Seeking advice on this plant. Planted large drift of these euphorbias last Spring. Lost many of them, perhaps due to overwatering (they turned yellow and limp and were unrecoverable). Replanted euphorbias with less emitters and they did well through winter, flowering with beautiful chartreuse flowers. Now the problems are that there are few new shoots (tips of some shoots have turned dry and brown) and the leaves at base of mature stems are turning yellow. I love this plant and do not want to give up. Any tips on growing healthy euphorbias of this sub-species would be appreciated.