It is a pretty slow palm, as are all the Sabals, but faster where it is constantly warm and humid (not like here in southern California where it is painfully slow). It takes up a lot of room, so remember that when planting it. Otherwise, it is not a picky palm and will grow in just about any situation.

Its not the slowest Sabal but lzrddr says it does need good summer heat and lots of sun to grow well. I have tried them in the UK and they are a complete waste of time.

I agree, all sabals are slow, especially at seedling age. But if there's enough heat, it will grow at a moderate rate. Still, even in tropical climates it will probably take most sabals an entire decade at LEAST from seedling stage to form a trunk. Try to get as mature of a plant as possible and you might manage to get some height on it. Im sure the more tropical species of sabal are a little faster growing than the more cold tolerant ones (But I must admit that with all the heat here this summer, my sabal minor has been growing like crazy!)
Good luck!
-Alex

Yep, even here in the FL panhandle it takes awhile for them to form a trunk.

Only thing I don't like about these palms is that they grow very big and wide. You need slot of space. That puts me off.