Pelargonium
Surely among the most easily grown and showy of plants for house, greenhouse or summer bedding are the so-called bedding geraniums - species and cultivars of Pelargonium.
RHS trials
Pelargoniums have featured regularly in the RHS trials programme. Since 1992, trials have led to the recommendation of the Award of Garden Merit for the most outstanding entries.
Current work at Wisley on Pelargonium
Taxonomy of Pelargonium cultivars
Further reading
Miller, D. 1997. RHS Trials. Scented-leaved pelargoniums. The Garden (RHS) 122(3): 160-164.
Miller, D. 1996. Pelargonium. A gardener's guide to the species and cultivars and hybrids. London: B. T. Batsford.