SPECIES BUDDLEJA

These are the Buddleja (Buddleia) species that I have some experience of growing, some are fully hardy and some benefit from a little winter protection. They are from China and the Himalayas, Africa and South America. All African and Asian Buddlejas are hermaphrodite (male and female in the same flower), but many Buddlejas from the Americas are dioecious (separate male and female plants). There is some confusion because the flowers appear to have both male (anthers) and female (pistil) parts but one or the other is non-functional. This is called cryptic dioecy and species that display this are described as being cryptically dioecious; in older texts it can be described as micro-dioecious.

I have found many Buddleja species currently being sold are misidentified and therefore mislabelled. Wherever possible, I have attempted to confirm, correct or comment on the labelling using the monograph of Leeuwenberg (1979).

See also:
A Comprehensive and Organised List of Buddleja Species
(with Wikipedia links)


Buddleja albiflora

Superficially, a species very like B. davidii, although it is not necessarily closely related. Despite the name, the flowers can pale to medium lilac-pink. The leaves are large and pendulous, and the stems are usually round, rather than tetragonal (squared-off), often being pigmented and red/purple in colour. It is fully hardy and flowers slightly earlier (end of June onwards) than B. davidii, but can treated in the same way for pruning.

Buddleja alternifolia

Unlike virtually all Buddleja where the leaves are opposite, this one has alternate leaves. Sometimes called the Weeping Buddleja as it does resemble a willow. The arching stems of the previous years growth become covered in lilac flowers in late spring (May). These are in a spiral pattern all along the stem and not in a panicle or raceceme. It's deciduous so it is reduced to a bare skeleton in the winter but is really hardy, some claim even more hardy than B.davidii. Eventually it will grow into a small tree up to 4 metres across and 3 metres high, but can be pruned and shaped straight after flowering. Any later and it may not flower the next year.

Buddleja alternifolia 'Argentea'

Like the species but this cultivar has silvery-grey leaves (hence 'Argentea'). The flowers are a darker purple with reflexed petals and the scent is cleaner and stronger. It grows much slower than the species which is the only downside.

Buddleja aff. alternifolia 'Tsestangensis'

Buddleja tsestangensis, to give it the original name, is a white flowered form of B.alternifolia with grey, toothed leaves. It is also known under the name B. wardii KR4881 as some believe it may be a hybrid with B. crispa. It flowers slightly earlier than other Buddleja alternifolia and isn't fully deciduous in mild winters.

Buddleja caryopteridifolia

Not the easiest name, but this looks a viable alternative to the finicky B.crispa. Fully hardy but deciduous, it has greyish foliage and purple flowers. The scent is a bit like B.crispa, so very pleasant. It flowers late spring (May) and can flower again in the late summer or autumn.

Up close the individual flowers resemble B. alternifolia 'Argentea' and occassionally branches have alternate leaves. The cultivar shown could be a B. alternifolia and B.crispa cross, possibly arising out of a natural hybridisation sometime in the past. I suspect it is in fact the hybrid B. wardii, but it is currently being sold as B. caryopteridifolia.

The authentic B. caryopteridifolia has been described as a variety of B. crispa. There is more on this and other B. crispa varieties and hybrids HERE.

Buddleja colvilei

An unusual Himalayan Buddleja with the largeset flowers in the genus, each one about the size of a wiegela flower (about 1.5cm diameter) but with four petals. This particular cultivar has pink flowers with a white throat that appear late spring. It can grow into a big shrub if it winters well and gets hardier with age, but needs a sheltered spot to thrive. Young plants need extra protection over winter until they are fully established.

There are quite a few cultivars around now, mostly from wild-collected seeds, in shades of red and pink. The dark red 'Kewensis' is the most common (see below).

Buddleja colvilei 'Kewensis'

The cultivar 'Kewensis', selected at Kew Gardens, is more popular than the species. It has dark red flowers and deeper green foliage - one of the finest Buddlejas you can grow and hardier than the pink form, but it still needs a sheltered spot. Cover with fleece in the winter to protect the buds from frost as it is spring flowering, anytime between April and June depending on conditions.

Buddleja crispa

Pretty pink flowers and soft grey foliage, the leaves are almost heart-shaped. This is an attractive Buddleja that can grow quite large and woody. It is fussy though and needs a very warm south-facing wall to survive. It also can't take any water-logging over winter and prefers dry conditions in summer to enhance the silvery foliage.

I have grown mine in a large pot so it can be kept under cover all winter, although it is still fully deciduous. Flowers in June-July and you can get a second flush in the autumn of you dead-head.

There is more on this and other B. crispa varieties and hybrids HERE.

