Some creep insidiously along the earth; others send subversive suckers snaking underground in spiteful directions; still others broadcast seeds with a perfidious knack for finding cracks and crannies from which their malignant offspring are impossible to extricate.
I’m not speaking here of weeds, of unwanted and unwelcome invaders. No, the monsters I have in mind are disloyal plants that we ourselves have introduced to our gardens, only to have them turn on us treacherously, rewarding our care by making our lives a misery.
Their numbers are legion and many a gardener can tell a woeful tale of having been overrun by what at first seemed a charming addition. Running bamboos are notorious in this regard, and there’s more than one unwary plantsperson has been run right off their place by bamboos running riot. English ivy has been known to infest entire forests and Scotch brrom to make a mess of perfectly lovely meadows.
But I also remember a friend gardening in moist ground who was brought near to her wit’s end by Creeping Jenny, Lysimachia nummularia, (all zones). A pretty little ground cover in the proper place, this little creeper loses all sense of perspective in rich, moist and shady conditions, running rampant over perennials and even small shrubs.
Suckering plants offer particular challenges. Early in our gardening career, Sandy and I introduced a Japanese angelica tree, Aralia elata, (hardy to zone 2), whose menacingly thorny limbs we were willing to overlook for the elegance of its large leaves and its cloud-like clusters of ivory flowers.
But within a year or two this angelic customer produced vigorous suckers, some several metres from the mother plant, that were hellish to root out. After a fierce skirmish, they’ve all been banned to a remote and wild corner of the garden.
The same can’t be said of comfrey, Symphytum officinale. It’s incredibly useful stuff for medicinal purposes and for activating compost heaps and sweetening the compost privy. But the plants are deep-rooted and indefatiguable in seeding. The Sunset Western Garden Book sounds a sensible alarm: "Although comfrey has a long history as food and as a folk remedy, think hard before establishing it in your garden. Plants spread freely from roots and are difficult to eradicate." Tell me about it. Once established, comfrey, like the poor, are always with us.
Two other useful and time-honoured plants, Lemon balm and Sweet Cicely, have their menacing sides as well. Our first-ever Lemon balm, Melissa officinalis, , seemed like a gift from the gods, so tasty were its lemony leaves in drinks, salads and fruit cups, so pungent in sachets and potpourris. But talk about a prolific seeder! We’ve got them everywhere now, and there’s no balm to be had from these lemony breeders.
Sweet Cicely, Myrrhis odorata, is the same. Oh, her ferny leaves and fragrant creamy flowers are sweet enough in rhubarb pies and salads, but let her seed and you’ll regret it. Like comfrey, she sends her white fleshy taproots deep into the earth, and if in trying to dig out an unwanted plant you leave even a scrap of root behind, back it comes even stronger than before.
Nevertheless, the suckering and self-sowing monsters are child’s play compared to the sinister spreaders that send roots and rhizomes and rooting branches in all directions. We have several of these menacing our place, and I fear they’re destined to claim it all in the end. Ground ivy, Glechoma hederacea, is one. We have a patch of it in the old goat pasture. I’m prepared to blame former neighbours for its introduction. Each year the patch expands, inexorably, like a cancerous suburban sprawl nothing can contain.
Worse still, perhaps worst of all, is a creeping dead nettle, Lamium galeobdolon ‘Variegatum’. Tidy and graceful enough when confined in hanging baskets, we planted a tiny patch of it in a cool, moist corner behind the house. Big mistake. The stuff is everywhere now, spreading with arms like tentacles, rooting as it goes and seeding freely elsewhere on the property.
Perched on the edge of some lovely native woodlands, I’m occasionally assailed by guilt that we’ve introduced these exotic invaders that will eventually overrun all local flora, leaving our names besmirched in local legend, like the geniuses who imported rabbits to Australia. Then I look around at other plants we’ve got -- Japanese anemones, spurge, Saint John’s wort, lily of the valley, even hellebores -- that also show alarming expansionist tendencies, and I realize that all is lost.
In weak moments I begin reconsidering the merits of 2,4-D. Watching wretched rhizomes and treacherous tendrils closing in on us, I dream of the life we might have enjoyed in a cozy little townhouse somewhere, with professionals looking after the landscape maintenance. Instead, this ignominious end. Farewell.