Yarrow in Zone 5B — Great Plains

Yarrow is a fantastic plant for Plains gardeners. Its feathery foliage and clusters of blooms add beauty to any garden, and it's incredibly versatile. You can use it in fresh or dried arrangements. Plus, it attracts beneficial insects like crazy, making it a great addition to vegetable gardens. The best part? It thrives in our intense sunshine and well-draining prairie soil.

Our Great Plains climate can be unpredictable, with extreme temperature swings, occasional hail, and periods of drought. But don't worry, Yarrow is a tough cookie. With a 178-day growing season, you have plenty of time to get this plant established and enjoy its benefits. Careful timing and a little attention to watering are key.

Starting Yarrow indoors in our region is possible, but it's not always necessary since it direct sows so easily. If you're looking for a head start, especially to get flowers in the first year, starting indoors makes sense.

Begin in early to late February, about 8 weeks before you plan to transplant. Use seed trays with a good seed-starting mix. Provide warmth and plenty of light – a grow light is beneficial. Water from the bottom to avoid damping off, which can be an issue in our variable spring weather.

Transplanting Yarrow is best done in early April through early May. This allows the plant to establish itself before the heat of summer arrives. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week.

Space them 12-18 inches apart in a sunny spot. Keep an eye on the weather forecast – a late frost can happen. If you're buying starts, you'll likely get blooms the first year, which is a nice bonus.

Direct sowing Yarrow is a simple and effective method in the Great Plains. You have a wide window, from mid-April through late July, to sow seeds directly into your garden.

Prepare the soil by loosening it and removing any weeds. Yarrow prefers well-drained soil, which most of our prairie soil is. Sow the seeds shallowly and keep the soil consistently moist until they germinate. Thin seedlings to 12-18 inches apart.

Yarrow is remarkably drought-tolerant once established, making it perfect for our variable rainfall patterns in the Great Plains. However, getting it established requires careful watering in the first year.

During the spring, water thoroughly whenever the top 2 inches of soil feel dry to the touch – use the finger test. Typically, an inch of water per week is sufficient. In the heat of summer (typical high: 93°F), you might need to water more frequently, but still avoid overwatering. Water at the base of the plant to prevent fungal diseases, especially since we can have periods of moderate humidity.

Yellowing leaves are a sign of overwatering, while wilting leaves indicate underwatering. A light layer of mulch, like shredded bark, can help retain moisture and suppress weeds, but don't overdo it, as Yarrow prefers well-drained soil.

Pruning Yarrow is straightforward and helps encourage continued blooming. The most important thing is to deadhead spent flowers throughout the growing season. Snip off the flower heads as soon as they start to fade. This encourages the plant to produce more blooms.

In the fall, after the first frost around mid- October, cut the plant back to its basal foliage. This prepares it for winter dormancy. Yarrow can be aggressive, so divide the plants every 2-3 years to prevent them from taking over your garden.

You can expect your first Yarrow harvest from late June through late October, about 65 days after planting. Harvest the flowers for drying when they are fully open and their color is vibrant. These make excellent dried flowers.

To harvest, simply cut the stems with sharp scissors or pruners. Leave enough stem on the plant to encourage continued growth. Regular harvesting encourages more blooms. As the first frost approaches in mid- October, harvest any remaining flowers to dry before they are damaged by the cold.

Here are the top 3 problems you might encounter growing Yarrow in the Great Plains:

Spreading Aggressively

• What it looks like: Yarrow quickly expands beyond its designated area, crowding out other plants.
• What causes it: Yarrow spreads via rhizomes (underground stems). Our prairie soil, while fertile, can sometimes encourage aggressive growth.
• How to fix/prevent it: Plant Yarrow in a contained area or use edging to prevent it from spreading. Regularly divide the plant every 2-3 years to keep it in check.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes flowers. Leaves curl, yellow, and die.
• What causes it: Various fungi that thrive in warm days, cool nights, and moderate humidity. Dry leaf surfaces actually favor it.
• 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.

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.
• 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.

Great Plains Specific Challenges: Our hot summers and variable rainfall can exacerbate powdery mildew if air circulation is poor. The wind can also contribute to the spread of aphids. Drought stress can make plants more susceptible to both problems. Ensure your Yarrow has adequate spacing, monitor for pests regularly, and water deeply but infrequently to promote healthy, resilient plants.

Yarrow is a great companion plant in the Great Plains garden. It attracts beneficial insects that help pollinate and protect other plants.

Good companions include tomatoes and peppers because Yarrow attracts predatory insects like ladybugs and lacewings, which feed on aphids that commonly attack these vegetables. Herbs like rosemary and thyme also benefit from Yarrow's insect-attracting properties. Strawberries benefit from the increased pollination Yarrow provides.

Avoid planting Yarrow near plants that prefer very rich, moist soil, as Yarrow thrives in drier conditions.