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Yarrow
Yarrow (Achillea) is a hardy herbaceous perennial flower celebrated for its flat-topped clusters of tiny blooms and finely dissected, fern-like foliage. Among the many types of flowers grown in ornamental gardens, yarrow stands out for its unique combination of beauty and resilience. This plant forms clumps of feathery green leaves that emit a faint herbal aroma when brushed, and in summer it sends up upright stems topped with broad flower heads that can span 2 to 6 inches across. The blooms are actually dense composites of dozens of mini florets, giving a “plate” of color that attracts butterflies and other pollinators. As one of the classic perennial garden plants used in cottage borders, meadows, and xeriscapes, yarrow is both decorative and very adaptable. It thrives in tough conditions where fussier flowers may fail. Gardeners appreciate Achillea as one of the most easy-care flowering herbs, requiring minimal attention once established. Yarrow tolerates drought, heat, and poor soils better than most ornamentals, and it is rarely troubled by deer or rabbits thanks to its bitter taste. With a history of use in traditional medicine and a firm place in modern landscaping, Achillea serves as a bridge between wildflower charm and reliable garden performance.
🌱 Taxonomy and origin
The genus Achillea comprises about 80 to 100 species of perennial herbs in the daisy or sunflower family (Asteraceae). These species are native across temperate regions of the Northern Hemisphere, especially Europe and Asia, with some also found in North America. Achillea millefolium, known as common yarrow, is originally from Eurasia but has become naturalized in North America and other parts of the world. Related species include Achillea filipendulina (fernleaf yarrow) from western Asia, which produces tall stems and golden-yellow flower clusters, and Achillea ptarmica (sneezewort) native to Europe, bearing white button-like blooms. The genus name Achillea originates from the Greek hero Achilles, who according to legend used yarrow to treat soldiers’ wounds during the Trojan War. The species name “millefolium” means “thousand leaf,” referring to yarrow’s finely divided foliage. In its native habitats, wild yarrow typically grows in open meadows, grasslands, and along roadsides, thriving in dry, disturbed soils. This plant has a very long association with humans: yarrow remains have even been found in ancient burial sites, hinting at its medicinal use. Modern ornamental yarrows are often hybrid selections derived from common yarrow and other species, bred for sturdier stems and a wider palette of flower colors.
🌸 Bloom time
Yarrow’s blooming period extends from late spring into early fall. Yarrow generally begins flowering in May or June and continues through the summer months, often into September, especially if regularly deadheaded. Each flat-topped inflorescence remains attractive for weeks, and trimming off the spent clusters can encourage additional flushes of bloom. Peak bloom is typically in mid-summer when the plants are in full display. The tiny individual florets open in succession across the cluster, giving a prolonged show. Common yarrow (Achillea millefolium) usually bears white or pale blush blooms in the wild, but cultivated varieties offer a rainbow of colors. Garden yarrows can produce vibrant yellow flowers, rich reds, oranges, soft pink flowers, lavender-purple tones, and creamy pastels. For instance, the popular hybrid ‘Moonshine’ yields bright sulfur-yellow umbels, while ‘Paprika’ is known for its spicy red blooms that age to softer shades. With good care, many Achillea cultivars will rebloom after the first flush, providing color well into late summer. One hue you won’t find in yarrow’s spectrum is true blue. However, gardeners often pair yarrow with blue flowers such as salvia or catmint. The golden and pink yarrow blossoms stand out vividly against cool blue-toned companions, creating a striking contrast in mixed plantings.
📏 Height and spread
Most garden yarrow varieties reach about 2 to 3 feet tall (60 to 90 cm) when in full bloom, with a similar spread. The growth habit is upright but loose, consisting of a clump of basal foliage with slender flowering stems rising above. There are also more compact selections around 1 to 2 feet high, and conversely some taller types. For example, certain fernleaf yarrow cultivars can approach 4 feet in height under ideal conditions. Yarrow plants tend to spread gradually via creeping rhizomes, forming a wider clump or colony over time. In favorable conditions, a single plant may colonize an area 2 to 3 feet across within a few seasons through underground stems and self-seeding. Gardeners typically space new yarrow transplants about 1 to 2 feet apart to allow for this eventual spread. The feathery foliage stays near ground level in a mound roughly 6 to 12 inches tall, while the flower stalks tower above the leaves. The overall effect is an airy silhouette with flat flower clusters hovering at the top of the stems. Despite reaching a few feet high, yarrows have a sturdy yet light form that generally sways in the breeze rather than requiring stakes.
