These are hybrids of species other than B. davidii that I have some experience of growing. Just like the species from which they are derived some are fully hardy and some benefit from winter protection. Many are from crosses of species that wouldn't normally come into contact as the parents are from different continents: South America; Asia; Africa

Blue Chip

Complex hybrid

Okay, so this one does have some B. davidii in its DNA. Bred by Denny Werner of North Carolina University, it has B. davidii, B. globosa (via the B.x weyeriana hybrid Honeycomb) and B. lindleyana in its complex ancestry. The good things about Lo and Behold Blue Chip: it has nice dark green to grey foliage that is shaped more like B. lindleyana; it stays low; sets almost no fertile seed; very hardy and ever-green; has very densely packed PURPLE flowers. And that's the only problem - the flower colour is nowhere near blue although still a good intense shade.

It is the first of a series of 'Lo and Behold' mini-Buddlejas which includes Lilac Chip, Purple Haze and Ice Chip.

There is a separate page on the Lo and Behold Hybrids.

Morning Mist

B.loricata X B.crispa

Bred by Peter Moore at Longstock Park. Very attractive grey/silver foliage, scented white flowers and usually stays less than a metre tall. Just about hardy in England but it struggled in the recent harsh winter. Also listed as Silver Anniversary.

Pride of Longstock

B.lindleyana X B.crispa

Yet another great plant from Peter Moore at Longstock Park, also called Longstock Pride. The same cross as the rare Pride of Hever hybrid which it closely resembles. The leaves are more like B. lindleyana but slightly serated. The typical Buddleja flowers are bright purple in open panicles and have retained some of the fine B. crispa scent. It dies back in winter but bursts into life in late March. It is supposed to stay small but mine is well over two metres in only it's second year.

Salmon Spheres

B. globosa X B.crispa

An unusual cross to try. This strong growing shrub has leaves that are shaped more like B. globosa but white felted like B.crispa. The flowers are globose and pink fading to yellow, clour is rather dependent on the temperature. My book says it flowers late spring with no repeat flush. Plants don't read books so mine flowers sporadically from April through to October, probably because it fails to set seed here. I have been told it is fertile in warmer climates. Hardiness is somewhat suspect but I have found it quite hardy where reasonably sheltered, but it could benefit from being brought into an unheated greenhouse for the winter.

Winter Sun

B.nappii X B.officinalis

Another unusual cross. Globose pinky-orange dusky flowers. Hardiness is suspect so it needs a very sheltered spot or over-wintering in a cold greenhouse. It is a very vigorous shrub with brown felted stems and leaf-undersides, the leaves are large and soft, features inherited from both parents. Mine has survived outside in the mild winter of 2013/14 and flowered copiously in April, although it would be earlier under cover.

A few more hybrids you may encounter:

There is a page on the Flutterby and Hinebud Hybrids.

Buddleja Argus White syn. Inspired White
Buddleja Argus Velvet syn. Inspired Violet
Both hybrids of B.davidii and B.lindleyana, raised in Belgium: Buddleja Argus

The purple Buddleja "Argus Velvet" is also known as "Inpired Violet".

Orange Sceptre: B. stachyoides B. tubiflora
Winter Waterfall: (B. asiatica B. crispa) B. asiatica
See: Lindstrom, J.T., Dunn, B.L. and Renfro, S.E. (2009). Buddleja 'Orange Sceptre' and 'Winter Waterfall'. J. Environ. Hort. 27:188-189

Wattlebird: B. madagascariensis B. asiatica
Raised by R.J. Cherry in Australia in 1993.