The unusual and exotic pencil cactus plant is very easy to grow as long as it receives sufficient light.
Euphorbia tirucalli is a mass of pencil thick, shiny green stems which jut from the thicker main stems at every conceivable angle. Tiny leaves will sometimes appear along the stems.
Euphorbia tirucalli performs well in poor, dry soil and can grow into a tree 30 feet tall in just a few years.
In Zimbabwe it is known as rubber hedge and it is used for thick, zero-maintenance hedges.
The most important thing is to place it in bright sun. This plant stretches toward the sun and lack of light will cause it to droop and loose its upright growth habit.
Plant it in fast draining soil and don't provide supplemental water except during long periods of drought.
Feed Euphorbia tirucalli once a month, but only when the soil is moist.
Pencil cactus propagation is easy. Take cuttings of any size and let them dry for a few days before placing them into fast draining soil. Keep them shaded and barely moist until you see new growth. Shift the new plants gradually into higher light.
If you suddenly notice bees swarming around it, it is probably blooming. The flowers are inconspicuous and it is unlikely you would ever notice them otherwise.