Is Yarrow Invasive?

Yarrow (Achillea millefolium) is widely appreciated for its delicate, fern-like foliage, clusters of long-lasting blooms, and benefits to pollinators and soil health. However, many gardeners ask the same question: Is yarrow invasive? The answer is nuanced.

While not classified as invasive in all regions, common yarrow can behave invasively, spreading aggressively in favorable conditions through both rhizomes and seeds. Understanding which varieties of yarrow grow aggressively, how yarrow spreads, and how to control it, is essential for keeping it a healthy part of your garden.

Understanding Yarrow's Spreading Habits

Yarrow spreads through two main mechanisms:

  • Rhizomes: These underground stems extend horizontally on top or beneath the soil and send up new shoots at regular intervals. This allows the plant to form a dense mat of growth over time.

  • Seeds: After flowering, common yarrow produces large numbers of tiny seeds that are easily carried by wind, water, or even wildlife to new areas. However, not all yarrow produces fertile seeds.

This dual method of reproduction makes common yarrow a vigorous and sometimes aggressive grower, particularly in environments where it faces little competition.

How Fast Does Yarrow Spread?

In ideal conditions, common yarrow can quickly colonize large areas of soil. In just a few seasons, it can move far beyond its original planting site and begin overtaking nearby garden beds, lawns, or wild spaces. Its quick growth makes it excellent for ground cover and erosion control, but without active management, it can crowd out neighboring plants and dominate space not originally intended for it.

What Makes Yarrow Invasive?

One reason yarrow can behave invasively is its extreme adaptability. It thrives in a wide range of soils—including poor, sandy, or rocky conditions—and tolerates drought, heat, and light frost. In areas with low competition or disturbed soil, common yarrow's growth can become unchecked.

Favorable Growing Conditions

Several environmental factors contribute to yarrow’s tendency to spread rapidly and aggressively. Well-drained, low-nutrient soils give it a distinct advantage over more delicate or nutrient-demanding plants, allowing it to thrive where others struggle. In dry climates, yarrow tends to expand even more through its underground rhizomes, forming dense patches that can be difficult to contain. When left unpruned, the plant easily self-seeds, as mature flower heads disperse seeds that quickly colonize surrounding areas. Additionally, in gardens or landscapes with minimal competition from neighboring vegetation, yarrow can dominate the space, outgrowing and outcompeting less aggressive species.

Regional Context Matters

While not universally classified as an invasive species, Achillea millefolium is considered invasive or aggressive in several regions. In parts of North America, particularly in prairies, grasslands, and disturbed meadows, common yarrow can outcompete native species and disrupt plant diversity. Similarly, in countries like Australia and New Zealand, it has spread in natural areas where it wasn't originally present, raising concerns about ecosystem disruption.

Signs That Yarrow May Be Getting Invasive

If you’re growing yarrow in your garden, here are signs to watch for:

  • Rapid ground coverage with few breaks between plants

  • Displacement of surrounding vegetation due to competition for nutrients and light

  • Persistent regrowth from rhizomes even after removal efforts

  • Unwanted seedlings sprouting in other garden areas or nearby natural landscapes

These symptoms suggest that yarrow is starting to move beyond ornamental use and becoming harder to manage.

How to Control Yarrow’s Spread

If you're concerned about yarrow overtaking your garden or spreading into surrounding areas, there are several effective ways to keep its growth in check. With a combination of smart maintenance practices, physical barriers, and careful plant selection, you can enjoy the beauty and benefits of yarrow without dealing with its more aggressive tendencies.

Prune Regularly

One of the simplest and most effective ways to limit yarrow’s spread is by consistently removing flowers before they go to seed. Because of Yarrow’s growth habit, deadheading is not recommended. However, pruning spent flowers is. Removing the mature flower and its stalk to the basal foliage serves a two-fold purpose. First, you will remove spent flowers before they go to seed. Second, trimming yarrow after flowering will help limit the plant’s size. Note also that yarrow makes good cut flowers and great dried flowers … if you’re into that kind of thing.

