I would probably take Snowbanks inside for the winter. I can't keep one alive long enough to have to worry about it though, lol. As to your soil if its really sandy you can ammend it with lots of compost and organic matter and that should help. They need lots of water if planted in full sun. If you can provide them with some late afternoon shade at least and maybe put a soaker hose around them and mulch they should be ok. They need lots of fertilizer to grow and bloom the same year. Once they get bigger and form a Y in the branch start pouring the bloom booster to them and they will bloom. Some of the others with sandy soil are using milorganite with great success. I got a bag myself and am going to try it this year. Good luck!

My Snowbank's haven't bloomed yet either but that and Miner's Claim are the only variegated brugs that I have a problem with. The foliage grows but no flowers. I wouldn't have left Snowbank inground unless I was in a frost free climate. The others would probably do well inground year round. You could even take them out of the clay pots, put them in nursery pots and sink them so you could dig them up in the fall if you were concerned that they wouldn't make it. I think brugs do better inground and are so much easier to care for. Even if you are planning on keeping them in pots I'd take them out of the clay and put them in plastic. They dry out even faster in clay and the small roots will become stuck to the inside of the pot if it's not glazed. You can always put the plastic pot in a decorative container. Snowbank might still be alive. I wouldn't completely give up on it until maybe mid May in your zone. It might yet send up new growth from under the soil. Good luck.

My preference is to plant in the ground and let them over-winter outside but ONLY if they will be hardy to my zone. What is actually best for the plants...sink pots in the ground and dig up for winter or plant inground and leave for winter? Either is doable for me--I just don't know which is best. Also--After wintering in pots in my garage, the Santa Rosa is probably 3'+ and the Cypress Garden is a little shorter. How much bigger will they need to get before starting to form a "Y"?

Forming a Y isn't size dependant. I can't tell you what is best. They will die down during the winter but should return in the spring in your zone. You can always take cuttings and root them over the winter in case they don't make it. Fertilize your brugs weekly during the growing season and give them ample water and you should get blooms.