Echinocereus viereckii subsp. viereckii

I have one Echinocereus viereckii subspecies viereckii in a 6-inch pot available. As seen in the picture, there is one stem that is turning yellow and dying off but is being covered up by the other, more vigorous stems. I find this species and all its subspecies grow better for me when planted in the ground than when I grow them in pots but others I talk to have no trouble growing them in pots. If you love Echinocereus, this is a must have.