Never heard of thugs in the garden? You haven't hung around Dave's Garden quite long enough. Or been reading enough garden blogs; DG isn't the only place I found the term thug used.

Thug. Ruffian. Hooligan. Gangster. You get the idea. A plant that takes no prisoners. A plant with potential for being a huge pain in the asparagus.

At right - Spiderwort offers pretty flowers to distract you from its "thug" habits

"Garden thug" defined in Gardenology:" A nickname for plants that grow vigorously and choke out less aggressive nearby plants." To expand: A really interesting, pretty plant that grows so easily for you that you are suddenly overrun with it. A thug takes over. It respects no gentle boundary. It doesn't play nicely with your other flowers. It grows on top of, or right through, every other plant nearby. Because a thug is pretty or interesting, you can't stuff the plant in the yard waste bin and forget it. You feel compelled to share it with (inflict it on) your fellow green thumbs. It's OK, you tell yourself. Thuggishness can vary (just like "your mileage.") But for the most part, for most gardens, thug "thuggishness" varies, from a little thuggish and a lot thuggish.

How do plants take over?

Rhizomes, super sneaky method of garden domination - Some thugs make underground stems called rhizomes. Rhizomes grow under the surface of the soil, or under mulch, or under shallow edging. They can grow right into the root mass of neighboring plants.

Seeds, scatter bombing your yard - Some plants make a million seeds that are very good at growing without your help. These seeds fly for a surprising range and lay in wait until you least expect them.

Stolons - not so sneaky, but just as deadly, the plant grows along the top of the soil. Stolons from thugs can wind their way between, and right through, their bedfelllows.

Agressive garden thugs don't appear on lists of invasive plants

Thugs are not the primary focus of articles about "invasive plants." The term invasive is most often used to mean plants that

  1. are so aggresssive that they've escaped cultivation in a big way
  2. have come from an entirely different region
  3. have been widely and officially documented

Kudzu is well known as invasive, but probably won't be called a thug because no one would dream of trying to keep it in a garden. Many of our weeds are also non-native invasive plants. Aggressive garden thugs are not necessarily included on lists of "invasives" or "noxious weeds." Thugs don't always seek WORLD domination, it's just that once invited to your garden they act like bullies. And native plants that are valuable in the wild CAN be garden thugs. (Asclepias syriaca, I'm talkin' to you...)

Most wanted (unwanted) list of thugs

close view of mint plant

  • Bamboo (the running types)
  • Mint (Mentha)
  • Ivy (Hedera)
  • Artemisia, some cultivars
  • Bishopweed (Aegopodium podograria)
  • Chameleon plant (Houttuynia cordata)
  • Lamium galeobdolon
  • Spiderwort (Tradescantia)
  • Lysimachia, some cultivars
  • Morning glory (Ipomoea)
  • Miscanthus

Thug avoidance tips

Know your plant - Grow a new plant for at least a full year, better yet two or three years, before professing to know all its habits. Thugs can sleep and creep for two years before leaping over the fence or across the sidewalk. Watch for seedlings, runners, rhizomes and stolons.

Research your plant - Look it up in Dave's Garden Plant Files, where you'll read real feedback. These gardeners are not shy about telling you when plants make them unhappy. Just as important, they can tell you what conditions bring out the thuggishness of the plant, and whether the redeeming values ever make the struggle worthwhile.

Beware the boxful - Beware when taking a new, unfamiliar plant that someone offers by the boxful. These generous gifts are often gilded with statements like "it is really tough, I just rip it out, I'm sure it'll grow for you, and I have so much I had to get rid of some of it... "

Go forth gardeners, and share plants! By and large, plant swapping is a fabulous wonderful thing. But keep thuggishness in mind. Be honest when offering thugs, be cautious in accepting them, and we'll all have an easier time maintaining our green spaces down the road.