KP Gardens

The Dreaded Herb Robert, or the Curse of Stinky Bob — Beware Ye Gardeners!


On most summer days, you’ll find me toiling away in the garden, crawling around on all fours or standing at a 90-degree angle, hands on my hips, staring into the green and brown abyss like a mad woman on the hunt for one of my archrivals, the dreaded Herb Robert.

To the unsuspecting novice, Herb Robert (Geranium robertianum), also called Robert’s geranium, looks to be a splendid native wildflower. Preferring to grow on woodland edges, the delicate pink flowers adorn the long fuzzy red stems against a backdrop of elegant lacy foliage. So effortlessly does it form large drifts among the ferns and salal that it almost seems wrong to assume it’s a stranger from a far-off land. But that’s exactly what it wants you to believe.

Herb Robert is among the nastier little weeds we must contend with here in the PNW. Along with most of our noxious intruders, it was brought here as either a medicinal herb or someone’s favored cottage ornamental, and from there it made itself at home, choking out less competitive native species. To eradicate it would be a resounding victory for the region. But its greater ecological impact is beside the point. Where it really gets on my nerves is where I don’t want it — in my dang gardens!

But compared to other weeds, a young, tender Herb Robert is my preferred adversary. It’s easy to identify and easier to pull than most invasive species, which tend to anchor down with tap roots that might as well be a mile long. And unlike hairy bittercress or creeping oxalis, the seed pods don’t explode upon the slightest graze and shoot me in the eye. But that’s where the redeeming qualities of Herb Robert end for me.

The moment Herb Robert begins to sprout in spring it’s a race against the clock to locate and remove as much of the population as possible before it goes to seed. Of course, it’s a crucial time for controlling a plethora of our most persistent weeds, but there are some things unique to Herb Robert that make a mature plant especially dreadful.

As the arrival of longer, warmer days triggers most plants to bounce into reproductive action, Herb Robert is no exception, and like a teenage boy with unsupervised access to Old Spice, Herb Robert develops a most obnoxious stench.

If you’ve never had a whiff of this particular aroma, imagine basting Brussels sprouts in paint thinner. It’s about like that. It’s a sneaky sort of stink too because Herb Robert doesn’t gas you until it’s pulled. I’m assuming this is some sort of defense mechanism against herbivores that seems to have been duly noted by our local fauna since the plant has spread so efficiently.

As if the smell wasn’t bad enough, the early sprouts that were so small and easy to shimmy out of the soil turn into spindly behemoths that become intertwined with every neighboring ground cover, shrub, and ornamental grass, rarely ever in a convenient location to yank out. Identifying the origin point of one of the gangly stems is a mystery one does not care to solve in the middle of an oppressively hot day. And despite my best efforts to glare them into submission, I often find the best I can do is decapitate the exposed peduncles to slow down Stinky Bob’s pace until the fall frost finishes the job.

I’ve tried not to regard invasive plants as anything other than what they are — the enemy. There’s a phase all new gardeners go through where we decide to learn about the weeds in our gardens to maybe appreciate their purpose beyond being a menacing fart carpet on our forest floors. A quick Google search will come up with a lengthy list of the traditional uses of Herb Robert. One is, quite fittingly, a treatment for diarrhea. A study published on the National Library of Medicine’s website from May 2023 examined Herb Robert’s antibacterial properties that showed promising results in the plant’s ability to treat “hard-to-heal wounds.” Physical, not emotional, unfortunately.

Despite these attempts to endear Herb Robert to me, none of it changes the fact that it just doesn’t belong here. Until further studies prove its potential as a medicinal cash crop, I can’t afford to see it as more than just a stinky weed. The hunt must go on.