Fourteen summers of battling the weeds in our lawn have left me with a weird, foliage-driven sense of the calendar.

If I’m twisting loose chickweed with a weeding fork, it could be February but it shouldn’t be later than April, lest I waste my efforts on plants that have already gone to seed. Pungent deadnettles come about a month later. followed by crabgrass.

And from late spring on, I can expect to see Ailanthus altissima saplings invade the front yard. “Tree of Heaven,” my ass: This invasive, quasi-viral plant grows like a weed, literally stinks, and spreads with zombie-like persistence.

Clawing out one of our worst imports from Asia requires advanced stubbornness. Plucking a shoot out of the lawn is easy but leaves a densely-coiled root that will send more growths aboveground within days.

You have to shove a trowel underneath it, elevate a clump of lawn, then feel through the dirt for that root mass and then tug it loose. Done right, you’re left with a long stretch of subterranean subversive that can no longer make a nuisance of itself.

I want to think I’ve seen results this summer, in the form of patches of lawn that haven’t sprouted new ailanthus shoots in weeks (but do show the collateral damage of bare spots that I’ll have to re-seed in the fall). It may seem like an endless task, but it can’t be as futile as trying to evict our single worst import from across the Pacific, the tiger mosquito. Right?