We are thoroughly alarmed at the disappearance of many old and beautiful selections of Regals/Martha Washington Pelargoniums from nurseries on the West Coast. Fortunately The International Regal Preservation Project www.geraniumsonline.com/regalproject1.htm in San Diego, CA is working to save representative samples of as many Regals as they can find. Please contact them if you have Regals you want identified (try sending photos first, then plants if required).
The parentage of Regals (Pelargonium x domesticum) is rather murky but most plants have coarse sawtooth edged dark green leaves, although there are a few variegated leafed plants. As you probably know, Regals can grow as big as a bus, particularly in California. But you don’t have to be dominated by your plant. Judicious pruning can turn a monster into a well behaved and beautiful container plant. The flowers are large and dramatic and come in many colors with the exception of yellow and blue and are decorated with blotches, stripes and veins in contrasting colors. Plants usually stop flowering when the nighttime temperatures rise, but flowering can be greatly extended by pruning and fertilizing.
Where possible we have used The Pelargonium International Register and Checklist of Pelargonium Cultivars, published by the British and European Geranium Society, 2008 as a standardized guide to the names and color descriptions of the flowers. No source is listed where the provenance is unknown. Finding correct labels for these plants produces exquisite frustration. Comunicate with The Regal Preservation Project or Geraniaceae if your similar plant has a different name.