooms the first year, starting indoors can help. Begin late October through mid November, about eight weeks before you plan to transplant.

Use seed trays with a well-draining seed-starting mix. Keep the soil consistently moist by bottom watering to prevent damping off, and provide warmth and plenty of light. A simple shop light works great. Remember, our spring character is reversed, so starting early gives you an edge.

Transplant your yarrow seedlings outdoors late December through late January. This gives them time to establish before the warmer months. Before transplanting, harden off the seedlings by gradually exposing them to outdoor conditions for about a week.

Choose a sunny spot with well-drained soil and space the plants 12-18 inches apart. Keep an eye on the weather; even in late December and January, we can experience temperature swings and even the occasional cold snap. Water thoroughly after transplanting. Since Yarrow is a perennial, buying starts may give you flowers sooner.

Direct sowing yarrow is easy in Florida, thanks to our long growing season. You can direct sow early January through mid October. Prepare the soil by loosening it and removing any weeds. Yarrow isn't picky about soil, but good drainage is essential.

Sow the seeds shallowly and keep the soil moist until they germinate. Once the seedlings emerge, thin them to 12-18 inches apart. Direct sowing is less work than starting indoors, but you might not get blooms in the first year.

Yarrow is drought-tolerant once established, making it perfect for our Florida climate. However, proper watering is still essential, especially when plants are young. During the cooler months, water only when the top two inches of soil feel dry to the touch – use the finger test.

In the summer, when the heat and humidity are high, you might need to water once or twice a week, depending on rainfall. Aim for about an inch of water per week. Water at the base of the plant to avoid wetting the foliage, as our high humidity can encourage fungal diseases.

Signs of underwatering include wilting and dry, crispy leaves. Overwatering, on the other hand, can lead to floppy growth and root rot. Mulching around the base of the plant with pine straw or wood chips helps retain moisture and suppress weeds.

Pruning yarrow keeps it tidy and encourages more blooms. Deadhead spent flowers regularly throughout the growing season to promote a second flush of blooms. Simply snip off the flower heads just below the lowest petals.

In the fall, after the first frost around late December, cut the plant back to its basal foliage. This helps it conserve energy over the winter and encourages fresh growth in the spring. Yarrow can be aggressive, so divide the clumps every 2-3 years to keep it in check.

You can expect your first yarrow harvest mid March through early January, about 65 days after planting. Harvest the flowers for drying when they are fully open and the colors are vibrant. These make excellent dried flowers.

Cut the stems just above a leaf node to encourage new growth. Harvest in the morning after the dew has dried. To dry the flowers, hang them upside down in a cool, dark, well-ventilated place.

Yarrow is a continuous harvest plant, so you can keep harvesting flowers throughout the growing season. As the first frost approaches in late December, you can harvest any remaining flowers to dry and enjoy throughout the winter.

Yarrow is generally easy to grow, but here are a few problems you might encounter in Florida:

Aggressive Spreading:

• What it looks like: Yarrow spreads quickly via rhizomes, potentially taking over garden beds.
• What causes it: Its vigorous growth habit, particularly in our long growing season.
• How to fix/prevent it: Plant in containers to restrict growth, or divide regularly. Remove unwanted offshoots promptly.

Powdery Mildew:

• What it looks like: White or grayish powdery coating on leaves and stems. Leaves may curl, yellow, and die.
• What causes it: Fungal disease thrives in warm days, cool nights, and moderate humidity. Dry leaf surfaces favor it. Our very-high humidity can make this even worse.
• How to fix/prevent it: Improve air circulation by spacing plants adequately. Remove affected leaves. Neem oil or potassium bicarbonate sprays help. Milk spray (1 part milk to 9 parts water) can also be effective.

Aphids:

• What it looks like: Clusters of tiny green, black, or white insects on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth.
• What causes it: Rapidly reproducing sap-sucking insects that thrive in warm weather. Ant colonies may farm them.
• How to fix/prevent it: Strong water spray to knock them off. Encourage ladybugs and lacewings (natural predators). Insecticidal soap for heavy infestations. Avoid excess nitrogen fertilizer.

Florida Specific Challenges: Our hot, humid summers and wet-summer rainfall can exacerbate fungal problems like powdery mildew. Ensure good air circulation and avoid overhead watering. While Yarrow is drought-tolerant, be mindful of consistent moisture during establishment.

Yarrow makes a great companion plant in the Florida garden. Plant it near tomatoes and peppers to attract beneficial insects like ladybugs and lacewings, which prey on aphids and other pests. Yarrow also benefits herbs, enhancing their essential oil production.

It's also a good companion for strawberries, as it attracts pollinators and helps deter pests. Avoid planting yarrow near plants in the Allium family (onions, garlic, chives), as it can inhibit their growth.