Cutting Back Rhizomes

Rhizomes are modified stems, not roots, that contain internodes (aka, nodes). These nodes can result in both roots or shoots for new plants. The rhizomes can either spread on the surface or just below the surface. Cutting back rhizome runners also helps to contain horizontal expansion.

When new plants with their own basal growth magically pop up beside your original plant, this form of asexual reproduction results from rhizomes. This new, unwelcome plant is completely self contained. It can be removed, without harming your original plant, by severing the rhizome connecting it and then can be replanted elsewhere or disposed of as a weed. After all, a weed is merely a plant out of place so if achillea expands beyond its acceptable boundaries, it becomes a weed and should be disposed of accordingly (or transplanted elsewhere).

Use Physical Barriers

To stop underground rhizomes from creeping into unwanted areas, consider installing physical barriers such as landscape edging or root-blocking fabric. These barriers should be buried 6 to 12 inches deep to be truly effective. This method is particularly helpful in garden beds where yarrow is used for ground cover but needs to be kept within defined borders.

Mulch can be a powerful tool for suppressing Achillea (yarrow) seed germination. Not only does mulch prevent the seeds from making direct contact with the soil, but it also prevents sunlight from reaching any new seedling growth. 

Choose Non-Invasive Cultivars

Achillea millefolium, or common yarrow, first took root in American soil centuries ago, arriving with early settlers and quickly naturalizing across the continent. Its original form—white-flowered and wild— passed from plot to plot with its tenacious spreading habit and ability to thrive in poor soils with minimal effort.

In contrast, today’s cultivated yarrow hybrids offer a more refined experience. Bred for stronger stems, upright habits, and larger, longer-lasting blooms, these modern selections display far more controlled growth. Some are even sterile, eliminating the self-seeding and aggressive spread typical of their ancestral counterparts. For gardeners seeking beauty without chaos, these hybrids strike the perfect balance between ornamental charm and disciplined performance.

We recommend three commonly found hybrids if you are concerned about potential invasiveness:

Coronation Gold

  • Colors: Gold with silvery foliage

  • Height: 24-36” Height, 18-24” Width

  • Seed: Sterile

Little Moonshine

  • Colors: Yellow with silvery foliage

  • Height: 9-14” Height, 10-16” Width

  • Seed: Sterile

Moonshine

  • Colors: Yellow with silvery foliage

  • Height: 18–24” Height, 24-36” Width

  • Seed: Sterile

Preventing Invasive Spread in Natural Areas

To minimize ecological impact, avoid planting common yarrow in wild or open areas such as meadows, prairies, or near natural forests. These settings allow common yarrow to escape cultivation and potentially outcompete native plants. Keep yarrow confined to managed garden beds where it can be monitored.

Monitor and Act Early

Frequent monitoring is key to managing yarrow effectively. Watch for signs of unwanted spreading, especially near the edges of planting areas. If you see new shoots emerging beyond their intended space, dig them out promptly. Mulching well also helps to limit aggressive growth. Addressing spread early prevents larger problems down the line.

Consider Native Alternatives

If you're looking for pollinator-friendly perennials with similar benefits but less risk of invasiveness, consider native alternatives such as goldenrod (Solidago spp.) or coneflowers (Echinacea spp.). These plants provide nectar, support biodiversity, and offer a similar aesthetic without the spreading concerns associated with yarrow.

Enjoy Yarrow Responsibly

Yarrow is a beautiful, low-maintenance perennial with immense value for pollinators, erosion control, and ornamental design. But with its ability to spread rapidly through rhizomes and seeds, some types of common yarrow can become invasive under the right conditions. By selecting well-behaved cultivars, planting responsibly, and using preventive techniques like pruning and root barriers, you can enjoy the benefits of yarrow without letting it overtake your garden or nearby landscapes. With thoughtful management, this classic plant can be a sustainable and eye-catching part of your garden for years to come.