Yarrow: Invasive Or Not?

Yarrow is widely appreciated for its delicate, fern-like foliage, clusters of long-lasting blooms, and benefits to pollinators and soil health. Also, known as Achillea, this perennial is one of our favorites here at Garden Delivery. Many gardeners ask the same question about Yarrow: Is it 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.

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By: Reggie Meehan (7/26/25) - Last Updated (2/3/2026)

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.

Yarrow Can Spread Quickly

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 Spread More Than Expected

Favorable Growing Conditions

Yarrow actually prefers lean, well-drained soils, which means it often grows faster than more nutrient-hungry plants around it. In dry climates especially, it spreads steadily through underground rhizomes, knitting together into dense patches that don’t leave much room for neighbors. If flower heads are left in place, it will also reseed itself freely, filling in open spaces surprisingly quickly. In gardens with wide spacing or bare ground, it doesn’t take long for yarrow to become the dominant plant in the area.

Regional Context Matters

Yarrow isn’t considered invasive everywhere, but common yarrow (Achillea millefolium) has earned that mark in certain regions. In parts of North America, especially prairies, grasslands, and disturbed fields, it can outcompete native plants if left unchecked. It's become concern in places like Australia and New Zealand, where it wasn’t originally native and has spread into natural areas. 

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 Keep Yarrow in Its Place

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. A little bit of regular maintenance goes a long way. With thoughtful pruning, occasional root work, and some simple boundaries, you can enjoy everything Yarrow has to offer without letting it take over.

Prune with Intention

One of the most effective ways to slow Yarrow down is to stay on top of the flowers. Rather than deadheading individual blooms, I always cut the spent flower stems all the way back to the basal foliage once they’re finished. That does two things at once—it prevents the plant from setting seed, and it keeps the overall size in check so it doesn’t get leggy or oversized.

This is also a great time to enjoy Yarrow as a cut flower or to hang a few stems to dry. I’ll admit, I don’t dry as many as I used to, but it’s nice to know those prunings don’t have to go straight to the compost pile.

Cut Back the Rhizomes

Yarrow spreads underground through rhizomes, which are actually modified stems, not roots. These runners travel just below the soil surface and can send up new plants a short distance from the original clump. If you ever notice a new little Yarrow popping up nearby, that’s usually what’s happening.

The nice part is that these offshoots are easy to deal with. You can simply sever the rhizome connecting it to the main plant and lift it out without harming the original clump. Sometimes I replant them elsewhere; other times, I remove them altogether. A plant out of place is still a weed, even if it’s a beautiful one, and there’s no harm in treating it that way when it crosses a line.

Use Physical Boundaries

In areas where Yarrow is acting as a ground cover or filling in larger beds, physical barriers can be helpful. Simple landscape edging or root-blocking fabric, buried about 6 to 12 inches deep, does a good job of keeping rhizomes from creeping where they don’t belong. I find this especially useful in mixed beds where Yarrow needs to stay within a defined space.

Mulch also plays an important role. A good layer of mulch helps prevent Yarrow seeds from germinating by blocking light and keeping seeds from settling into the soil. It’s one of those quiet, behind-the-scenes tools that makes managing Yarrow much easier over time.

Choose Non-Invasive Cultivars

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.