When we first begin gardening, our borders are so tidy, so orderly. Tall perennials in the center, cotton-candy branches of filipendula in spring, stalks of summer’s balloon flowers, autumn’s New England asters in deep purple and raspberry pink, surrounded with sunny clumps of coreopsis and later, the striking black-eyed Susans, stitched in with a carpeting rim of pastel creeping phlox early in the season, interspersed with cranberry saucers of sedum for the fall. And dirt, or the mulch we use to try to suppress the weeds, is very visible, and entails quite a lot of weeding.

Our intent, of course, is for those empty spaces to fill in, for those flowers to spread, seed themselves. We hear gardeners complain of overcrowding and the need to give away plants, and we look forward to that time, a time when our gardens will ripple from one end of the border and the season to the next with a steady stream of flowers. All at once this seems to happen. We notice that the leaves emerging in spring have grown to touch one another, the unfurling foliage of hosta, of columbine and lady’s mantle ruffles, plump mounds of catmint and candy tuft, tendrils of geranium, all stitching the garden’s edge together; and then the summer, when the bountiful flowers of daisies and lilies and bee balm have nothing between them except air. Perfection.

And then, another season, or a few, and we’re faced with a different condition – varieties which have grown rampant, trampling certain specimens, or in extreme cases obliterating them with their omnipresence, strength, exuberance, shall we call it – bullying? And we’re left wondering — why didn’t we see this coming? What happened to the primrose? The echinacea? The chrysanthemum? After several years of gardening, I have plenty of examples. In some places, I’ve promised to keep the rampant plants in perennial check. In other gardens, I’ve needed to eradicate the culprit completely. And in one case, I’ve been forced to give in to a plant’s aggressiveness.

There is only one artemesia that I find invasive – the variegated variety. It has its seasonal charm, yellow foliage striped chartreuse and lime to compliment lavender creeping phlox and daffodils. Shortly after this stellar performance, it reverts to green and spreads everywhere, so I mercilessly remove it, leaving a clump to return the following spring. This method of removal also applies to the ferns which have planted themselves beneath the butterfly bush. Because nothing else will grow there, I allow them to remain underneath the umbrella of silver-leaved limbs; however, their rapid encroachment on everything else forces me to continuously eradicate them throughout the season in this garden. Rampancy usually depends on the spot. Where the gooseneck loosestrife grows in the shade, it behaves itself, but it becomes obnoxious if it extends beyond that boundary and into the sun where it needs to be removed early, or late, in the season as I haven’t the heart to destroy it when it’s in bloom. Pervasiveness also depends on companions. I love the way that phlox swaps seeds, so that the original magenta, rose and white varieties now come in multiple shades of pink, and are perfect where they cavort with the equally rambunctious obedient plant, but not where they threaten the sedums and the daisies. The one plant I’ve given into is the variegated bamboo. Its vow to remain non-invasive lasted for over ten years, and then in one season it spread over the entire garden, leaving me time only to salvage the other flowers that were there. It’s really a lovely plant, with blades of gold and chartreuse which look attractive throughout the winter, so it has its own large garden now, circling the trunks of a willow, a hazel, and a golden dogwood, the only plants to survive its muscle.

There are some perennials that self-sow profusely which I can’t have enough of — mullein pink with its spurts of magenta, the balloon flowers that thoroughly transform the summer garden with their globes of indigo, mauve and shell pink, the lady’s mantle that extends its soft gray-green foliage and ephemeral chartreuse froth along the garden’s margins. Siberian iris, which I allow its own space because its seed swapping tendencies produce a myriad of different colored blossoms. There are some perennials whose rampancy is simple to control, like the creeping veronica, tiny china blue blossoms hovering over the garden in spring like a heavenly vapor, which I remove immediately after flowering. And the perennial geranium which controls itself, its tendrils hosting blossoms of pale to deep pink or purple or blue winding politely around existing plants without intruding upon them.

Certain herbs are notoriously invasive, and so the herb garden is not always simple to maintain. The tender herbs, such as basil, sage, sweet marjoram, culinary thyme, dill, simply can’t compete with the aggressive varieties of chives, oregano, creeping thymes, mint, lemon balm. Designing an herb garden that separates the rambunctious herbs from the frailer ones is the best way to cultivate all of them, none of which I would do without.

Conversely, invasive wildflowers are infrequent. Two exceptions are turtlehead, named for the shape of its pink or white blossom cresting stiff stems, and native aster, billowy bouquets in white, pale pink, lavender, and myriad blues. While I value these for their contributions to pollinators and the early fall garden, the turtlehead forming a wall in a few gardens, the asters creating clouds of the most heavenly hues, I must temper their encroachment on other flowers, weeding them in the spring when they emerge. Tall stalks of milkweed and the mauve tufts of the self-sowing Joe-Pye weed, shimmering sheaves of golden rod, bushels of black-eyed Susans and sunny daisies, cinquefoil, with its gentlest of yellows flowers, and veils of Queen Anne’s lace – these contribute so much to the garden in summer. And when they’re spent at the end of the season and have dispersed ample seeds, removing them is only an annual task.

Truth is I pretty much leave plants alone and let them have their way, dealing with the wayward ones when I must, rolling up my sleeves in early spring, mid-summer, or late fall to unceremoniously pull the offenders and discard them in the woods in order to preserve the coreopsis, the “silver mound”, the catmint, and restrain the loosestrifes, the bee balm, the phlox. Co-existence of diversity can be difficult to achieve. We learn this in politics and in the garden. But it’s possible.

Dayna McDermott