Reverse Invasion of the Body Snatchers!
ARG! … Horse Tails!! They’re everywhere! It’s like every enemy or monster I ever thought of or had nightmares about has been spirited into a horsetail “body” and sent to my little plot of Ocean Shores to invade, choke, and destroy every plant or blade of grass that I tried to grow here! @#$%&*!!!! And to think that once upon a time, I thought them intriguing enough to take one from my Ocean Shores summer home and transplanted it into my lush and lovely Renton garden! But it wouldn’t grow in such a nurturing environment.
Ok, so lets get a reasoned head and take a look at this creature.
Genes: Equisetum: common name: Horsetail. This is an ancient plant, closely related to ferns. At the time of the dinosaurs, many species filled in wastelands, with one variety growing 90 FEET tall! They haven’t changed much, although today only 20 species are left, with two persistent ones in Ocean Shores.
E. arvense (Common Field Horsetail.) This is one of the most widespread and common plants in the world. It prefers wet forests, meadows and swamps, but will grow almost anywhere, not needing many nutrients. The young fertile shoots that come up in the early spring are edible. Ancient Romans also powdered these and used them as a tea or a thickening agent. The sterile shoots, which one finds during summer, however, are toxic to most mammals. (The deer know this.) These can be used in an emergency to stop bleeding and heal wounds.
E. variegatum (Northern Scouring-Rush Horsetail) a shorter variety of the more widely distributed, E. hyemale (Scouring Rush Horsetail.) This species is shorter, stalkier and less feathery than the arvense. Although both varieties absorb silicon dioxide (a major component of sand and glass) variegatum has more, making it rough and tough. The Tlingit and Coastal Salish tribes of the area used the sterile shoots to scour cooking utensils and polish wooden artifacts. I have used these to clean out pots on camping trips. It works!
Like ferns, all horsetail species produce two types of stalks. The fertile stalks, appear in early spring, look like asparagus with joints in the stem, and carry a spore-producing cone at the top. The vegetative stalks of summer are sterile, but chlorophyll in the stems and branches helps photosynthesize the products that keep the entire plant alive.
Horsetails are pioneer plants rather than weeds. They are first to fill in after any kind of land devastation that destroys the productivity of the soil: floods, earthquakes, landslides, volcanic eruptions… E. arvense was the first vascular plant to reach up through Mount St Helens ash, just a few months after the May, 1980 eruption. All horsetails thrive in poor, especially sandy soil lacking in nutrients.
Not only are they the first plants to populate an unhospitable area, but they are survivors. Coming to us, unchanged from the Carboniferous period, more than 300 million years ago, they are thought to be the oldest surviving genus on Earth (forgotten knowledge from one of my college Botany texts, including one I taught from!) Tenacious little critters! Thank goodness we don’t have any of the 90-foot variety to worry about.
OK, so they like sandy, acidic, nutrient poor soil that would starve most other plants. They have long meandering roots (up to 2 meters, both deep and wide.) They can push through compacted soil. They can break through cement! They cope well with dry seasons or climates, but they don’t mind high water tables that can waterlog their roots. They reproduce, like ferns through spores, and their rambling roots that grow new plants wherever they can (especially if they have been broken by ambitious garden weeders.)
They are hard to get rid of. If you pull them up, the roots break, encouraging new plants to grow from each break. You would have a better chance digging down at least a foot to get the entire root. Chemicals can kill the above ground parts but have to be injected into each root to be effective at all, and usually the plant exudes whatever chemical you use into the surrounding ground to kill other plants in your garden. They prefer acidic soil, so sometimes adding dolomite lime helps, although most of our native or deer resistant plants also prefer slightly acidic soils. When planting lawns, choose grasses that like more alkaline soils and don’t mind our salt air. Horsetails thrive in compacted, low oxygen soils so sometimes aerating the ground helps.
But they wouldn’t grow in my lush, humus-filled, organically fertilized garden in Renton. And that is the key. It’s about the soil and filling up your landscape space with healthy plants to out-compete the horsetails.
The best advice I could find is a two-pronged approach. When the fertile stalks appear in the spring, CUT them (do not pull them) before the spores mature to prevent new plants. When the vegetative stalks appear in the late spring and summer, wait until they are about three inches high and CUT, mow, or weed-eat them, to prevent broken roots from sending up new shoots. Some will reappear in about three days, so you will need to be vigilant and keep cutting the three-inch plants to prevent feeding the roots. If this is all you do it might take three to five years before the plants are starved.
The second attack is to change the soil and plant environment. Bring in new topsoil. Add organics: compost, humus, horse or chicken manure. Plant shrubs and ground cover that prefer more alkaline soil. Lawns are a good idea, but take care to select grasses that can survive our wind and salt air. Make sure your soil drains properly to prevent standing water either above or below, ground. Water appropriately, especially July through September.
All that is a LOT of work. But that’s what I am trying to do with my totally soil-scraped patch of sand around my newly build home. It’s labor-intensive and expensive. It’s a good thing King County house values were high when we sold. I also couldn’t do this without my wonderful gardener!
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For questions, comments about this article or to share your gardening experiences, please contact Dauna at: dauna@gardenbytheseaoceanshores.org
This article was originally printed in The Ocean Observer, August 2020.
