Plant of the week: Buddleia

I pondered this week about what would make our plant of the week and nearly succumbed to the gorgeous blue flowers and red autumn foliage of Ceratostigma willmottianum Forest Blue but on looking around all this week all I seem to have noticed was the thriving buddleia bush.

Given that the common name of this shrub is the ‘Butterfly Bush’ as it attracts butterflies into the garden as they seek out the potent nectar, it left me wondering what is it exactly that makes this more attractive than other plants in the garden.

Butterflies basically adore Buddleia because it produces nectar that has a higher content of sucrose, glucose, and fructose than many other garden flowers, in particular Buddleia generally has a higher sucrose level (two or three times higher than fructose or glucose) and that is what attracts butterflies, however Buddleia do not produce much nectar, which is why you see butterflies spending so much time on a particular plant. It also appears from researching into this that visitation rates were lower on white or pale lavender flowers and greatest on those having red, pink, or lavender-pink flowers. So it is well worth having a variety of specimens to encourage different species of butterfly which is particularly important as butterfly numbers are in decline.

Effectively then the Buddleia is the equivalent of a high visibility filling station with its large flower heads acting as advertising beacons, enticing butterflies to sample their sweet wares. So with one or two in the garden you will be attracting and supporting them as well as enjoying the beauty of their coloured wings while in motion and recharging until the next flight.

This easy to grow shrub is also deer, rabbit and drought tolerant so pretty handy for those who may be forgetful re watering or have an abundance of our floppy eared friends who enjoy dining on your plants. I have often seen Buddleia grow on the side of a building and they do well on wasteland where they experience tough growing conditions and they survived our recent hard winters. The key to keeping them manageable, is pruning. To ensure a healthy plant for the next season it’s important to prune back the bush to about 2 ft (0.6 m) tall, leaving two or three buds above the base. Late winter or early spring is the best time to carry this out (although for Buddleia Globosa pruning is done after flowering). Also, to encourage reflowering, remove old flowers as this will encourage new flowers and make for an even more spectacular sight and it will flower well into autumn.

Alternatively if you want a dwarf specimen go for the Buddleia ‘Buzz’ series which has a manageable height and spread of 120cm when fully grown.