|C. rigidus produces stiff growth with large, deep green leaves and abundant small, dark red flower spikes. This cultivar is unlikely to reach more than seven or eight feet in height at maturity.This evergreen shrub or small tree gets its species name citrinus from the lemony smelling oil glands present in the olive green, lance-shaped leaves. Spring to summer flowers are terminal, axillary, and crimson colored. Plant in neutral to acid, moderately fertile soil in full sun. This plant is tough and makes and excellent hedge. Regular prunning is not necessary. If you do prune, immediately after flowering is best.