One gardener’s thug is another gardener’s bonus.  A gardener friend of mine cautioned against planting any purple shiso (Perilla frutescens) in my garden.  “It will self-seed everywhere and soon be a pest,” she admonished.  She, of course, was right.  It does self-seed, but to my mind appealingly so.  The dark purple ruffles rival any coleus.  Another benefit, other than the appealing splotches of deep color, is that shiso can be used in cooking.  Although it has wandered into some of the lawn grass, husband just mows down anything that encroaches on his turf.  So far, no problems, just pretty purple ruffles along the bed edges.

Wild perennial ageratum (Eupatorium coelestinum) is another welcome wanderer.  Its seed searched out every spot of earth in my shaded garden areas.  Boy, did it go forth and prosper!  One thing about this hooligan, it is very easy to pull up.  And I don’t know of anything that compares to the drifts of blue this tall ageratum adds to the garden in the fall.  My fall garden would be dull, dull, dull if it weren’t for these blue clouds of ageratum.

Wood violets (Viola riviniana) are another story.  Their tiny flowers are harbingers of spring and perfect nosegay bouquets.  Children love them.  So do grownups like me, who remember them fondly from springs past.  When their violet or white or blue faces appear, spring can’t be far behind.  They are a nuisance in bare garden areas and even in lawns.  Unlike the ageratum, they have rhizomes that run across the top of the soil with roots that must contain super glue.  If you try to pull them up, the heart-shaped green foliage comes away, leaving the rest of the plant to sprout again when your back is turned.

Elephant ears (Alocasia or Colocasia)!  If you have a wet spot and live in the south, they will love you forever.  Bulbs are usually planted in dry soil.  Not these tender big boys.  They like it wet and will reward muckiness with more bulbs.  Elephant ears will be coming out of, well you know as the saying goes, your ears.

Bananas (Musa) are another muck-lover, although they are not quite as particular about having wet feet.  They will take some dry ground.  If they are happy with you and your soil, either potted or in-ground, they will send up lots of banana babies (called pups) for friends.  If you are really lucky, you will get a hand or two of banana fruit.  (Bear in mind, though, that some varieties of Musa are purely ornamental and don't produce edible fruit.) Just keep those lovely long leaves out of the wind or they will soon be shredded.  Shredded bananas are not a pretty site.

Lily of the valley (Convallaria majalis), although touchy in the south, will populate a northern shade garden and then if it finds itself confined, will double back on itself.  The white bells full of sweet scent make cultivating a population worthwhile.

Northern sea oats (Chasmanthium latifolium) is a native grass that is prolific, much more so than its beachy, dune loving cousin, wild sea oats (Uniola latifolia) which is a protected species in most coastal states.  The northern sea oats grass has wands of dangling flat seed heads that dance along the wiry stems.  They will seed most anyplace, next to each other or in a pathway between bricks.  To keep them in bounds, harvest the eye-catching seed heads for your fall and winter dried bouquets.

Some seed and root spreaders should not be planted because of the damage they can do if they get loose in woodlots or waterways.  Purple loosestrife (Lythrum salicaria), a true thug busy eating up coastlines all over the U.S., jumps to mind. These prolific growers can wreak havoc on wild natives, choking them out and decreasing the diversification we need in the plant world to keep it, and us, healthy.  The USDA (http://plants.usda.gov/java/noxiousDriver ) has invasive species listings for each state.  Before you bring home a thug, make sure it will not be spread to wild areas.  Birds, wind, even raccoons can be carriers of seeds to places they should not spread.

Unfortunately, many of our natives--so well behaved in their native habitat--can become thugs in cultivated gardens.  More and more hybrids are sterile.  No seeds mean no free plants and no fun for the gardener trying to fill every little patch with color.  Give me the old-fashioned thugs that plant themselves.  They are healthful additions to my garden.  I can put away hoe and shovel.  They save my back.

---Posted by Anne K Moore June 23, 2008---