Buddleja fallowiana ‘Alba’

One of the species more closely related to B. davidii, B. fallowiana has felted grey leaves and white felted stems, too. The species has lilac flowers but the white, or alba, form is more commonly grown. This white form also tends to be hardier, though nowhere near as tough as B. davidii and it loses all its leaves in winter. Winter water-logging is lethal.

Buddleja forrestii

B. forrestii is a highly variable Himalayan species and is closely allied with B. macrostachya. There are quite a few separate cultvars of these species and their origins are often unknown. In general, both are large shrubs to small trees with long panicles of white, lilac or purple flowers. The foliage also tends to be large and dark green, the stems tetragonal and winged.

My plant is from Roseland House Garden and Nursery in Cornwall. So far it seems fairly hardy and kept its leaves over winter. A large and robust shrub, it flowers July and has off-white flowers with a mauve flush in the bud.

Many species were sunk into B. forrestii including B. pterocaulis (also called B. longifolia Gagnep.) and B. limitanea (see below), which has caused some confusion. Some plants sold as B. pterocaulis longifolia, which is not a legitimate name, are a form of B. forrestii, and some are B. salviifolia Alba (see below), a complete mislabelling.

B. macrostachya is easily mistaken for B. forrestii as they are so similar. Only close examination of the flowers can distinguish them (see below).

Selected pages from A.J.M. Leeuwenberg (1979) The Loganiaceae of Africa XVIII: Buddleja - Revision of the African and Asian Species: B. macrostachya and B. forrestii.

Buddleja globosa

A South American Buddleja from Chile and Argentina. It is a large shrub with glossy green leaves and intriguing golf-ball flowers about 15mm in diameter. It is probably the most popular garden Buddleja after B. davidii. Many cultivars are listed: Cally Orange; Cannington Gold; Lemon Ball; to name three. There is little difference except HCM98017 decribed below. There is also a variegated form with yellow spotted leaves. It is completely hardy in the UK and more or less evergreen in most of the UK. Flowers May to June and the bees love it.

B. globosa HCM98017 has very pale yellow flowers and smaller leaves.

B. araucana, formerly called B.nappii, is a closely related species with similar orange flowers but has brown down on stems and the underside of its narrower leaves. It is relatively uncommon in cultivation and it takes an expert to tell from B. globosa. In fact it has previously been known as B. globosa var. araucana and not treated as a separate species at all.

Both B. araucana and B. globosa are cyptically dioecious (see above) like the majority of New World Buddlejas, although the flowers appear to be hermaphrodite. The plants that are in cultivation have not been sexed.

There is much more about these two species on a separate page HERE.

Buddleja glomerata

From the semi-deserts of South Africa and often called Karoo Sagewood locally. It has puckered silver foliage and the tiniest fluffy yellow flowers in large plumes with a scent of cloves. This can tolerate cold but not too much damp. Sometimes also sold as Buddleja 'Silver Service'. Some consider it belongs in a separate genus, Chilianthus, along with B. saligna and B. dysophylla, as the anthers protrude beyond the corolla tube unlike all other Buddleja.

Buddleja lindleyana

Summer flowering Chinese Buddleja with pretty purple tubular flowers in pendulous panicles but they have absolutely no scent. Glossy small green leaves on a shrub that can grow into a small tree eventually. This species also suckers so can spread out if not kept in check. Pruning, where necesssry, should be in spring. More or less hardy but a sheltered position is better, often grown against a wall. It can be evergreen or lose its leaves in a hard winter.

Buddleja limitanea

Another summer flowering Chinese Buddleja. This species has been described as no more than a small variant of B. forrestii, but it is still often treated as a separate entity in horticulture. Pendulous panicles of mauve-purple flowers appear in late summer, the individual flowers are a bit larger than B. davidii. The leaves are smaller than the larger forms of B. forrestii, and the plants described as B. limitanea stay smaller, about three metres. This example is quite hardy, but can be cut back hard in cold winters. If pruning is required then it should be done in early spring.

There are a couple of different cultivars around, such as the one below which has pretty pink flowers. Another example is Buddleja sp. ACE2522, collected in China by the Alpine Garden Society.


Buddleja loricata

From South Africa and sometimes called Mountain Sagewood. It is a smallish shrub has rough strap-like leaves with a silvery underside. It is fully hardy, evergreen and doesn't even mind snow. It is grown mainly for its foliage but has interesting white flowers that come in June or early July. Pruning is optional but should probably be done straight after flowering; alternatively it can just be trimmed to be kept tidy


Buddleja macrostachya

A species with a wide range across the Himalayan region and south-east Asia. Until it flowers this species is indistinguishable from B. forrestii (see above for more details). There are several different plants available - this one is PAB4198 from Sikkim (northern India) with pink flowers. The species is highly variable and the flowers can be anything from white through to wine-red. Generally it flowers very late in the season, meaning a mild autumn is required for it to bloom.

