There's not much choice when it comes to B. globosa flowers. Most are orange, the exceptions being HCM98017, which is very pale yellow, and 'Lemon Ball', with underwhelming yellow flowers. The lack of selectively bred cultivars is easily explained - the seedlings are delicate, being prone to both botrytis and root rot, and the plants can be slow to mature.
I've only had very modest success breeding new B. globosa plants, and have produced two yellow-flowered plants by crossing a generic orange female with HCM98017. One is a male called 'Kevin' and the one shown, a female full-sibling called 'Beryl'. The original seedling was raised in 2012, but that died after a couple of years. The plant I have is a cutting of a cutting, and now five or six years old. I'm pleased with 'Beryl', as females can be less showy and less floriferous. There are plenty of flowers and the balls are reasonably big. The scent is stronger too, and very like dandelion. A close-look at the flowers shows a lack of stamens, and these female flowers are described as pistillate, as opposed to the male staminate flowers with a non-functional, but still visible, pistil.
I'm raising seedlings of 'Beryl' backcrossed to HCM98017 (male) in order to produce a true lemon yellow, although I think the chances of realising that goal are rather slim. They have yet to flower and must survive another perilous winter before they can do so.
There is much more about this species, including a photo of 'Kevin', on the dedicated B. globosa and B. araucana page.
Royal Botanic Gardens Edinburgh kindly sent me seeds from some of their Buddlejas a few years ago. Always keen to grow new plants, I sowed the seeds and, after a couple of seasons, the results are starting to flower. The one shown was raised from the seed of C&H (Cox and Hutchison) 7039, a plant collected from South Sichuan (China) in 1995 and growing at their Benmore Botanic Garden in Argyllshire. Currently, the plant is catalogued as Buddleja macrostachya by the RBGE.
C&H 7039 is almost certainly self-fertile and, as far as I can tell, is coming more or less true from seed. The leaves of the seedlings are large and felted and the stems are covered in woolly hair; both are more in keeping with B. nivea and unlike B. macrostachya, which is significantly less hairy. However, species identification can be rather hit-and-miss without flowers to examine.
Now I can examine them, I can see the flowers are totally unlike B. macrostachya. They have a short funnel-shaped (infundibular) corolla tube compared to the long cylindrical corolla tube of B. macrostachya. Looking closely at the flowers of the commonly available plant of B. nivea type: yunnanensis for comparison, the similarity is evident, differing only in the length of the calyx. I'm convinced C&H 7039 is in fact Buddleja nivea, and most closely corresponding to the type: yunnanensis, which typically flowers about now - six weeks ahead of any B. macrostachya
When I saw an old Buddleja colvilei in the Birmingham Botanical Garden, I couldn't resist asking for cuttings. And the head gardener generouly allowed me to have some material. Now these cuttings are mature plants and they are flowering nicely this spring.
There is no information on the origins of this plant; there have been numerous B. colvilei introductions, starting in the 19th century, so it's anyone's guess where this came from. The form of this collection, which I'm calling 'BBG', is quite distinctive - the leaves are somewhat felted, and their overall appearance is very like the popular 'Kewensis' cultivar. The flowers are very different - they are large, up to 3cm in diameter ('Kewensis' has relatively small flowers for the species) and have a contrasting bright white throat. The main corolla colour is red-pink, not quite as dark as 'Kewensis' and the petals tend to be folded back.
I wonder whether there is some mileage in selectively breeding new ex situ examples of this species, developing improved hardiness and larger, more showy flowers. Such an endeavour would require patience - the seedlings don't flower for several years - and space, as the true form is only apparent in large, mature specimens.
A few years back, I was able to cross the pink form of B. colvilei with the 'Kewensis' cultivar. I'm not surprised there's so little selective breeding of these larger Buddleja species as the seedlings take several years to flower, and B. colvilei has proved one of the slowest. Finally, I've managed to make one of my seedlings flower.
The seedling's flowers are almost perfectly intermediate between the parents, which can be compared here. 'Kewensis' has a smaller individual flowers, but those of the seedling are larger and have a white throat like the pale pink parent. The corolla though is a deeper and more intense pink, although not as dark as 'Kewensis', which can be almost maroon in colour.
