Last updated on January 25th, 2022
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Growing Buddleia alternifolia (Butterfly Bush)
Most of us could quickly identify the hugely common, but extremely popular Buddleia davidii and some may have seen the new dwarf Buddleia varieties but most will not recognise or even have heard of a Buddleia alternifolia (also known as the alternate-leaved butterfly bush).
Originating from China, this large deciduous shrub or small tree has arching branches that nearly touch the floor and produce clusters of sweetly scented purple-lilac flowers along its weeping branches. It can be grown as a weeping standard but ensure you stake it with a strong stake that is able to support the arching branches. It also looks amazing when grown as a hedging shrub.
- Foliage: Deciduous
- Habit: Weeping arching habit
- Prune after flowering (NOT IN SPRING)
- Eventual height and spread: 4m x 4m
- Sweetly scented purple/lilac flowers in early summer
- Ideal for wildlife gardens and attracting bees and butterflies
The highly scented lilac-purple flowers (like all other types of Buddleia) are high in nectar and are extremely attractive to a variety of our much-loved butterflies, our bees that need our help and other beneficial insects that pollinate our plants.
Photo Source: wikimedia.org
They do best when planted in a more sheltered area although they are extremely hardy and will grow in colder, more exposed areas of the garden. Plant in fertile, moist but well-drained soil in full sun or partial shade. They will grow well in a south-facing position where some plants might fail.
Pruning Buddleia alternifolia
Unlike most other types of Buddleia, it is very important that you DO NOT prune Buddleia alternifolia in spring as you would with most other types. They usually flower in late spring to early summer, around March-April. These flowers are produced on the previous years’ growth, so pruning in spring would cut off all the previous years flowering shoots which you do not want.
Straight after they have finished flowering, cut them back with a good pair of pruners by around a third or even up to half. At the same time, you can prune out any diseased, damaged or overgrown shoots. Thicker older wood could also be removed right down to the base of the plant every few years to make way for new shoots. After pruning there should be plenty of time for new shoots to regrow over summer that will produce the flowers the following year.
In spring as the leaves start to shoot, apply a high in potash (potassium) granular feed such as Vitax Q4 or a quality rose feed to the base of plants with measurements as instructed on the packaging. This will help encourage flowering and give the plants a boost.
The easiest way to propagate Buddleia alternifolia is to take semi-hardwood cuttings in summer or hardwood cuttings in Autumn/Winter.