Buddleja macrostachya is most easily distinguished from the similar B. forrestii by dissecting the flowers. In the photo (left) a B. macrostachya flower has been cut open to reveal the pistil and ovary. Note that the ovary (and later the seed capsule) is covered in tangled hairs (stellate-tomentose) and how the base of the style is also hairy. The interior of the corolla tube also has numerous hairs (villose) down to level with the ovary. In B. forrestii the ovary is glabrous or with very few hairs.

Due to the variabilty found in these two species gross features such as corolla tube length, panicle form and growth habit cannot be reliably used to effect a correct identification.

Selected pages from A.J.M. Leeuwenberg (1979) The Loganiaceae of Africa XVIII: Buddleja - Revision of the African and Asian Species: B. macrostachya and B. forrestii.

Buddleja nivea

From China again, this one is distinguished by its heavily felted leaves and stems. The inflorescences are in long cats' tail panicles but the individual purple flowers are unremarkable. It is mostly grown for its large felted foliage. Fully deciduous but quite hardy and it should be pruned hard in spring to keep it a small shrub.

There is also a pink-flowered form of B. nivea. The flowers are not any more outstanding and, although a pleasant shade of pink, are individually smaller and the panicle more open. The plant is,however, more floriferous than other forms and repeat blooms if dead-headed.


Buddleja nivea type stenostachya

Another form of B. nivea, this used to be considered a separate species and is still sold as such. The leaves have smooth edges and the stem tomentum is less floccose, but otherwise the shrub is very similar to the species type. The inflorescences are a little different though, and it has very narrow panicles, for which it is named (stenostachya means narrow flower spikes). The individual flowers themselves are very similar to the species - purple, hairy throated and with a very short corolla tube. Possibly not as hardy as the other forms of B. nivea.

Buddleja nivea var. yunnanensis

Not to be confused with B. yunnanensis, a distinct and much smaller Asian species. Very like the species type in many ways, although it will grow much bigger. The leaves are longer and more conspicuously serrated. The purple flowers are not particularly remarkable. Deciduous and hardy. There is the possibility that the Yunnan form of B. nivea has undergone a doubling of its chromosome number, from hexa- to dodecaploid (Moore 1960), and this could account for the size and vigour.
Ref: Moore R. 1960. Cytotaxonomic notes on Buddleja. American Journal of Botany 47: 511–517.

Buddleja officinalis

Unusually, this is a winter-flowering large shrub. Soft lilac-pink flowers open when the plant has few leaves. In summer it has large, long, soft and felted leaves, the stems also have brown felt so it is mostly grown as an attractive foliage plant. It loses most of its leaves for the winter. Mine flowered February, although this species can be in flower at Christmas provided it is in a particularly warm sunny position or kept under cover. Just hardy enough to grow in a sheltered spot, although the flower buds would be damaged by hard frost.

Buddleja officinalis is very similar to B. paniculata; the latter tends to have shorter leaves, which may be toothed.

Buddleja salviifolia

The leaves are very like sage, hence the name - called African Sagewood in South Africa where it comes from. Flowers in late spring, April-May, and can be blue, lilac or off-white - mine is a fetching blue. Just about hardy in southern UK, possibly not further north unless you have a very sheltered spot.

It is sometimes sold mis-identified as B.myriantha, which is a totally different Asian Buddleja.


Buddleja salviifolia 'Alba'

This particular Buddleja salviifolia Alba has unusual foliage very different to the form above. It has only tentatively been identified as a B. salviifolia Alba by Pan Global Plants, Gloucesterhire. The white flowers are similar in appearance as the blue cultivar and appear in spring at roughly the same time or sometimes a little earlier. From the same area as other B. salviifolia, which is known to be a very variable species. Its hardiness is untested but is evergreen if kept under cover.


Buddleja sterniana

Often considered a sub-species of B.crispa and is perhaps more correctly called B.crispa var. sterniana (B.farreri and B.agasthosma are also classified as B.crispa varieties). It is a spring flowering shrub with a lax habit. Leaves are grey felted and a little like B.crispa. Flowers are in early spring so are lost unless protected over the winter. In the recent harsh winters this has been cut right back and not flowered, but when it does the pale lilac flowers have a delicious scent.

There is more on this and other B. crispa varieties and hybrids HERE.



RETURN TO THE FRONT PAGE