How to grow buddleia

How to grow buddleia

Find out all you need to know about growing buddleja, in this detailed Grow Guide.

A table displaying which months are best to sow, plant and harvest.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Plant
Plant

Do not Plant in January

Do not Plant in February

Do not Plant in March

Do not Plant in April

Do Plant in May

Do Plant in June

Do Plant in July

Do Plant in August

Do Plant in September

Do not Plant in October

Do not Plant in November

Do not Plant in December

Flowers
Flowers

Plant does not flower in January

Plant does not flower in February

Plant does not flower in March

Plant does not flower in April

Plant does not flower in May

Plant does not flower in June

Plant does flower in July

Plant does flower in August

Plant does flower in September

Plant does not flower in October

Plant does not flower in November

Plant does not flower in December

Cut back
Cut back

Do not Cut back in January

Do not Cut back in February

Do Cut back in March

Do Cut back in April

Do Cut back in May

Do not Cut back in June

Do not Cut back in July

Do not Cut back in August

Do not Cut back in September

Do not Cut back in October

Do not Cut back in November

Do not Cut back in December

  • Plant size

    2m height

    1.5m spread

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

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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

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 on Buddleja 'Buzz Magenta'
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 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

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