I wish I were more like Holly…wandering around nurseries finding pretty and unusual annuals and perennials to get excited about. Instead, I seem to gravitate to plants that annoy me.
Today while looking for some trellises (for those containerized Clematis vines that I’ve been torturing) I saw pots of the Equisetum hyemale (“a tall, evergreen, spreading, reed-like grass”) for sale:
As readers of this blog surely know, Equisetum spp. – or horsetails – are not grasses but primitive relatives of ferns. That taxonomic blunder aside, the thought of deliberately planting any Equisetum species in a landscape sends shivers down my spine.
Now E. hyemale is not as weedy as E. arvense, but in nearly every seminar I give on controlling weeds with mulch someone asks about getting rid of horsetails. Short answer – you pull. And pull and pull. There’s no good herbicide for them, nothing seems to eat them, and they spread aggressively.
And speaking of eating, did you know that horsetails are poisonous? They contain an enzyme (thiaminase) that deactivates thiamin (vitamin B1) in the unfortunate consumer’s body. The most common victims of horsetail poisoning, ironically, are horses. Horsetails are considered noxious weeds in pastures used for grazing – and yes, they are native to the United States.
Sure, horsetails are interesting looking plants. But do you really want something in your garden that the production nursery describes as having “indefinite spread?” And how does keeping them in a pot, as one production nursery recommends, keep them from spreading spores? Especially if you plant them “in or around ponds and streams?”
I just think this is such a bad idea for home landscapes. Even if it is a native species.