Buddleia is an easy and fast-growing shrub, that will suit any garden where there is sun and well-drained soil.


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.

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Where to grow buddleia

Red admiral butterfly (Vanessa atalanta)
Red admiral butterfly on Buddleja 'Buzz Magenta'

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

Pruning Buddleja

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

Propagating Buddleja by hardwood cuttings
Propagating Buddleja by semi-ripe cuttings

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 invasive plants and will readily escape onto train tracks, scrub land and into brickwork.

Buddleia varieties to try

How to grow buddleias - varieties to grow
How to grow buddleias - varieties to grow

Frequently asked questions

Where is the best place to plant a buddleia?

The sunniest spot in your garden is the best place to plant a buddleia. A sunny spot will result in the best flowers. You should also avoid windy spots, as strong summer gales could result in branches breaking off or the roots becoming exposed. When you purchase your buddleia, check its full-grown size and plant it with enough space to grow.

Is buddleia a tree or a bush?

Buddleia is not a tree, it is technically a shrub but is commonly known as the butterfly bush.

Are buddleia a problem?

Buddleia are invasive plants, but if pruned and maintained in the garden they should not cause a problem. Buddleia can make a stunning addition to your garden, as well as producing flowers full of nectar for pollinating insects. 

Can I move a buddleia?

Buddleia are tough shrubs and should survive being transplanted. The best time to move a buddleia is in March or around mid-autumn when the foliage has died. Cut the buddleia back and water well the day before transplanting. Then dig it up, move to a well-prepared planting hole and water thoroughly.

How fast does buddleia grow?

Buddleia is a fast-growing shrub that can put on a couple of metres of growth or more in a year, but it can be pruned back to a low framework of stems in early spring. Grown from seed, it is even possible that buddleia may produce flowers in the first year.