Mammillaria prolifera var. texana

Mammillaria prolifera var. texana seed was collected west of Comstock, TX at one of the Pecos Bridges. These should be zone 6b maybe colder depending on microclimate. They have done okay tucked in a crevice in our garden like epithelantha micromeris. So if you can find the right microclimate they will be more cold hardy. Just depends on your garden. I am trying several in holes ive drilled in rocks in the garden. If you have been to our garden you will understand.