Yarrow in Zone 9B — Texas

Yarrow is a fantastic addition to any Texas garden. It's not just pretty with its clusters of flowers; it's also incredibly useful. It attracts beneficial insects to your garden, which is a huge help when dealing with pests. Plus, you can dry the flowers for arrangements, adding a touch of your garden to your home.

Our unpredictable weather here in Texas can be challenging, but Yarrow is pretty forgiving. With our long growing season (around 308 days), you have plenty of time to get it established and thriving. Just keep an eye on the watering, especially during the brutal Texas heat.

Starting Yarrow indoors gives you a jump start, especially if you want blooms the first year. It’s not strictly necessary, since you can direct sow, but if you're eager, go for it.

Start your seeds indoors from mid-November through mid-December. This gives them about 8 weeks before you'll want to transplant them outside. Use seed trays with a good seed-starting mix, keep them warm, and provide plenty of light, either with a grow light or a sunny window. Don’t forget to water from the bottom to keep the soil evenly moist without soaking the seedlings. With our early spring here in Texas, getting a head start can really pay off.

Transplanting Yarrow is best done from late January through mid-February. Before you move your seedlings outside, harden them off. This means gradually exposing them to outdoor conditions for about a week.

Space your Yarrow plants 12-18 inches apart to give them room to spread. Keep in mind that Texas weather can be unpredictable even in late winter. Watch out for any unexpected freezes and be ready to cover your young plants if necessary. Yarrow is a perennial, so buying starts will give you flowers the first year, but either way you'll have years of beauty.

Direct sowing Yarrow is a straightforward option, and it works well in our Texas climate. You can direct sow from early February through late September.

Prepare your soil by loosening it and removing any weeds. Yarrow isn't picky, but it does need well-drained soil. Sprinkle the seeds on the surface and gently press them in. They need light to germinate, so don't bury them too deep. Keep the soil consistently moist until the seedlings emerge. Remember to thin them to 12-18 inches apart once they're a few inches tall.

Watering is crucial, but it’s easy to overdo it with Yarrow, especially in Texas. Yarrow is drought-tolerant once established, and it actually prefers drier conditions. Overwatering leads to floppy growth and other problems.

During the spring and fall, when temperatures are milder, water your Yarrow only when the top 2 inches of soil feel dry to the touch – use the finger test! In the brutal Texas heat of summer, you might need to water once a week, giving it about an inch of water. Pay attention to the plant. If the leaves start to wilt or droop, it's a sign it needs a drink.

Water at the base of the plant rather than overhead, especially with our variable humidity. Wet foliage can encourage fungal diseases. Signs of underwatering include wilting leaves and stunted growth. Overwatering shows as yellowing leaves and limp stems. Add a layer of mulch around your plants to help retain moisture and suppress weeds; just keep it away from the base of the stems.

Pruning Yarrow is simple and helps keep it looking its best. The main thing is to deadhead spent flowers.

Deadheading means removing the faded blooms. This encourages the plant to produce more flowers throughout the season. Just snip off the flower heads right below the bloom. Do this regularly, especially after the first flush of blooms in spring. As our first frost approaches in early December, cut the plant back to its basal foliage. This helps it overwinter and come back strong in the spring. Keep in mind that Yarrow can be aggressive, so divide it every 2-3 years to keep it in check.

Harvesting Yarrow is rewarding, and you can enjoy the fruits (or rather, flowers) of your labor for a long time. You can expect your first harvest from mid-April through mid-December.

Harvest the flowers when they are fully open and the color is vibrant. This is when they're at their peak for drying. Cut the stems long, leaving enough foliage on the plant to keep it healthy. To dry the flowers, bundle them together and hang them upside down in a cool, dark, and dry place. Yarrow is a continuous harvest plant, so the more you harvest, the more it will produce. As the first frost gets closer in early December, harvest any remaining flowers before they get damaged by the cold.

Even though Yarrow is relatively easy to grow, you might encounter a few problems in Texas. Here are three common ones:

Spreading Aggressively

• What it looks like: Yarrow starts popping up in areas where you didn't plant it, quickly taking over garden beds.
• What causes it: Yarrow spreads through rhizomes (underground stems). In our long growing season, it has plenty of time to spread.
• How to fix/prevent it: Plant Yarrow in containers or use edging to contain its spread. Regularly divide the plant every few years to keep it in check. Remove unwanted shoots as soon as you see them.

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 (unlike most fungi).
• 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.
• 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). And watch out for those fire ants protecting their honeydew source!

Texas Specific Challenges: Our hot-to-extreme heat, variable humidity, and unpredictable rainfall can exacerbate these problems. The heat can stress the plants, making them more susceptible to pests and diseases. Variable humidity can create ideal conditions for powdery mildew. And unpredictable rainfall can lead to overwatering or underwatering if you're not careful. Keep a close eye on your Yarrow, adjust your watering as needed, and take action quickly if you spot any problems.

Yarrow makes a great companion plant in the Texas garden. It attracts beneficial insects like ladybugs and hoverflies, which prey on pests.

Good companions include tomatoes and peppers because Yarrow helps to protect them from pests. It also works well with herbs like rosemary and thyme. It is also a good companion for strawberries. Avoid planting Yarrow near plants that prefer consistently moist soil, as Yarrow thrives in drier conditions.