Yarrow in Zone 6A — Mid-Atlantic

Yarrow is a fantastic addition to any Mid-Atlantic garden. Not only does it produce beautiful, long-lasting flowers perfect for cutting and drying, but it also attracts beneficial insects to your garden. Plus, it's incredibly low-maintenance once established, making it a great choice for our often-busy lives here with four distinct seasons.

Our humid summers and variable spring weather can present challenges, but Yarrow is surprisingly resilient. With a growing season that stretches nearly 190 days, you'll have plenty of time to enjoy its blooms. Proper timing and a little attention to soil drainage are all you need to succeed.

Starting Yarrow indoors isn't strictly necessary, but it can give you a head start, especially if you want those blooms the first year. If you choose this route, sow seeds indoors from late January through mid February, about eight weeks before you plan to transplant.

Use seed trays with a good seed-starting mix, and be sure to provide warmth and light. Bottom watering is a great way to keep the soil consistently moist without overwatering, which young Yarrow seedlings dislike. Spring weather in the Mid-Atlantic can be unpredictable, so starting indoors buys you some time and ensures your plants are strong enough to handle any late frosts.

Transplant your Yarrow seedlings outdoors from early to late April, after the danger of hard frost has passed. Be sure to harden them off first by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

Space your plants 12-18 inches apart to allow for good air circulation, which is important in our humid climate. Keep an eye on the weather forecast – those late-season temperature swings can still happen. Since Yarrow is a perennial, buying starts might be the best way to ensure you get flowers the first year.

Direct sowing Yarrow is a perfectly viable option, and it's definitely the easiest. Sow seeds from mid April through early August, once the soil has warmed up a bit.

Prepare the soil by loosening it and removing any large clumps. Yarrow isn't picky, but well-drained soil is key. Scatter the seeds on the surface and gently press them into the soil. Space them about 12-18 inches apart, or thin seedlings to that spacing later. Keep the soil consistently moist until the seedlings emerge, which can take a couple of weeks.

Yarrow is remarkably drought-tolerant once it's established, making it a great choice for our region. While we get reliable rainfall, our summers can still bring periods of moderate-to-hot heat and humidity, so understanding its watering needs is still important.

In the spring, when the plants are young, water them regularly to help them get established. Once they're mature, you can ease up. A good rule of thumb is to stick your finger about two inches into the soil. If it feels dry, it's time to water. Aim for about an inch of water per week, either from rainfall or irrigation.

Water at the base of the plant rather than overhead, especially in our humid summers. This helps prevent fungal diseases. Signs of underwatering include wilting leaves and dry, brittle stems. Overwatering, on the other hand, can lead to floppy growth and root rot. 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. Simply snip off the spent flower heads as soon as they start to fade. This encourages the plant to produce more flowers.

You can deadhead anytime from mid June through late October as the flowers fade. In the fall, after the first frost around mid- October, cut the plant back to its basal foliage. Yarrow can be a bit aggressive, so consider dividing it every 2-3 years to keep it in check.

You can expect your first Yarrow harvest about 65 days after planting, typically from mid June through late October in our region. The best time to harvest the flowers for drying is when they are fully open and the colors are vibrant.

To harvest, simply cut the stems just above a leaf node. This encourages the plant to produce more blooms. Yarrow doesn't ripen off the vine, but it does dry beautifully. To encourage continued production, keep deadheading spent flowers. As the first frost approaches in mid- October, harvest any remaining flowers for drying.

Yarrow is generally a tough plant, but here are a few common problems you might encounter in the Mid-Atlantic:

Aggressive Spreading

• What it looks like: Yarrow can spread quickly via rhizomes, popping up in unwanted areas of your garden.
• What causes it: Its vigorous growth habit, combined with our region's reliable rainfall, can lead to it spreading beyond its intended space.
• How to fix/prevent it: Plant Yarrow in a contained area or be prepared to regularly dig up and remove unwanted shoots. Divide the plant every few years to control its size.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves and stems. Leaves may curl, yellow, and eventually die.
• What causes it: This fungal disease thrives in our warm days, cool nights, and moderate humidity. It's surprisingly favored by dry leaf surfaces.
• How to fix/prevent it: Improve air circulation by spacing plants adequately and pruning. Remove affected leaves promptly. Neem oil or potassium bicarbonate sprays can help. A milk spray (1 part milk to 9 parts water) is also effective.

Aphids

• What it looks like: Clusters of tiny green, black, or white insects on stems and undersides of leaves. Sticky honeydew residue and curled or distorted new growth.
• What causes it: These sap-sucking insects reproduce rapidly, especially in our warm weather. Ants may even "farm" them for their honeydew.
• How to fix/prevent it: Knock them off with a strong spray of water. Encourage natural predators like ladybugs and lacewings. Use insecticidal soap for heavy infestations or neem oil systemically. Avoid excessive nitrogen fertilizer, which attracts them.

Mid-Atlantic Specific Challenges: Our moderate-to-hot heat, humid humidity, and even rainfall create conditions that can favor powdery mildew and aphid infestations. Good air circulation and vigilant monitoring are key to keeping your Yarrow healthy.

Yarrow makes a great companion plant for several reasons. It attracts beneficial insects like ladybugs and lacewings, which prey on pests like aphids and whiteflies, helping to protect your tomatoes and peppers. It's also said to improve the health and vigor of herbs like rosemary and thyme. Yarrow can also be planted near strawberries to deter pests.

There aren't any truly bad companions for Yarrow, but you might want to avoid planting it near other aggressive spreaders, as they could compete for resources. Otherwise, Yarrow is a pretty easygoing companion in the Mid-Atlantic garden.