You can encounter wake turbulence in any part of the sky, from any preceding aircraft, though at higher altitudes, and your flying faster, the effect will be more manageable. I'm very pleased to hit my own wake turbulence following a well flown loop.
Encountering wake from a "heavy" ahead of you should always be considered, and avoided, but if you're flying at Va or just slower than, and a thousand feet or so up, you'll have a chance to limit it to a really rough ride, rather than being slammed out of control into the ground.