A wallmower is often associated with people who are obtuse, socially inept, or cruel - tho sometimes they are acting in this way to eliminate party weeds.
"Look at this idiot, just sitting there and being all quiet, what's his deal?!" "Hey, stop, you're being a wallmower!"
"I dont think that's a wall flower, I think it's a party weed." "Hold on, I'll go mow him, but back me up if he Hulks out."