Adenium Arizona (obesum X swazicum Hybrids)

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This is by far the commonest interspecific cross in adeniums. The A. swazicum parent contributes solid flower color, cold tolerance, and rot resistance. The A. obesum parent contributes mainly strong, erect growth form, and often good round flower shape. Additionally, hybrids between these two species tend to have large caudexes (actually huge roots), long blooming seasons, and particularly intense flower colors. In summary, these hybrids are very often better than both parents; there are many named cultivars in the trade.

[About 1990 I gave the grex name Arizona to all hybrids between Adenium obesum and A. swazicum. Since then the International Code of Nomenclature for Cultivated Plants restricted the term "grex" to orchids only. So technically this hybrid swarm should now be called group Arizona. The group is identified by solid-colored flowers with darker throats on vigorous plants. The plants also usually have greatly swollen roots and the flowers have rather short anther appendages. Second-generation and further hybrids may have pale throats.]

This page: 'Crimson Star' is an early and well-known adenium hybrid. The cross was made in 1985 by Mark Dimmitt. The seed parent is A. obesum 'Red Everbloomer'. It is a mediocre plant by today's standards, but at the time was a rare everblooming clone, and additionally it has sturdy, upright stems and greatly swollen stems and roots. It contributes these traits plus intense flower color to its offspring. The pollen parent, A. swazicum 'Boyce Thompson', is a long-blooming clone with deep purple flowers.

Photos by Mark Dimmitt unless otherwise noted

'Crimson Star' (bottom) flanked by flowers of its parents 'Boyce Thompson' and 'Red Everbloomer'

A four-year-old cutting of 'Crimson Star'.

'Crimson Star' photographed with a digital camera. The color is truer than the image at far left.

Adenium 'Crimson Star'
A14-year-old cutting of 'Crimson Star'


The same seed pod that produced 'Crimson Star' in 1985 also yielded three other good red hybrids. It must have been beginner's luck. In 1995 the cross was remade and about 100 seedlings grown out. Not one was worth keeping.

'Little Ruby' flowers are slightly smaller than those of 'Crimson Star' and has green leaves. The plants are equally vigorous and bloom year-round.

A cutting-grown 'Little Ruby', ca. 5 years old.

'Volcanic Sunset' is paler than 'Crimson Star' and the plant is more compact. The color of this image is off; the next picture of the whole plant is truer.

The original plant of 'Volcanic Sunset' at about 15 years of age.

'Red Ribbons' has very large flowers; the petals of older flowers droop like ribbons. The plant is more swazicum-like with weak stems and not much succulence. It blooms heavily most of the year.



(click on thumbnail for full size picture)