I grew the seedlings for the sake of curiosity. Although not massively different from the B. colvilei collections and cultivars already available, this one is nice enough to keep. Another year in a pot and it should be large enough to plant outside. I'll have to also repot and heavily feed its siblings to encourage their flowering next spring, and maybe I'll get something truly unique.
I've had Buddleja collection KR4881 growing in my garden for a few years now, and it's proved shy to flower - and when it does, the effect is underwhelming. For a plant from Tibet, it's remarkably intolerant of frost, losing most of its flower-buds each year unless the spring is particularly mild. Despite this, the plant healthy and has grown into a small straggly tree with a rather congested habit (the grey, toothed leaves are densely packed with exceptionally short-internodes).
The inflorescences are formed on the lateral branches formed the previous year; these are clusters of flowers in the form of glomerules or congested cymes. Other than being off-white and appearing a little earlier in the season, they are essentially the same as the more common form of B. alternifolia. It does differ in keeping much of its foliage over a typical English winter, whereas B. alternifolia is fully deciduous.
Although KR4881 was originally identified as B. x wardii, I don't believe there is any evidence for it being from the hybridisation of B. crispa and B. alternifolia. It corresponds exactly to Buddleja tsetangensis, sunk as a synonym of B. alternifolia by Leeuwenberg (1979). A specimen of Buddleja tsetangensis was collected in the Tsang-Po valley of Tibet and sent to Edinburgh in 1924 by the plant hunter F. Kingdon Ward. Described by Kingdon Ward as a small gnarled tree, locally common, and flowering in April, the flowers cream with an orange throat.
KR4881 does merit recognition as something distinct, and personally I might be tempted to consider it as a variety or subspecies - B. alternifolia var. tsetangensis - rather than a species in its own right or as merely a local Tibetan form of B. alternifolia.
A while back I bought some seeds of Buddleja salviifolia from a reputable source in South Africa. They've taken a while to mature, and I now have four mature and healthy plants. The two kept outside haven't flowered and I suspect these seedlings are a little less hardy than the common blue cultivar sold in most nurseries. Maybe they will become more robust as they get older - I've certainly found the white form, which my seedlings resemble more than the blue form, to become significantly hardier with age.
Last year, a seedling with lilac flowers bloomed in my greenhouse, which has flowered again this year with a consistent colour. A different seedling has just opened a delicate violet in colour, fading to almost cream as the flowers age. B. salviifolia is very variable species, and various shades of lilac and violet are common in Africa, although these colours are rare in cultivation.
Many species are represented in collections and in the horticultural trade by just one or two atypical clones. Conversely, I've become more interested observing several different examples of a single species and maintaining a wider ex situ genepool. I don't think these Buddleja salviifolia with their averagely coloured flowers will have a greater appeal than the already available plants, but they are something I couldn't have obtained any other way than by growing from seed.
Another year begins in The Buddleja Garden. There's never much happening in the bleak midwinter, so I thought I would mention a project with which I've been involved. Trees and Shrubs Online (TSO), managed by the International Dendrology Society and sponsored by the John Spedan Lewis Foundation, is an online resource cataloguing and describing the woody plants grown in temperate gardens, parks, arboretums and so forth. It's a monumental undertaking, and has much to live up to as the online successor to the revered Bean's Tree and Shrubs.
I was rather honoured to be asked to contribute the Buddleja pages. The job is almost complete and the Buddleja pages can now be found via the Buddleja Genus page. There's still a little way to go, for example I've yet to properly systematise and describe the new dwarf hybrids.
Please do have a look, both at the Buddleja pages and the rest of the site. When complete, I don't think there will a single reference work on the internet, or in print for that matter, that will come close to Trees and Shrubs Online, which aims to be up-to-date, meticulous and comprehensive.
The antique illustration, just for decoration, is one of my favourites: Buddleja x intermedia, a hybrid of B. lindleyana and B. japonica, raised in France many years ago.