The genus Clivia Lindl. (Amaryllidaceae) contains six described species: C. miniata, C. caulescens, C. gardenii, C. robusta, C. nobilis, and C. mirabilis (Zonneveld, 2004). All Clivia originate from Southern Africa. Of the six species, Clivia miniata is the most popular in cultivation because of its large, upright, attractive flowers borne in an umbel. The other five species have smaller pendent flowers. Clivia make excellent house plants because of their attractive foliage, flowers, and tolerance of dry and low light conditions. They are shade-tolerant landscape plants, which are hardy in United States Department of Agriculture Zones 9 and 10 (Koopowitz, 2002).
Longwood Gardens in Kennett Square, PA, began breeding Clivia in 1976. The initial goal of the breeding program was to produce a superior yellow-flowered plant for use in the Longwood conservatories. When the breeding program started, yellow-flowered Clivias were rare in cultivation, and the flowers needed improvement to increase tepal size and presentation of the flowers. The first breeding cross was made between a yellow-flowered plant of unknown origin and a large orange-flowered plant from Gordon McNeil of South Africa. By crossing these two plants, it was hoped that a plant with superior, large yellow flowers would eventually result. All flowers of the F1 generation were orange. The F2 generation yielded a mix of orange and yellow flowers. Other yellow-flowered plants were acquired from Sir John Thouron of Pennsylvania, Dick Ryan of South Africa, and Glasshouse Works, Ohio, and added to the program. In 1984, a seedling from a 1980 cross bloomed with keeled tepals. This was unexpected, and led to new breeding goals of multipetaled flowers and flowers with consistent prominent keeling. The production of a multipetal flower from keeled tepals proved to be elusive, but consistently keeled tepals were within reach.
The first introduction from the breeding program was released 35 years after the program’s inception. The time needed to reach the initial breeding objectives was due to several factors. First, seeds can take 8–10 months to reach maturity after pollination (Merwe et al., 2005). Second, it can take a seedling a minimum of 3–4 years to bloom for the first time (Duncan, 2008). Finally, the only readily available means of clonal propagation of Civia has been vegetative division, which is a slow process. Because of the time and effort that goes into Civia breeding, superior Clivia plants are coveted by collectors who will pay top dollar for a superior plant. At their release, Longwood Clivia cultivars sold for $900 apiece.
The breeding goal of superior yellow flowers was met in the release of C. miniata ‘Longwood Debutante’ in 2010 (Fig. 1). ‘Longwood Debutante’ produces slightly fragrant, rich yellow flowers with overlapping tepals, on an umbel above dark green foliage. Clivia miniata ‘Longwood Fireworks’ is the second yellow-flowered plant that was released in 2011 (Fig. 1). ‘Longwood Fireworks’ produces large, paler yellow flowers with reflexed tepals and protruding stamens, which are held on a spherical umbel above the foliage. Clivia miniata ‘Longwood Sunrise’ is an orange-flowered C. miniata with consistently keeled tepals that was released in 2014 (Fig. 1).
Cape Clivia Club 2008 Clivia colour chart II. Cape Clivia Club, Kenilworth, South Africa
Duncan, G. 2008 Propagation, p. 147–155. In: G. Duncan (ed.). Grow Clivias. 2nd ed. Mills Litho, Maitland, Cape Town, South Africa
Koopowitz, H. 2002 Cultivating and growing Clivia, p. 89–122. In: H. Koopowitz (ed.). Clivias. 1st ed. Timberpress, Portland, OR
Merwe, L., Robbertse, H. & de Kock, B. 2005 Practical hints about sexual propagation and nourishment of clivia seedlings, p. 19–25. In: L. Merwe, H. Robbertse, and B. de Kock (eds.). Cultivation of Clivia. 2nd ed. South Africa Clivia Society, Pretoria, South Africa
Royal Horticultural Society 1995 RHS colour chart. 3rd ed. Royal Horticultural Society, London, United Kingdom
Smith, K. 2011 Longwood Debutante. Clivia Registry. 7 Apr. 2015. <http://www.cliviaregister.com/>
Smith, K. 2012 Longwood Fireworks. Clivia Registry. 7 Apr. 2015. <http://www.cliviaregister.com/>