1. Choose the appropriate yarrow variety: Before planting yarrow, decide which type you prefer. Common yarrow (Achillea millefolium) and fernleaf yarrow (Achillea filipendulina) are popular choices.

2. Prepare your soil: Yarrow prefers well-draining soil with a pH between 5.5 and 7.0. To improve drainage, consider adding organic matter like compost or aged manure.

3. Select an optimal location: Plant yarrow in an area with full sun, ensuring that it receives at least six hours of direct sunlight each day.

4. Plant yarrow seeds or divisions: You can grow yarrow from seeds, root divisions, or small plant starts. Space seeds, divisions, or plant starts 1-2 feet apart to allow ample room for growth.

5. Water inconsistently but deeply: Do not overwater your yarrow plants; they are drought-tolerant and can handle infrequent watering. Water them deeply once every couple of weeks to encourage strong root growth.

6. Add support structures if necessary: If your yarrow tends to flop over, you might need to support the plants with stakes or cages.

7. Fertilize sparingly: Yarrow has low nutrient requirements and rarely needs fertilizing. If needed, apply a phosphorus-rich fertilizer once during the growing season to promote flowering.

8. Deadhead spent blooms: Remove faded flowers to enhance the plant’s appearance and encourage additional blooming.

9. Divide the plants every few years: Multiply your yarrow by dividing the plants in spring or fall; this also helps maintain their health by controlling their size.

10. Control pests and diseases: Yarrow is relatively disease-free and pest-resistant; however, keep an eye out for aphids and powdery mildew, which can occasionally affect the plants.

11. Water properly during overcast days: Yarrow might experience mildew issues if it remains moist for too long. On cool or overcast days, water early in the day to give your plants time to dry before nightfall.

12. Apply mulch for weed control: Use a layer of organic mulch around your yarrow plants to suppress weeds, retain soil moisture, and regulate soil temperature.

13. Prune your plants for size and shape: After the first frost, trim your yarrow back to about 3 inches above the ground to promote fresh growth in the coming season.

14. Prepare for winter: In colder climates, cover your yarrow plants with a layer of straw or other insulating material to protect them from harsh winter temperatures.

15. Harvest and use yarrow: Yarrow can be used for culinary purposes, such as making teas or adding its leaves to soups and salads; or it can be used medicinally or as an ornamental in flower arrangements. Harvest yarrow flowers when they are at their peak, and store them in a cool, dark place until ready to use.