Cora, I have found that here in FL my brugs do better in pots. If you have nematodes in your soil (and most of us do) the brugs attract them like crazy. I had one that flourished for about 3 years and then went into a decline and died despite all my best TLC. When we pulled it out, sure enough the roots were all knotted up with nematodes.
So, I'd just caution you to first solarize (sun bake) the soil area where you are going to plant your brugs, and then amend the area heavily with compost. You will have to top dress generously with compost each year after that as well, because the organic material breaks down so fast in our hot, humid climate. The nematodes like the loose, sandy soil, but are deterred somewhat by soil that has a high percent of organic amendments.
Or invest in some big pots! I just prune my big ones back about halfway in winter so that I don't have to re-pot them too often.