☀️ Light
Full sun is the ideal light condition for yarrow. These plants truly flourish with at least 6 hours of direct sunlight per day, and they perform best in open, unshaded locations. In ample sun, yarrow produces more flowers and sturdier stems, maintaining a compact habit. It can tolerate partial shade (for example, a few hours of dappled light or afternoon shade), but in too much shade yarrow tends to stretch and become leggy with diminished bloom. Plants grown in insufficient sun are also more prone to flopping over and to diseases like powdery mildew due to the higher humidity and lower airflow in shady spots. In cooler northern climates or at higher elevations, yarrow relishes full sun all day long. In very hot or dry regions, a short respite from intense afternoon sun can help prevent leaf scorch, but overall this species thrives under bright light. Providing plenty of sun will ensure robust growth, abundant flowering, and a neat, upright form for Achillea.
💧 Water
Yarrow has modest water needs and is quite drought-tolerant once established. It prefers dry to moderately moist soil and will suffer if kept too wet for long. Good drainage is essential, as waterlogged conditions can lead to root rot or stem rot in Achillea. In fact, yarrow often thrives in the same low-water environments favored by other hardy herbs like lavender and sage. During the first growing season after planting, some regular watering is needed to help the roots establish, but even then the soil should not remain constantly soggy. Once mature, yarrow typically gets by on natural rainfall in most climates, and may only require supplemental watering during extended hot, dry spells. When irrigating, it is best to water deeply but infrequently, allowing the topsoil to dry out between sessions. Overly frequent watering (or very fertile soil) tends to make the plants grow lush and floppy, so keeping yarrow a bit on the dry side produces sturdier growth. In summary, an occasional soak during prolonged drought is usually all this resilient perennial requires, whereas daily watering or heavy irrigation is unnecessary and can be harmful.
🌍 Soil and pH
Yarrow grows best in lean, well-drained soil. In its natural habitats it often occurs on sandy or rocky ground with low fertility, and it adapts readily to average garden soil as long as excess water can drain away. Rich, heavily amended soil is not necessary. In fact, too much organic matter or fertilizer can lead to overly tall, weak growth that flops over easily. A gritty or sandy loam is ideal for Achillea. Heavy clay soils that retain water are problematic. If planting in clay, it is important to improve drainage by mixing in coarse sand or fine gravel, and to avoid overwatering. Yarrow tolerates poor soils that many fussier ornamentals struggle in, and it can even help improve soil quality over time by mining minerals from deeper layers with its roots. As for pH, yarrow is not very picky. It grows across a broad pH range from slightly acidic to mildly alkaline (approximately pH 6.0 to 8.0). This means gardeners usually do not need to adjust soil chemistry specifically for yarrow. Overall, a moderately fertile, dry, well-draining substrate will keep this plant healthy. There is little need for additional fertilizer. Yarrow truly thrives with relatively spartan soil conditions.
❄️ USDA hardiness
Common yarrow and most Achillea cultivars are hardy across a wide range of climates. Generally, yarrow grows well in USDA hardiness zones 3 through 9, which corresponds to regions with winter low temperatures around -30 °F (-34 °C) in zone 3. Some strains can survive even colder zone 2 conditions if given protective snow cover or mulch. At the warm end, Achillea handles climates with mild winters and hot summers up to zone 9. In these warmer areas, it often overwinters as evergreen or semi-evergreen basal foliage if frosts are light. In cold-winter zones, yarrow goes completely dormant, dying back to the ground and re-sprouting from its roots in spring. Yarrow’s impressive cold tolerance makes it suitable for high elevations and northern latitudes, provided the soil drains well (excess winter wetness is more harmful than cold itself). It also withstands summer heat reasonably well, especially in dry climates. However, humid subtropical conditions (zone 10 and above) can be challenging for this plant, since it prefers a distinct winter dormancy and drier air. Overall, gardeners across most of the United States can grow yarrow successfully. From the northern plains to milder southern regions, this hardy perennial reliably returns each year within its zone range.
🌼 Propagation and longevity
Yarrow can be propagated from seed with relative ease. The seeds are very small and need light to germinate, so they are best sown on the surface of a prepared seed bed or potting mix without burying them deeply. Seeds may be started indoors 8 to 10 weeks before the last frost or sown outdoors in early spring (they can also be scattered in fall for natural cold stratification over winter). With adequate moisture and warmth, seedlings typically emerge within 1 to 3 weeks. Plants grown from seed may even bloom in their first summer if started early, though many will wait until the second year to flower. Note that seeds collected from hybrid cultivars might not produce offspring identical to the parent’s color or size.
Established yarrow clumps are easily divided to produce new plants and to reinvigorate the originals. It is usually recommended to divide the clumps every 2 to 3 years. To divide, dig up a mature clump in early spring or fall and split the root mass into sections, ensuring each piece has healthy roots and some shoots. Replant the divisions at the same depth in well-prepared soil. This process helps maintain vigorous growth, especially if the center of a clump has started to die out or the plant has become overcrowded. Yarrow also spreads on its own by creeping underground rhizomes. You may find small offshoot plants around the edges of an established patch. These can be dug up and transplanted elsewhere. In addition, stem cuttings of yarrow will root readily. A 3- to 4-inch long tip of a non-flowering shoot, taken in spring or early summer and placed in a moist, sandy medium, typically develops roots within a few weeks. This provides another way to clone a desirable variety.
