Sedum in Winter Condition

Sedum in winter condition.  These are planted in cement blocks and are completely covered by the plant

A cold front moved in today but didn't effect the high temps predicted.  When the wind died down I came out to enjoy the garden.  The sedum I have is a very nice winter plant to have here in Oklahoma.  This plant is from my great grandmother's garden.  She would plant several varieties in upturned cement or terracotta blocks and line her iris bed with them.  Among other plants in these folksy containers were Oxalis,  Blue-eyed Grass, Portulaca , & Grape Hyacinths.  Last year I took cuttings, (with some root still attached), in the spring rather than in the summer so they could take advantage of the wet part of the year to establish themselves.  The flowers are beautiful yellow at the end of tall stalks set up in the spring.  Skippers and other insects love them and my Korean sister-in-law told me they use it as salad food.  In real cold weather the ends of this plant turn reddish purple or just purple.  Other plants do the same in the garden and I've read articles where it is believed that the reddish tint (anthocyanin) is a way of protecting the plant from damaging sunlight and drought during the winter.