Yarrow in Zone 5B — Mid-Atlantic

Yarrow is a fantastic addition to any Mid-Atlantic garden. Its feathery foliage and clusters of blooms bring beauty, attract beneficial insects, and make excellent dried flowers. Plus, it's surprisingly easy to grow here with our four distinct seasons.

Our humid summers and variable spring weather can sometimes present challenges, but with proper timing and care, Yarrow thrives in our 178-day growing season. You'll find it a rewarding and low-maintenance addition to your landscape.

Starting Yarrow indoors in the Mid-Atlantic gives you a head start, but it's not always necessary. If you want blooms the first year, especially from seed, it's a good idea. Start your seeds indoors from early to late February, about 8 weeks before you plan to transplant.

Use seed trays with a good seed-starting mix, and keep them warm (around 70°F) and well-lit. Bottom watering is key to prevent damping off – set the tray in a shallow dish of water and let the soil soak it up. Our moderate spring means you can get away with direct sowing too, but indoor starting gives you more control.

Transplant your Yarrow seedlings outdoors from early April through early May, once the danger of hard frost has passed. Before planting, be sure to harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Mid-Atlantic's variable spring weather.

Space your plants 12-18 inches apart. Remember that Yarrow is a perennial, so choose your location carefully! Buying starts can give you blooms the first year.

Direct sowing Yarrow is a perfectly viable option in the Mid-Atlantic. Sow your seeds directly into the garden from mid April through late July. This gives the seeds plenty of time to germinate and establish before our first frost, typically around mid- October.

Prepare the soil by loosening it and removing any weeds. Yarrow prefers well-drained soil, so amend with compost if you have heavy clay. Keep the soil consistently moist until the seedlings emerge. Thin them to 12-18 inches apart.

Yarrow is wonderfully drought-tolerant once established, which is great for our humid summers. However, young plants need consistent moisture to get started. During the first few weeks after planting, water deeply whenever the top inch or two of soil feels dry.

After that, let the soil dry out more between waterings. Stick your finger about 2 inches into the soil – if it feels dry, it's time to water. In general, mature Yarrow needs about an inch of water per week, including rainfall. Water at the base of the plant to avoid wetting the foliage, especially with our humid conditions, to minimize the risk of fungal diseases.

Watch for signs of underwatering, such as wilting or yellowing leaves. Overwatering, on the other hand, can lead to root rot and floppy growth. A layer of mulch around the base of the plants can help retain moisture and suppress weeds, but don't overdo it – Yarrow prefers well-drained soil.

Deadheading is key to keeping your Yarrow blooming throughout the season. Remove spent flowers as soon as they start to fade to encourage a second flush of blooms. This keeps the plant looking tidy and prevents it from putting energy into seed production.

In the fall, after our first frost around mid- October, cut the plant back to its basal foliage (the leaves at the base of the plant). Yarrow can be aggressive, so divide clumps every 2-3 years to prevent overcrowding.

You can expect your first harvest of Yarrow flowers from late June through late October. Harvest the flowers for drying when they are fully open and the color is vibrant. This is usually about 65 days after planting.

Cut the stems at the base of the flower head, taking care not to damage the surrounding foliage. Hang the flowers upside down in a cool, dark, and dry place to dry. Regular harvesting encourages continued production throughout the season.

As our first frost approaches in mid- October, harvest any remaining flowers before they are damaged by the cold. You can still dry them, even if they aren't quite as perfect.

Yarrow is generally easy to grow, but here are a few common problems we see in the Mid-Atlantic:

Spreads Aggressively

• What it looks like: Yarrow can quickly spread via rhizomes, forming dense colonies and potentially crowding out other plants.
• What causes it: Our even rainfall and moderate-to-hot summer temperatures provide ideal growing conditions, allowing it to spread rapidly.
• How to fix/prevent it: Plant in a contained area or use edging to prevent spreading. Divide the plants every 2-3 years to keep them in check.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes fruit. Leaves curl, yellow, and die. Reduces plant vigor.
• What causes it: Various fungi that thrive in warm days, cool nights, and moderate humidity. Dry leaf surfaces actually favor it. Our humid summers make Yarrow susceptible.
• How to fix/prevent it: Improve air circulation through spacing and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays help. Milk spray (1 part milk to 9 parts water) is surprisingly effective. Plant resistant varieties.

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 summers can lead to aphid infestations.
• 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).

Mid-Atlantic Specific Challenges: The moderate-to-hot heat, humid humidity, and even rainfall of the Mid-Atlantic can create favorable conditions for powdery mildew and aphid infestations. Regular monitoring and preventative measures are key to keeping your Yarrow healthy.

Yarrow makes a great companion plant in the Mid-Atlantic garden! It attracts beneficial insects like ladybugs and lacewings, which prey on aphids and other pests.

Good companions include tomatoes and peppers, as the beneficial insects attracted by Yarrow help protect them from pests. It also pairs well with herbs, enhancing their growth and fragrance. Strawberries also benefit, as Yarrow can help deter pests that attack them. Avoid planting near plants in the brassica family, like cabbage and broccoli, as Yarrow can attract cabbage moths.