Yarrow is generally a long-lived perennial. Each winter the top growth dies back in cold climates, but the plant re-sprouts from its hardy roots when spring arrives. Over the years a yarrow planting can persist for a very long time, especially if it is periodically divided to refresh it. Individual clumps may begin to decline after 4 to 5 years if left undivided, but by that time they often have produced younger offshoots around them. Thanks to this resilience and gradual self-propagation, once you establish yarrow in a garden it often remains for many years, forming an enduring presence and sometimes expanding into a broader colony.
👃 Fragrance
Yarrow is not particularly known for its fragrance, but it does have a subtle scent if one gets close. The plant’s foliage is aromatic, containing essential oils that give off a spicy, herbal smell when crushed or brushed. Some describe the scent of the leaves as similar to chamomile or pine with a hint of pepper or camphor. This distinctive aroma is noticeable if you handle or bruise the leaves, though it generally does not carry far in the garden. The flowers themselves have a faint sweetness. Some gardeners describe a light honey-like or mildly medicinal scent that can sometimes be detected on warm days, but it is not very strong. In comparison to more famously fragrant blooms like roses or gardenias, yarrow’s blossoms are quite modest in scent. Thanks to its aromatic oils, dried yarrow has been used in potpourri and herbal sachets, where its gentle earthy fragrance can be appreciated up close. Overall, Achillea’s fragrance is understated: pleasant in a mild, herbal way rather than as a powerful floral perfume.
⚠️ Toxicity and pet safety
Yarrow is not severely toxic to humans, but some caution is warranted with pets. Achillea contains certain compounds that can cause mild toxicity if large quantities are consumed. The American Society for the Prevention of Cruelty to Animals (ASPCA) lists yarrow as toxic to dogs, cats, and horses. In pets, ingesting yarrow may lead to drooling, vomiting, diarrhea, or depression. Fortunately, the bitter taste of the plant usually deters animals from eating very much of it. Serious poisonings are rare, but it is wise to prevent curious pets from chewing on yarrow. If a dog or cat does nibble the leaves or flowers, monitor them for any signs of illness and consult a veterinarian if symptoms occur.
For humans, yarrow is generally considered safe in small amounts, as it has even been used as a medicinal herb in teas and poultices. However, it should not be consumed to excess. Direct contact with yarrow can cause skin irritation or rashes in some people, especially those sensitive to plants in the aster family. Wearing gloves when handling a lot of yarrow foliage is a good precaution for gardeners with sensitive skin. In the garden, yarrow’s mild toxicity actually has an upside: deer and rabbits tend to avoid eating it. This means the plant provides deer resistant blooms that can be grown in areas frequented by wildlife, reducing damage from browsing animals.
🌿 Vase life
Yarrow makes an excellent cut flower thanks to its sturdy, long-lasting blooms. When harvested at the right stage, the flowers can remain fresh in a vase for about a week or more. The best time to cut yarrow for arrangements is when most of the tiny florets in each cluster have opened and the stems are firm. It is advisable to cut in the cool of early morning or evening, using clean, sharp shears. Remove any foliage that would sit below the water line in the vase to prevent decay. With proper conditioning, yarrow stems typically last around 7 to 10 days in fresh bouquets. They add interesting texture and pops of color, and pair well with other summer flowers in mixed arrangements.
Yarrow is also valued for dried flower crafts. The flat-topped blossoms hold their shape and some color when dried. To dry yarrow, hang the stems upside down in small bunches in a warm, dark, well-ventilated space for a couple of weeks. Once completely dried, the flowers will last for many months without water, making them ideal for everlasting arrangements, wreaths, and dried bouquets. Dried yarrow retains its form and a muted version of its original hue (golden yellows and pink-red tones tend to dry particularly well). Whether used fresh or dried, yarrow’s extended vase life and unique appearance make it a favorite for floral designers as well as home gardeners.
🐛 Pests and diseases
Yarrow is generally a trouble-free plant with relatively few pest or disease problems. Its aromatic foliage may even have some natural pest-repellent properties. In the garden, insect pests rarely cause significant damage to yarrow. On occasion, aphids might cluster on the stems or buds, especially on very lush new growth. These small sap-sucking insects can be washed off with a strong spray of water, or they will often be controlled by natural predators (yarrow tends to attract beneficial insects like ladybugs and lacewings that feed on aphids). Similarly, spittlebugs or mealybugs might sometimes appear on the stems, but serious infestations are uncommon. Overall, yarrow does not typically require any pesticides. In fact, it is known as a companion plant that can help reduce pest problems nearby by drawing in predatory insects.
