Yes. There's some myth that breeds like a TB cant get laminitis but thats crap apparently (my vet has seen one or two with it, although those weren't grass related but more stress / concussion). Natives are more prone to grass-caused laminitis because they tend to put on weight so easily which increases their risk.
All horses are at risk, you can look on the laminitis trust website to find further information on this I believe. As MagicMelon has said those that put on weight quickly are going to increase their risk of grass induced laminitis, but any horse can get it.
It is not just down to grass either. It can be caused by a number of different things such as an infections, worms, stress etc. Laminitis should be treated as a veterinary emergency and a vet called immediately oif it is suspected.
for the time being, my horse is going to live out at a place where there are no stables, until my stable is ready at another place. how would i keep my horse from becoming obese, would i just ride it off????