Yarrow in Zone 7A — Texas

Yarrow is a workhorse in the Texas garden. It's easy to grow, the blooms are beautiful fresh or dried, and the plant attracts beneficial insects to your garden. Plus, it's incredibly drought-tolerant, which is a huge win when dealing with our unpredictable rainfall and the brutal Texas heat.

Texas weather can be challenging, with temperature swings and the occasional hailstorm. But yarrow is a hardy perennial, and with our long 245-day growing season, you'll have plenty of time to get it established and enjoy its benefits.

Starting yarrow indoors in Texas is an option, especially if you want a head start, but it's not strictly necessary. If you're aiming for blooms the first year, it's worth considering. Start seeds indoors from late December through mid January, about eight weeks before you plan to transplant.

Use seed trays with a good seed-starting mix. Keep the soil consistently moist (bottom watering helps prevent damping off) and provide plenty of light – a grow light works wonders. Because we often have an early spring, starting indoors gives you larger plants ready to go when the weather cooperates.

Transplant your yarrow seedlings outdoors from early to late March, after the danger of any hard freezes has passed. Harden off your seedlings for about a week before transplanting, gradually exposing them to outdoor conditions. This helps them adjust to the Texas sun and wind.

Space your plants 12-18 inches apart. Yarrow is a perennial, so choose a location where it has room to spread. Consider buying starts if you want flowers the first year.

Direct sowing yarrow is perfectly feasible in Texas. Sow seeds from mid March through late August. This gives you a wide window, taking advantage of our long growing season.

Prepare the soil by loosening it and removing any weeds. Yarrow prefers well-drained soil. Lightly press the seeds into the soil surface; they need light to germinate. Keep the soil consistently moist until seedlings emerge. Thin seedlings to 12-18 inches apart.

Yarrow is incredibly drought-tolerant once established, which is a huge plus in Texas. However, young plants need consistent moisture to get started. During the hottest parts of summer, even established plants might need a little supplemental watering.

In spring and fall, water deeply about once a week, especially if rainfall is scarce. The "finger test" is your friend: stick your finger about two inches into the soil. If it feels dry, it's time to water. Established plants usually only need about an inch of water per week. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our variable humidity.

During the extreme heat of summer, monitor your yarrow closely. If the leaves start to droop or look stressed, give it a good soak. Yellowing leaves can indicate overwatering, especially if the soil stays consistently wet. A layer of mulch around the base of the plant helps retain moisture and suppress weeds, but don't pile it against the stem.

Deadheading is key to keeping your yarrow blooming throughout the season. Snip off spent flowers as soon as they start to fade. This encourages the plant to produce more blooms.

In late fall, after the first frost around mid- November, cut the plant back to its basal foliage (the leaves at the base of the plant). Yarrow can be aggressive, so divide the plant every 2-3 years to keep it from taking over your garden.

You can expect your first yarrow harvest from mid May through late November, depending on when you planted. The flowers are ready to harvest when they are fully open and the colors are vibrant.

Cut the stems just above a leaf node. For drying, hang the stems upside down in a cool, dark, and dry place. Regular harvesting encourages more blooms, so keep cutting those flowers! Even as the first frost approaches in mid- November, you may still be able to harvest some late blooms.

Here are some common problems you might encounter with yarrow in Texas:

Spreading Aggressively

• What it looks like: Yarrow quickly expands beyond its intended area, crowding out other plants.
• What causes it: Yarrow spreads by rhizomes (underground stems) and seeds. Our long growing season can contribute to its rapid spread.
• How to fix/prevent it: Plant yarrow in a contained area, such as a raised bed or surrounded by edging. Regularly divide the plant every 2-3 years to control its spread. Remove seed heads before they mature to prevent self-seeding.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes fruit. 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. Avoid excess nitrogen fertilizer.

Texas Specific Challenges: The hot-to-extreme heat and variable humidity of Texas can stress yarrow, making it more susceptible to powdery mildew and aphid infestations. Consistent monitoring and prompt action are key to keeping your plants healthy. The unpredictable rainfall also means you need to be vigilant about watering, adjusting your schedule based on the weather.

Yarrow is a great companion plant in the Texas garden. It attracts beneficial insects like ladybugs and lacewings, which prey on pests that can damage your tomatoes and peppers. Plant yarrow near your tomatoes and peppers to help protect them from aphids and other pests.

Yarrow also makes a good companion for herbs like rosemary and thyme, as it helps to improve the soil and attract pollinators. Strawberries also benefit from having yarrow nearby, as it can help to deter pests and diseases. Avoid planting yarrow near plants in the Brassica family (cabbage, broccoli, kale), as it can attract cabbage moths.