Diseases are also infrequent in yarrow when it is grown in appropriate conditions. The most important factor is providing good drainage and avoiding overly damp, crowded situations. In poorly drained or waterlogged sites, yarrow’s roots and stems can be prone to rot (such as stem rot or root rot). Likewise, very humid or stagnant air conditions can lead to foliar diseases like powdery mildew or rust on the leaves. These fungal issues may appear as white powdery coating or rusty-orange spots, but they are not common in well-sited plantings. Proper spacing to ensure air circulation, and watering at the base of the plant rather than overhead, helps prevent mildew. If mildew or other leaf disease does occur, it can often be managed by cutting back the affected stems to allow fresh healthy growth. Another occasional issue is the tendency for tall yarrow stems to flop over, especially after heavy rain or if the soil is too rich. This can be addressed by cutting plants back by one-third in late spring (to promote a shorter, sturdier growth), or by staking the clumps in exposed locations. In summary, Achillea is a low-maintenance perennial with minimal pest and disease issues. Yet another reason it is favored by gardeners seeking easy-care flowers.
FAQs
Is yarrow invasive in the garden?
Yarrow spreads readily by seeds and underground stems, so it can form larger patches over time if left unchecked. However, it is not usually considered an invasive species in most regions because it tends not to aggressively displace other well-established plants. To prevent unwanted spread, you can deadhead the flowers before they set seed and divide the clumps every few years. These measures will keep yarrow contained to the desired area.
Should I cut back yarrow after it blooms?
Yes, it is beneficial to deadhead yarrow once the blooms fade. Trimming off the spent flower clusters will tidy up the plant and often encourage a second flush of blooms later in the season. In addition, yarrow stems can be cut down to the basal leaves in late fall or early spring as part of general garden cleanup. This helps the plant direct its energy to new growth and prevents the old stems from becoming messy.
Can yarrow grow in shade or in pots?
Yarrow prefers full sun and will bloom most abundantly with plenty of light. It can tolerate partial shade (especially in hotter climates), but in too much shade the plant tends to become leggy and produce fewer flowers. As for containers, yarrow can be grown in a large pot provided it has very well-draining soil and plenty of sun. Just be aware that in a pot, yarrow’s spreading roots might become crowded over time, so occasional division or an extra-large planter is needed.
Is yarrow poisonous to pets or people?
Yarrow is only mildly toxic. If pets (such as dogs or cats) chew on it, they could get an upset stomach or start drooling. Luckily, animals usually find it unpalatable and avoid eating much. For people, yarrow isn’t considered poisonous in small quantities (it has even been used in herbal teas), but it’s not meant for casual consumption and can cause skin irritation in some individuals. It’s best to keep pets from grazing on yarrow and to handle the plant with gloves if you have sensitive skin.
How do I keep yarrow from flopping over?
To prevent flopping, make sure your yarrow is getting enough sun and not too much fertilizer or water. Plants grown in rich soil or shade tend to grow taller and weaker. You can also trim the stems back by one-third in late spring (before flowering) to encourage a sturdier, shorter plant. When grown in ideal conditions (full sun, lean soil), yarrow usually has strong stems, but after heavy rain it may still topple. In that case, using small stakes or plant rings for support can help prop it up.
How long does yarrow bloom and does it rebloom?
Yarrow typically blooms from early summer through mid to late summer. Many varieties will start flowering in June and continue into August. By deadheading the first round of spent blooms, you can often get additional clusters of flowers later in the season. While it may not bloom continuously all summer without pause, with some simple maintenance yarrow will provide color for an extended period of the growing season.
Does yarrow attract bees or butterflies?
Yes. Yarrow is excellent for pollinators, and its flat-topped flower clusters are particularly accessible to butterflies, which often land on them to feed. You will also see many types of bees (from honeybees to native solitary bees) visiting yarrow blossoms for nectar and pollen. Moreover, yarrow’s blooms attract beneficial insects like hoverflies and predatory wasps that can help control garden pests. In short, yarrow is a very pollinator-friendly plant.
Interesting tips
- Plant yarrow near roses or other pest-prone plants to attract ladybugs and other beneficial insects. Yarrow’s presence can help naturally reduce aphid infestations and other pests on neighboring plants.
- Yarrow can be used as a lawn alternative or groundcover in low-traffic areas. It tolerates some foot traffic and requires far less water than a traditional grass lawn once established.
- For a second flush of flowers, shear yarrow plants back by about one-third after the initial summer bloom. This pruning encourages fresh growth and often results in additional blooms later in the season.
- The genus name Achillea comes from the Greek hero Achilles, who according to myth used yarrow to treat his soldiers’ battle wounds. This legendary use earned yarrow folk nicknames like “soldier’s woundwort” over the centuries.