YARROW

Cultivation

Yarrow (Achillea millefolium L.) is a low-growing perennial stoloniferous herb. Yarrow produces small white (sometimes pink) flowers in clusters atop a three foot stem. Wild white variety and pink are the most medicinal.  Red and yellow flowered varieties have been bred for flower gardens and should not be used internally. Yarrow is native to Europe and Asia is commonly found in the temperate regions of the world as a native or a cultivated plant or weed.

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Yarrow can grow to 3’ tall in good soil. You’ll often find it growing along the side of the road or a path, in fields and meadows, and in places where the soil has been disturbed in the past. It likes to grow in full sun but can also do quite well in part shade.  Yarrow propagates itself through seed, spreading rhizomes and underground stems, so it can spread quickly and is easily multiplied.

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Traditionally just the flowers were harvested, you harvest the roots and use all the aerial parts (leaves and flowers) because the upper stem and leaves retain their strength longer. To harvest the aerial parts, simply cut the stem just below the lowest green leaves. 

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1. Sow seeds in fall or early spring. Yarrow seeds need a cold, wet period to germinate, so you should sow the seeds in fall or early spring to give them time to begin blooming during spring and summer. The germination period usually lasts about two weeks

2. Conduct the germination process indoors. If you choose to plant the seeds in late spring, you’ll want to complete a process called stratification that duplicates the cold, wet period needed to prepare temperate zone seeds for growing. Wrap the seeds in a wet paper towel and seal them in a plastic bag or put them in wet sand and refrigerate them for 4 weeks prior to planting

3. Position the seeds no deeper than 0.25 inches (0.64 cm) below the surface.Some light is needed for the germination process, so you don’t want to plant the seeds too deep

4. Space the seeds 1–2 feet (0.30–0.61 m) apart. Yarrow produces large, robust roots, so you need to make sure you give the plant room to grow

5. Transplant a mature yarrow if you're not using seeds. Like most perennials, yarrows can easily be transplanted from a pot to its new home. Dig a hole twice the size of the pot and make sure to water the plant and the new location thoroughly before transfer

   • Filling the hole with water until it takes longer than 20 minutes for the water to soak into the ground is a great way to make sure there is enough moisture

   • For the best results, transplant yarrow in the fall or spring

   • The root ball should be even with the surface

6. Choose a sunny location to plant. Yarrow can tolerate some shade, but a full-sun area is ideal for the best growth. Too much shade can lead to flimsy stems, foliar disease, or rot.  Be aware that a humid climate can contribute to powdery mildew disease, which is mostly cosmetic but still something to consider

7. Avoid soil with excessive moisture. Yarrow grows best in drier soil but will still flourish in moist soil if it is properly drained.[10] If you notice that the soil retains a lot of water or always looks wet, it’s probably not a good location to plant yarrow.  Soils composed of sand tend to drain sufficiently, whereas clay-based soils do not. Creating a berm or raised bed with a mixture of clay and coarse sand can allow for better drainage if necessary

8. Give yarrow space. The roots become extremely dense once the plant matures. This can be beneficial for keeping weeds at bay but harmful for other plants

9. Water your yarrow deeply at least once a week the first summer. Although yarrow likes dry soil, watering helps the plant develop its thick roots and sets the stage for longevity and growth. If rainfall is more than an inch per week, you can let nature take care of this step.

10. Cut back the plant after the first frost. To stimulate new growth and enhance the appearance of yarrow, it is recommended that you cut the stems down to 1-2 inches above the surface after its first winter. Cut the stems at an angle to avoid water buildup in the stem.

11. Dig up the plants and divide them every 3-4 years. Because yarrow can easily reseed and grows quickly, it can start to become unruly every few years. By thinning it out, you control which areas it spreads to and when. Using a gardening fork, start at the crown of the plant and gently work your way outward to lift the plant out of the ground. Then, divide into a few stalks per bunch by pulling or cutting if necessary and transplant the smaller bundles to their new home.

12. Allow for good airflow. Yarrow is prone to fungal disease, especially in humid climates. By making sure the leaves and blooms have good airflow, you can help prevent it

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Yarrow dries very quickly, so you’ll probably be able to move it from your drying racks to a storage container within a few days. Spread in a single, even layer to dry in a space with good airflow.

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It makes a lovely lawn replacement (or addition) and can be planted instead of monocrop grasses. It’s easy to mow and can be kept quite short.  It does not burn easily so it can be used as a fire barrier and it can help stop erosion.