How to grow buddleia (butterfly bush)

There are larger and smaller varieties, good for borders and pots. Commonly known as the butterfly bush, the flower heads are full of nectar and are a magnet for many insects.

Flowers come in a wide range of colours including purple, blue, pink and white and even yellow. Flowers appear continuously for around four to six weeks in late summer.

How to grow buddleia (butterfly bush)

Grow buddleia in moist but well-drained soil in full sun. Deadhead flowers to encourage more to form and cut back hard in late spring to prevent the shrub from becoming too big. This will also ensure flowering occurs slightly later in the season, meaning there is plenty of pollen and nectar available for butterflies in late summer.

Related content:

• 10 buddlejas to grow
• Best shrubs for butterflies
• How to prune buddleja

Where to grow buddleia

Buddlejas will grow in almost any location – they're often seen growing out of brickwork and will happily colonise wasteland – in fact they're classed as invasive plants. However, to get the best out them as garden plants, choose a sunny spot, to encourage nectar-rich flowers and attract butterflies.

How to plant buddleia

If you have heavy clay soil, add a handful of grit to your planting hole for added drainage.

Watch Monty Don plant a buddleia in a border:

How to care for buddleia

If left to their own devices, buddleias can grow huge. They flower on new season’s growth, so give plants a hard prune in April or May, to cut out all the dead wood and maintain a good shape. This also encourages later flowering, which is good for butterflies such as the small tortoiseshell.

Watch Monty Don demonstrate how to prune a buddleia, in this Gardeners' World clip:

A high potash feed in spring will boost the flowering potential of your buddleia, but keep deadheading for a long-lasting flowering period. This will also prevent any unwanted spread of buddleia seedlings.

Watch Monty Don demonstrate how to deadhead buddleia in this clip from Gardeners' World:

How to propagate buddleia

Many varieties of buddleja will self-seed freely, but may not stay true to type. You can also propagate from semi-ripe buddleia cuttings in summer and hardwood cuttings in autumn.

Growing buddleias: problem solving

While relatively trouble-free, it's worth noting that buddleijas are on the invasive plants register and will readily escape onto train tracks, scrub land and into brickwork.

Buddleia varieties to try

• Buddleja davidii ‘Summer Beauty’ – a small variety, with deep pink flowers and narrow, green-grey leaves. It’s perfect for growing at the front of a border, or in containers.
• Buddleja davidii ‘Santana’ – with variegated leaves and wine-red flowers from July to September.
• Buddleja × weyriana 'Sungold' – unusual Buddleja with round clusters of golden yellow flowers with a strong fragrance.
• Buddleja davidii 'Ile de France' – deep purple flowers appear from July to September.
• Buddleja davidii ‘Buzz Sky Blue’ – compact and easy to grow with deep-blue flowers. Suitable for small gardens and containers.
• Buddleja alternifolia – different to the more familiar Buddleja davidii, the branches are slender and arching, bearing dense clusters of soft lilac-purple or pink fragrant flowers. The Royal Horticultural Society has given it the prestigious Award of Garden Merit (AGM).