Growing Buddleias for Wildlife

In the mid 19th century Pere Armond David, a French missionary, introduced into Britain a shrub that was to become one of the most useful additions to our gardens.  During his travels in Southwest China in 1869, David came across a plant known as ‘summer lilac’ and sent seeds of this rangy, sweetly scented shrub to Kew Gardens where they were quickly germinated.  The new shrub rapidly became a favourite with English gardeners and was named in honour of English botanist and clergyman Adam Buddle, and David, its collector.  Buddleia davidii is now one of our most commonly grown garden shrubs providing summer colour, scent, nectar and pollen for insects everywhere. 

More than 30 species of Buddleia are in cultivation in this country.  Many of them are tender and need a mild winter in order to survive the British climate.  Of all these species, Buddleia davidii, often known as Butterfly Bush, is the most commonly grown and new varieties in many colours are introduced every year.  There is no doubt that as gardeners we are spoilt for choice - hundreds of selections have now been made in shades of purple, pink, red and white.  All have many small, honey-scented tubular flowers which combine into a terminal, pyramidal spike which may be up to 30 centimetres long. Buddleia davidii is reliably hardy in most parts of the country but occasionally during bad winters bushes die back to the ground, but almost always grow again from the rootstock.

So with such a multitude of named varieties and colour choices, are all varieties equally attractive to insects?  Here many experts differ, and most have their favourites, but in general it seems that darker flowered varieties such as the popular 'Black Knight' do not perform quite as well as butterfly magnets as the paler colours.  My own experience with a selection of colours through white and pale pink to dark purple seems to bear this out, and I would always select a white such as White Butterfly or White Profusion as a first choice.  Of course the pale mauve species is hard to beat, but newer varieties have been bred for more compact growth or larger flowers.  Perhaps the answer is to visit your local shrub nursery when the Buddleias are in flower and see which ones the butterflies prefer. Not just butterflies appreciate B. davidii.  Honeybees, some moths, including hummingbird hawk moth, bumblebees and solitary bees all appreciate this plant, so a shrub or two near the vegetable plot brings pollinators galore.  However, if bumblebees are a priority, try Buddleia globosa, often referred to as Orange Ball Buddleia.  This species has a more robust structure than davidii, and can easily reach a height and spread of four or five meters.   Bumblebees love this plant, but few butterflies find it attractive.  It flowers in early summer, before the Butterfly Bush, and brings a welcome splash of orange to the shrub border. Buddleias are also surprisingly good for a variety of small birds including tits and warblers, as they will search for the many small invertebrates that are attracted to the flowers.

One of Buddleia’s attributes is its ability to produce hybrids between the various species, and some of these are very useful indeed.  A cross between B. davidii and B. globosa has produced Buddleia x weyeriana, a tall shrub with clusters of flowers somewhere between its two parents.  These appear in late summer and may continue to flower into the autumn.  The flowers are usually pale yellow although some varieties, such as Sungold, have a strange tinge of purple – a different and interesting shrub which attracts both bees and butterflies.  The B. x weyeriana varieties such as Margaret Price and Golden Glow are especially attractive to red admirals.  Plant one of these in your garden and you can be assured of visits from this most attractive of butterflies well into the autumn.

Many of the other Buddleia species are rather tender, but B. alternifolia is another beautiful and relatively hardy species.  It is an elegant shrub with gently arching branches, each bearing small clusters of pale purple, sweetly scented flowers along its length. This is definitely a shrub worth a place in any garden, but it is less attractive to butterflies than many of its cousins.  Buddleia fallowiana is equally pretty but is only frost hardy and best grown in a well drained soil or against a sheltered wall.  Its leaves are covered with white hairs when young, becoming grey-green with age.  However, it has been hybridised with the common Butterfly Bush to produce what for me is the best of all the Buddleias, especially where attraction to butterflies is a priority.  Buddleia Lochinch has grey-green leaves, huge panicles of mauve flowers and a heady, honey scent that fills the garden on a sunny summer day.  Butterflies flock to it, as do honeybees, bumblebees and some moths and it is easy to grow.  Definitely a variety to look out for and add to your wildlife garden if you have a space.

One of the joys of all the Buddleia species and hybrids is that they are easy to grow and maintain.  Late February into March is the time to look at the management of B. davidii, its varieties and hybrids.  They should be cut right back to just above ground level at this time – this may seem harsh, but it is essential in a small garden, as they are robust shrubs and can outgrow their allotted space in a few years.  They flower on new wood, so this annual pruning ensures that they have large fresh panicles of flowers every summer.  Dead heading, if you have the time and patience, keeps them flowering for longer, or if you have space for more than one, try cutting back individual shrubs at intervals.  I cut the first in my garden in late February, and work my way through the others at three weekly intervals.  Those cut back in April continue to flower well into the autumn.  Buddleia globosa can also be cut back hard when required, but B. alternifolia should have just the flowering shoots removed once the flowers have faded.  Propagation of all varieties is easy, as cuttings will root at almost any time of year.  Semi-ripe cuttings taken in the summer and inserted into a mixture of compost and sharp sand take very readily, and are usually ready to plant into their final places the following spring.   Buddleia also germinates easily from its fluffy seeds. 

As wildlife gardeners we have a lot to thank Armond David for.  Without Buddleia our gardens would lack the main summer nectar source for the larger species of butterfly.  The shrub that bears his name is a fitting tribute to an intrepid collector, and a must for every garden.

© Text and photographs Jenny Steel 2017