Alpine Troughs
Surprisingly, these collections of tough little plants survive the winter with out protection. The smaller troughs ( the ones I can lift) I group together in a south west facing corner of the house . The rest , larger and made of real stone are impossible to move , and so far have sailed through the Winter without damage to plants or container.
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There is a large selection of planters at most garden centres. If you want one that is suitable for alpine plants, you might consider ones made from a cement mix that approximates stone. They come in many sizes and shapes including round.