Watch Out! These Invasive Weeds Can Camouflage as Flowers in Your Garden
For some gardeners, there's beauty to be found even in weeds, which are a group of plants that are labeled harmful purely by human distinction. Experts at Wave Hill, a public garden and horticulture center in New York, say that most weeds share the same qualities of other perennial garden favorites that we know and love. Weeds do flower, as well as yearn for sun and water, and have the ability to grow seasonally each year, too. "What makes a weed is very context dependent with geography, land use, and personal preferences," says Steven Conaway, Wave Hill's assistant director of horticulture. "Even Emerson once famously said, 'What is a weed? A plant whose virtues have not yet been discovered.'"
But Conaway admits that weeds can be downright dangerous in a home garden, and the most devastating varieties know how to camouflage themselves among other plants and flowers that you've taken the time to grow yourself. "These weeds compete for sunlight, space, water, and soil nutrients. Some weeds further antagonize other plants by releasing chemicals that inhibit the growth of their neighbors; a phenomenon called allelopathy," Conaway says. Experts say that weeds often grow in the same area each and every year. "Gaining a familiarity with the specific weeds in the garden is also the best way to anticipate where weed problems will occur in the future, and where to concentrate your weeding effort. The best indication of where you will find weeds next year is where you see them now," Conaway says.
The following pervasive weeds have been identified by a team of experts at Wave Hill, including Conaway; Louis Bauer, senior director of horticulture; and Charles Day, the Ruth Rea Howell senior director of horticulture. They're also naming the plants that they could be mistaken for as well as share the best way to prevent weeds from spreading in your garden at home.
How to Prevent Weeds
Frequently check your flower beds for them, Conaway says. Scoping them out in your garden and physically removing them is about the only way most home gardeners can prevent weeds without actually harming other seedlings, flowers, or shrubs. "Knowing about the lifecycle of specific weeds can allow you to better control them," Conaway says. "For example: Knowing that a weed is an annual, a gardener can target the flowers and seed heads to keep the plant from reproducing. The existing weeds will die at the end of the season."
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. 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, Wave Hill experts suggest planting it in a segregated planter where it can be easily contained.
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. 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.
This invasive weed species is often mistaken for wild poppies since their flowers are strikingly similar. But prickly lettuce can actually be quite harmful to pets and animals; it contains lactucarium, which is a natural sedative that actually causes animals to be frantic if ingested.
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 it's 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.
Convolvulus arvensis is often mistaken for morning glory or petunias, as this species produces full-bodied florals that are white—but 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.
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, and since it can thrive in a multitude of soils and conditions, it's important to remove the plant as soon as possible.
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. Heart-shaped leaves give way to distinctively bright yellow, glossy petals.