A practical guide for homeowners who have noticed something leafy behaving with what can only be described as intent.

Every year, without fail, I receive correspondence from readers who describe a plant in their garden that has developed what they variously call ‘an attitude,’ ‘a presence,’ or, in one memorable letter from a woman in Keene, ‘a way of looking at the dog that I don’t care for.’ In most cases, these readers have already spent some time Googling the variety, concluding it is probably a viburnum or an overgrown rosemary, and deciding to simply keep an eye on it. They are, in most cases, wrong. They are, in most cases, keeping an eye on a Ya-Te-Veo. I am publishing this list because the volume of correspondence has increased this spring, and because at least two of those letters were postmarked from my own street.

Sign One: It Has Grown Seventeen Inches Since You Last Looked At It Forty-Five Minutes Ago

This is, I appreciate, a difficult thing to verify once you are already inside with the door locked. Nevertheless, think carefully. You glanced at it this morning when you put the recycling out. It was approximately level with the garden wall. You glanced at it again when you went to collect the post. It was above the garden wall. You are now reading this article. The wall, if you care to check, is no longer fully visible. Ordinary shrubs — viburnums, rosemaries, photinias, even an enthusiastic buddleia — do not add seventeen inches in forty-five minutes. They do not add seventeen inches in a month. Rapid vertical gain in the absence of a growth cycle, particularly when accompanied by any of the following five signs, should be treated as confirmation rather than a curiosity.

Community Notice

We initially thought it was an ornamental grass that had got a bit out of hand over winter. Then it ate the birdbath. I want to be precise about that word — ate.

— Rhonda Pfeiffer, Brattleboro, submitted account (28 witnesses on file)

Signs Two Through Six: A Consolidated Assessment

Sign Two: It leans toward foot traffic. Not toward the sun — toward movement. Stand still in your garden and watch whether the plant reorients. Ordinary phototropism is slow and involves the whole stem. What you are looking for is a decisive, considered lean, the kind that tracks. Sign Three: The garden cat is gone. Not your cat, necessarily — though if your cat is also gone, please proceed to Sign Four immediately. The garden cat. The one that belonged to no one and slept on your fence and occasionally left things on the step. Its absence is relevant. Sign Four: The soil around the base has been disturbed in a pattern that is not consistent with root spread, frost heave, or any animal you are prepared to name. Sign Five: You feel, when you look directly at it, that looking directly at it was a decision it was waiting for you to make. This is not a diagnosable sensation. I am aware of that. I am including it because it is consistent across thirty-one separate accounts I have collected over the past eight years, including three from individuals who described themselves as deeply sceptical, and who are now deeply something else. Sign Six: It has tendrils. It did not have tendrils last week. The tendrils are not reaching toward the fence.

The difficulty with identification at the residential scale is that most people’s frame of reference for ‘dangerous plant’ is ‘nettle.’ They’re not wrong about nettles. They’re simply operating in an entirely different category of problem.

— Dr. Constance Farrell, Botanical Anomalies Unit, University of Vermont (emeritus)

I want to close with something practical, because I have found that practical information is what people actually retain when they are frightened, and if you have read this far and recognised more than two of the above signs, you are probably frightened, which is the correct response. Do not cut it back. Do not compost anything that has fallen from it. Do not water it, even if the summer is very dry and some part of you feels that not watering a plant in a drought is unkind — that instinct is, I suspect, not entirely your own. Call someone who knows what they are doing. I keep a list. It is not public, but it is maintained, and if you write to me at the WTC address with your situation described clearly and your county in the subject line, I will tell you who to contact. I have been keeping this list for eleven years. It is, at this point, the most useful thing I own, and I own the instrument in the car park and the notes in the brown envelope, so that is not a statement I make lightly.