I love Buddlejas or butterfly bushes and I should warn you that once you start to grow these, you will probably want to grow more, and more. These wonderful flowering shrubs produce colourful, mostly cone shaped heads of flowers with a sweet honey-like perfume, which attracts butterflies and honey-eating birds. Most are sun-loving, evergreen shrubs which flower for many months in summer and autumn, and different varieties range in size from 1-5m high. They tolerate all soil conditions including heavy clay provided there is good drainage, and are hardy and drought tolerant once established. They do require full sun to flower at their best and although they are dry tolerant, aim to give them a good deep watering every one to two weeks during extended dry periods for the best flowering.
Buddlejas are very quick growing and require hard pruning after flowering to keep the plants compact and lush. Most varieties do best when pruned back to one third to one half of their original size after flowering. Plants that are not regularly pruned hard tend to end up woody, leggy and straggly. Dead heading their flowering cones during the growing season also encourages a longer flowering period. I grow over 20 varieties of Buddlejas at Sophie’s Patch and here are the main ones to look out for.
• Buddleja davidii cultivars are the most common varieties available. The larger varieties grow to 5m high with an upright bushy habit with flower colours from pure white, through pink and mauve to purple. Cultivar names include ‘Pink delight’ with delightful mid pink dense flower cones, ‘Black Knight’ with dark violet blue flowers and ‘Royal Red’ with burgundy red flowers. There are also some medium sized forms which grow to 3m high with smaller foliage called B. davidii ‘Nanho Blue’ and ‘Nanho Purple’. Their slender spikes of purplish blue or purple flower spikes appear for several months. Dead heading spent flowers will extend their flowering season however it appears more effective with these two ‘Nanho’ forms. These have long been favourites as their size is more appropriate for smaller gardens, however in recent years there have been more dwarf varieties released.
The dwarf cultivar range I have grown is sold under the cultivar name ‘Buzz’ and while they promise to only grow 1m high, I find they are more like 1.5+ m high. They smother themselves with flowers and being smaller are easier to dead head the old flowers, stimulating more flowers and a longer flowering period.
• Buddleja x weyeriana is also looking stunning in my garden at the moment. Instead of having cone-shaped heads of flowers, its flower spikes have globe shaped bunches of flowers along them, in cream or orange-yellow. Its flowers are still scented and a hit with the birds and butterflies, however it has a larger more arching habit.
• Buddleja lindleyana has light purple flowers borne in graceful drooping sprays which are more elegant than the dense conical flower heads of the B. davidii types. Its foliage is sage green and the bush grows to 3.5 m high.
• Buddleja salvifolia, also known as South African sagewood. It forms a large spreading shrub at least 3 m high and wide and smothers itself with huge clusters of smoky-lilac fragrant flowers on the tips of pendant branches in late winter and spring. The foliage is felted and grey-green, sage-like, as its name suggests. Flowering in winter, it will not attract butterflies however the honey eating birds love it.
• Buddleja ‘Spring Promise’ which starts flowering in late winter and continues on through spring, with very slender spikes of pure white flowers. The scent of these flowers is exquisite and is reminiscent of freesias. I have it planted on the path to my front door and I love it every time I walk past. Unfortunately I don’t find it very hardy and it gets tall and leggy and doesn’t respond well to pruning. So I find I need to replace it every couple of years but I still think it is worth growing, just for its scent.
• Buddleja crispa known as the Himalayan butterfly is another spring flowering variety. It forms a spreading shrub to 4m with large, heart shaped, downy silver foliage which is very attractive and makes the plant worth growing for its foliage alone. I grow it against a stone wall facing North-West, where many other plants have failed and it loves the hot baking situation. It flowers in spring and early summer with soft lilac pink flowers on short spikes and although not as visually stunning as some of the other flowers, it certainly warrants a place for its foliage. Unlike most of the other varieties I grow, it is deciduous however as it flowers on new growth, it likes to be pruned hard in winter.
• Buddleja alternifolia also flowers in spring with tiny mauve-pink fragrant flowers that are clustered along its slender weeping stems, giving it the common name ‘Fountain Buddleja’. It is a deciduous shrub with small foliage but as it grows it creates a stunning arching plant.
One word of caution which always makes me smile as I look at my plants, they are prone to caterpillar damage. Funny about that, on a plant grown to attract butterflies!? It reminds me of a story which a friend who works in a garden center tells, about how in years gone by he sold a lady a swan plant, renown to attract monarch butterflies. Within a few weeks she was back saying it was being attacked by caterpillars and wanted a product to kill the caterpillars with!? Rest assured when it comes to Buddlejas, the caterpillar damage is less noticeable on older plants.