There's a 6ft x 30ft area in my yard where the grass always withers every summer. I figure the soil's really shallow so we decided to plant a tree there. I dug a hole and hit rock 3 inches down. I tried another hole, and another, and another, and still rock. I used a probe and figured this area is just full of rocks, or maybe just 1 huge slab of limestone.
I don't know how thick this rock is. Any suggestions how I can plant a tree there? (BTW, I don't have any dynamite).

We found one like that at my moms house and ended up scrapin all the dirt off of it about 5 foot round and tried bustin through it with sledges for about 2 hrs...we put the dirt back

rent a jackhammer

if its a solid slab, look to renting a mini digger with ditching bucket to strip the soil and then a breaker for the same machine, then use the digger to dig all the loose rock out

bring in some good sandy loam and plant some grass

You might be digging on top of an old septic system

No, this place was newly developed about 15yrs ago and it was all hills. I'll have to price the jackhammer or the digger and see if the cost is worth planting 1 tree there.

Check with your neighbors and see what they have. Usually rock runs in a layers throughout an area. Depending on different contours, it could be 3" deep at your place but 30" deep at theirs. Depending on the depth, trying to bust through an area as well defined as what you stated might be a bigger issue than what you want to get into.

Bring in a layer of good soil (12+ inches)and make a drought tolerant bed out of that area and plant a few trees around it. It makes a nice look in a yard without the headache of having to water. The root system of drought tolerant plants will sometimes break through the rock and survive for years.

Texas sage, yuccas, salvia greggi, lantana, etc. are some good drought tolerant plants that are perennial.