Guest Article for the Tallahassee Democrat
Photo by Anne Tofield, Artemesia ‘lime light’
Friday, May 31, 2013
We have all made mistakes in our gardens. Some major, and others minor but how about those that are still infuriatingly there in spite of all efforts to get rid of them. These are plants that simply won’t go away. Most of them have some merit, I guess, but, they all are aggressive, defiant and resist efforts to eradicate them. These are not recognized invasives, but ordinary garden plants.
Asiatic Jasmine, for instance, can be a reasonable grass substitute if planted in a confined space. Maybe. Recommended as a no maintenance ground cover, it leapt away quickly and thickly by many spreading stems. It jumped beds and climbed trees. It has no known enemies and is impossible to dig up.
Shrimp plant, Justicia brandegean, a with salmon colored bracts, and yellow Pachystachys lutea were an unkempt nuisance at best. Early bloomers, they added color in a long bed that needed height. Alas, in a month they were tangled clumps of tall, thin, top heavy, stems which broke easily and then shot out in all directions. Digging them out did not work; they still come back every year.
Mountain mint, Pycnthemum muticam, a pretty greyish shrub is a conquering horror. One small cutting became an enormous shrub in three years in spite of judicious pruning and trimming. Its minty fragrance as well as its soft color lured me in, but it had to come out eventually. Even so, new plantlets continue to appear every spring after six years of dedicated combat.
I can’t decide which is worse: sharp and shiny sword fern or predatory Asiatic jasmine. They are both nearly impossible to eradicate. The fern, Nephrolepis cordifolia, is one of the many ferns which fall under the Boston fern umbrella. It invades any site by fast moving, shallow roots charging through anything in its path.
A few years ago a friend gave me six Physostegia Virginica. Commonly called obedient plants, they are anything but! I now have patches of them all over the garden. The flowers are very pretty, pale lavender that re-seed by the millions. When young they pull up easily, but sheer numbers make them impossible to obliterate.
A neighbor gave me five small calocassias 15 years ago assuring me they would not spread. They did. Most calocassias do and though mine pop up year after year, they have not jumped their bed. They are hard to pull up, impossible to dig up and resist any herbicide.
A four inch pot of Artemesia ‘lime light,’ a charming yellow and green ground cover, has drifted all over my two acres of garden beds. Similarly colored, low growing ardesia is another that won’t go away, appearing all over the garden. Ajuga reptans has its champions who like its dark leaves and blue flowers; it creeps slowly, and is not as predatory as the other two. Its effective, but I don’t want it anymore and there lies its danger. It resists all attempts at removal and some varieties will soon be on the invasive list.
I couldn’t wait to have an English dogwood, Philadelphus coronaria. I wish I had, my one plant has morphed into dozens which bloom beautifully, bend gracefully and smother anything near them. It multiplies very quickly and defies any controls.
Yellow iris and swamp sunflower, Helianthus angustifolius, also spread like a plague. The iris is reasonably easy to pull out but the pretty sunflower is hard to pull up with its coarse leaves, long roots and it sheds seeds by the gross.
Digging up is my preferred method of “removal”. In quotes because it doesn’t always work. One stray rootlet left in the ground can mean another plant next year. Glyphosate the active ingredient in Round-up is effective sometimes, but often not. Even so, constant removal efforts can halt some of the excessive growth. Best advice, research before you plant.
Anne Tofield is a Master Gardener volunteer with the Leon County Cooperative Extension Service and a member of the Leon County/UF IFAS Extension Urban Forestry/Horticulture Advisory Committee. For more information about gardening in our area, visit the UF/ IFAS Leon County Extension website at http://leon.ifas.ufl.edu. For gardening questions, email us at Ask-A-Mastergardener@leoncountyfl.gov