Daisy ... when do they take off and grow tall ?
I planted mine back in 2011 and have kept it about 4' tall.
I have always planned to grow it as a shrub. I had read that this is common practice in England.
I just decided that I wouldn't allow it to grow taller and have been shaping the growth below.
Last year, my magnolia got severely deer pruned, which is unusual, but I had a break in my deer fence in back and when I finally got the doe that was feasting on the garden up on the house pad blocked out of the back gardens, she decided to eat every deer resistant plant out in front. Now I am working at re-shaping the shrub this year because it looks kind of ratty, but I am not letting the plant grow taller.
For me, I just take a nip here and there as I walk by when I have pruners in my hands to direct the growth.