6 Fast-Growing Plants That Can Quickly Crowd Out Everything Else, Even If They’re Not Invasive

Resilient plants that will reliably and quickly cover a hard-to-fill slope or shady spot are appealing. However, some vigorous growers can quickly spread beyond the space you designated, sometimes overwhelming neighboring plants or even entire beds.

However, that doesn’t mean you shouldn’t grow them. The key is understanding when and where to plant them and how to manage their growth so they don’t completely take over your yard.

Below are some popular fast-growing plants that can crowd out everything else, but don’t have to.

Bamboo

Bamboo is a popular, fast-growing plant often used to create dense, tall privacy screens and stabilize slopes prone to erosion. However, it’s one of the most famously aggressive spreaders in garden landscapes.

Running varieties of bamboo—like golden bamboo (Phyllostachys aurea—spread through underground rhizomes that can travel several feet each year. They send up lots of new shoots far away from where you put the plant originally, making them difficult to control once established.

If you want to prevent these rapidly spreading, consider physical containment when planting. Regularly cutting back new shoots as they appear is a helpful management technique, but growing in containers, installing deep root barriers, or digging trenches are important long-term strategies for keeping the rhizome spread under control.

Common Holly

Common or English holly (Ilex aquifolium) is an attractive evergreen shrub with glossy, dark leaves and bright red berries, synonymous with Christmas. It’s popular for hedging and winter interest, thrives in both shade and sun, and is adaptable to a wide range of soils.

However, this type of holly can spread aggressively in the right conditions, crowding out native species and stealing limited groundwater. The birds that eat the berries widely disperse the seeds, meaning you can find new shrubs establishing themselves in unexpected, often undesirable places in your (or your neighbor’s) yard.

Remove unwanted seedlings as soon as they appear and to avoid letting berries drop freely around your yard. Regular pruning also helps to control this vigorous shrub’s size and density.

Japanese Anemone

Japanese anemones (Eriocapitella x hybrida) are popular, elegant fall-flowering additions to cottage or woodland wildflower gardens. They thrive in partial shade and provide a splash of color after many other perennials have finished blooming.

However, beneath their delicate-looking appearance, these plants have a vigorous spreading habit. Established, dense clumps expand through underground roots that can take over your garden beds if you’re not careful.

Regularly dig up straying shoots and divide dense clumps every few years. It’s all about being careful to remove as much of the unwanted root system as possible. If you leave even a small fragment, these exuberant plants will inevitably pop up again.

Leyland Cypress

Leyland cypresses (Cupressus × leylandii) are popular, fast-growing, hardy hedges for privacy screening.

However, don’t underestimate how their rapid growth can quickly become a problem in your yard. These evergreen hybrid conifers can grow over one meter per year; these unwieldy heights cast heavy shadows over the rest of your plants and means they are aggressively sucking up available water.

They’re not a good choice for small yards; even when you have a lot of space they need careful management—regular pruning and a sensible planting position. Plant them at least 10 feet apart and far away from homes, walls, and fences. Thinning is also necessary to prevent disease from poor air circulation.

Lily of the Valley

What’s not to love about the sweetly fragrant little white blooms of the popular woodland perennial lily of the valley (Convallaria majalis)? These plants make for a charming, dense, lushly green ground cover that can thrive in deep shade.

However, the aggressively spreading, difficult-to-remove underground rhizomes create thick mats that can crowd out less resilient species.

Plant this long-lived, robust species in isolated, bare spaces in your yard. Using physical underground barriers that extend at least 6 inches into the ground, or growing in containers, also helps prevent it from spreading across the rest of your landscape.

Mint

Mint (Mentha spp.) is a low-maintenance herb that thrives in a variety of conditions and is beloved for its culinary uses, aromatic fragrance, and ease of growth. However, the underground runners rapidly send up new shoots that can take over entire beds if you leave them unchecked.

The best way to manage mint is to never plant it directly in the ground. Instead, grow it in containers or raised beds to keep its unruly roots contained, or sit some pots on your windowsill.

If you want mint to sit in a bed, sink the pit into the soil; this helps to create a barrier to prevent the runners from causing problems for other plants.