Very heavy weights in the range of 1-3 repetitions generally make people stronger but there isn't much hypertrophy. When you get from 3-5 repetitions, you're still in the mostly strength/some hypertrophy range. When you get out towards 6 repetitions out to even 30 repetitions, provided the sets are going to failure—you can't perform another repetition in good form, well, then you're stimulating hypertrophy.