[header] How to grow a pencil tree (euphorbia tirucalli ) [title] Check the roots. [step] When buying any potted plant from a nursery or garden center, gently life the plant out of the container and look at the roots. The plant should have these characteristics : [substeps] A firm but not compacted root ball. 
White roots that do not show any signs of rot. A dense cluster of roots that hold the soil.