ROFL....ours did that!!!
We could even do "baby-levitation". If we were holding him over the grass, and lowered him slowly, his legs would raise at a perfect 90 degree angle, so his feet/legs wouldn't touch the stuff...Then as we raised him up his legs would go back down. It was as if there were magnets involved. He wouldn't actually get upset, unless we set him down in it, so it wasn't like we were being cruel.
But yes, HATED grass. Fine with woodchips. LOVED gravel. Wasn't fond of dirt/sand...and would throw a FIT if he was "dirty". Gawd...the number of road trips we took with emerald green grass & playgrounds at reststops and all he REALLY wanted was to play in the gravel at the curb. Head Thwack.
So we catered to it, without it being obvious. We're outdoorsy, we're going to be outdoors. We're not going to change that...and quite frankly, he could walk through his quota of parking lots & carpets in daily activities...I wasn't going to spend MORE time there then we already were. So by catering to it I mean:
The repeated safe "fly-by" exposure: I carried my son a lot. I would cut over grass/mud/sand. If he made a fuss, I'd laugh and say "Silly! I'm not going to put you down. You don't like "X" right now, but I do. Good thing people like different things!!! What if you had to carry me???"
The barrier method: Shoes, and socks, and pants and blankets. Made a big deal about how the things he hated couldn't touch him through them. I'd go barefoot, or loll in the grass and he could have his shoes and picnic blanket. Fine with me. We were out of the house.
The cest le vie method: Fine, we're at greenlake. If you will only stay on the path, okay. I'm not even going to mention it.
The what-happens-next method: AKA: 1) The grass touches you, it's kind of tickly...but that's all. As soon as it's not touching you...look! It's not touching you! Touching, not touching, touching, not touching! 2)You get dirty, we wash it off when we get home. We know it's fun to be clean, it's also fun to get dirty. What MOST fun is getting dirty then washing it off! Poof! Like magic.
((I swear, not only the tomboy who had a son who was afraid of getting dirty...but NOW we did our job too well...if a mudpuddle exists...he'll not only find it, he'll add more water and dirt to it because it won't coat him evenly otherwise. Pendulum left, pendulum right. Head thwack!))
The word shapes action method: Whenever we talked about it, in his hearing or not, we used the phrase "He doesn't like grass right now", or "yet" and shrugged. Constant verbal conditioning that not liking grass is something that will change, instead of saying he's afraid of grass, or hates grass, or doesn't like grass...it was always "right now", "yet", etc.
It only took a couple of weeks for the trust to build that I wasn't going to set him down or force him somewhere green (heaven forbid) or dirty. It took a couple of years for the phobia to actually wear off. The final straw that broke the camels back, was when he got more interested in playing with other kids then avoiding grass. Didn't happen until he was three, although he'd played with tons of kids before that. Just one day, there he was out playing tag in the grass.
And yes...3 years later...I'm still scrubbing grass stains out of knees with "But MUM! I LIKE green knees."
So that's our story. Long. But not super traumatic.