15 Invasive Weeds That Are So Pretty, You Might Mistake Them for Flowers

Common Purslane

Officially known as Portulaca olercea, this weed is commonly referred to as "moss rose"—but most gardeners are actually referring to Portulaca grandiflora, or ornamental portulaca, instead of this variety.

Portulacas are perennial succulents, and they require very little maintenance to begin with, but purslane can easily overtake your garden as its known to outgrow most spaces quickly. To prevent purslane from competing with other crops in your garden, try planting it in a segregated planter where it can be easily contained, says Wave Hill horticulture experts Conaway, Louis Bauer, and Charles Day. However, purslane is also edible, points out Seth L. Flanigan, senior natural resource specialist in invasive species at the Bureau of Land Management.

Weedy Amaranth

Amaranth is one of the most eye-catching additions to any landscape, as it's usually bright crimson—but unless it's ornamental in nature, it can quickly become unmanageable, say the Wave Hill experts. The weed variety is called Amaranthus albus, more commonly known as pigweed or tumbleweed, and isn't red whatsoever.

Just like the tumbleweeds that you find in the desert, weedy amaranth will spread its seeds by breaking off at the stem and tumbling throughout your garden, experts say.

Prickly Lettuce

This invasive weed species is often mistaken for wild poppy since its flowers are strikingly similar. But prickly lettuce can actually be quite harmful to pets and animals, says Wave Hill; it contains lactucarium, which is a natural sedative that, when ingested, causes animals to become frantic.

Trumpet Vines

Because its flowers are so beautiful, many home gardeners introduce or allow trumpet vines to say in their yards without realizing how invasive it is—or its capabilities to stifle younger seedlings in your outdoor space.

This vine produces seed pods which can then spread hundreds of seeds across your garden. The vine's tendrils spread quickly and can choke even old, established trees, warn the Wave Hill experts.

Before deciding to rip out the trumpet vines in your garden, though, compare them to your area's native plants. "There are some native trumpet vines or honeysuckle that are great to have in a garden," says Flanigan.

Field Bindweed

Convolvulus arvensis is often mistaken for morning glory or petunias, as this species produces full-bodied florals that are white—but Wave Hill experts say true morning glory flowers are normally blue, while petunias are available in a variety of hues.

Bindweed is rather tough to remove, Bauer says; you'll need to physically mow and pull all vines of the weed when they appear, and spend at least one season drying out the soil as much as possible before you plant again.

Tree-of-Heaven

When young, this fern-like weed can be quickly mistaken for ornamental sumacs or native sumac, which produce vibrant red, berry-shaped flowerheads. What starts as a young seedling with few leaves can actually grow into a full-blown tree, warn the Wave Hill experts, and since it can thrive in a multitude of soils and conditions, it's important to remove the plant as soon as possible.

Celandine

In rural areas, it's easy for lesser celandine (Ficaria verna) to grow into manicured areas, and when it flowers, it can be mistaken for marsh marigolds, says Wave Hill. Heart-shaped leaves give way to distinctively bright yellow, glossy petals.

Poison Hemlock

Even in tiny amounts, poison hemlock is highly toxic to animals and people. "People get it confused with wild carrot, aka Queen Anne’s Lace (Daucus carota)," says Marcus McCartney, agriculture and natural resources educator at The Ohio State University Extension. "As myth goes, it was a poison hemlock tea that was used to assassinate Greek philosopher Socrates."

Poison hemlock's "smooth, purple-spotted" stem sets it apart from wild carrot's hairy stem; hemlock can also grow as tall as 10 feet, while wild carrot peaks around 3 feet tall.

Multiflora Rose

Tiny, white multiflora roses, which are native to eastern Asia, are often planted as ornamental flowers or fence borders. The problem: They eventually grow into thick, dense clumps that spread, taking over green space and pushing out native plants.

"Stems that touch the soil are capable of rooting, roots not completely removed can resprout, and seeds can remain viable in the soil for up to 20 years," says Joseph Thomas, land stewardship manager at Longwood Gardens outside Philadelphia, Penn. Pull young plants by hand, or apply a basal bark herbicide to foliage and cut stumps, he says.

Cornflower

Flanigan suggests removing blue-purple cornflower, also called bachelor's buttons, which are herbaceous annuals in the same family (Asteraceae) as asters, daisies, and sunflowers. Though sometimes planted on purpose, they reseed quickly and take over fields and grassy areas.

Oxeye Daisy

Though other types of daisies are welcome additions to most gardens, oxeye daisy is one you want to watch out for, suggest Flanigan. It spreads aggressively by roots and seeds, leaving less space for a healthy and diverse plant ecosystem to thrive. Oxeye daisies are typically shorter than their Shasta daisy cousins and have smaller flower heads; they also emit a distinctive sage fragrance.

Yellow Toadflax

Yellow-and-white toadflax, which is also called wild snapdragon for its resemblance to the vibrant flower, is as invasive as its similar-looking cousin, Dalmatian toadflax. "Both are very showy," says Flanigan. The creeping roots allow it to push out the native plants favored by local fauna.

Purple Loosestrife

Perennial purple loosestrife is a water-loving plant that grows in wet environments. The showy purple flowers sit above complex intertwined root systems; according to the Minnesota Department of Natural Resources, mature plants can produce as many as 2.7 million seeds each year, extending their reach beyond manageable levels.

Autumn-Olive

"Bell-shaped flowers blooming in cream or pale yellow in early spring followed by red berries speckled with silver scales made autumn-olive an attractive ornamental choice in the 1800s when it was widely planted throughout the United States," says Thomas. Though planters believed the plants would benefit wildlife and prevent erosion, the autumn-olive instead took over precious space from native plants.

Thomas recommends pulling seedlings when you find them, and applying basal bark herbicide to stumps after cutting larger plants.

Yellow Flag Iris

These butter-colored flowers may look like a sunnier version of classic purple iris, but this aquatic plant spreads aggressively in wetland areas, taking up space where critical ecosystem supports, like cattails, could otherwise thrive.