When and How to Prune Buddleia Plants – 2 Methods

When and How to Prune Buddleia Plants – 2 Methods

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A little pruning never hurts plants, and buddleia bushes are no exception and they even benefit from pruning at least once a year to prevent bare stems.

When Buddleia are left unpruned, they quickly get more woody and produce fewer blooms as time goes by. You also end up with tall bare stems over 6ft tall with flowers well above head height. Pruning the buddleia in my garden is a yearly process carried out every year to maintain healthy looking plants with plenty of foliage and flowers.

Buddleia Globosa which should be lightly pruned in mid summer
Buddleia globosa should only be lightly pruned in mid summer by removing some of the oldest wood

There is just once exception to this process and that is with Buddleja alternifolia and Buddleja globosa with their famous round blooms. These two varieties flower on the prevous year’s growth so these need pruning mid summer but just removing some of the old wood, never hard prune these or you will remove the flowering stems.

Firstly, let’s cover the ideal time to prune all other buddleias which are types that most people have in the garden such as all davidii species:

The best time to prune buddleia

Pruning at the right time allows the plant time to recover without hindering new growth. Buddleia plants receive pruning as spring begins or late winter because the plant is still in the dormant phase. You ideally want to prune just as new foliage starts to shoot.

Also learn how to take buddleia cutting in this guide here

How to prune buddleia effectively

Buddleia that is pruned once a year in spring to maintain lots of foliage and flowers and prevent bare stems lower down

Take note of the variety you have to avoid pruning at the wrong time. As mentioned, varieties such as Buddleia globosa and Buddleia alternifolia bloom around late spring; therefore, you should lightly prune them mid summer removing the oldest growth. This is because the flowering stage is complete and new growth will not be affected. Remember as you prune, not to damage any new growth as it will bloom in the coming season.

When pruning I recommend using a sharp pair of secateurs and for thicker branches use a good pair of loppers or a pruning saw.

The most common buddleias which include davidii, should be hard pruned to around 30 from the ground in early spring, this should maintain a height of around 6ft tall by summer. If you want them to grow taller, I recommend pruning them to around 45-60cm above the ground. This will allow them to grow to around 8-10ft tall by summer.

You can also do a second pruning around May if the flowers have finished and you can often get a second flush of flowers and a longer flowering period. The second pruning cuts back the stems that have just finished flowering.

Because buddleia shoots spring from the base, you can cut the plant back by half or even much harder, personally I always prune them back to around 30cm to keep them compact. Don’t worry about pruning them too hard as they are very tough plants and will always spring back with new life. Together with cutting the plant back, there is a need to also remove woody growth.

Read next: Growing buddleias in pots

Deadheading buddleia

Another necessary process when dealing with buddleia is deadheading, as it encourages continuous blooms. Eradicating the spent flowers helps the plant redirect its energy into supporting the new blooms. Deadheading buddleia is not a one-day process, you’ll have to keep monitoring as the flowering process continues.

It sounds like a lot of work; however, if you don’t want the plant to develop seeds and overtake your garden, it is necessary. Butterfly bushes are beautiful, but they can invade your garden because of their fast reproduction rate.

Read next: How to kill a buddleia taking over my garden

Caring for buddleia after pruning

After pruning, a little aftercare ensures the plant recovers without problems. Remember to:

  • Keep the plants hydrated to prevent wilting in the already weakened plant.
  • Providing fertiliser or well-rotted manure to help the plant support the incoming growth.
  • Because pruning affects the plant’s vigour for a while, deal with any pest or disease infections immediately. I always recommend organic methods such as neem oil to avoid overpowering the plant with chemicals.
  • Mulching prevents the soil from losing moisture, regulates temperature and keeps some pests from attacking the plant.

Read next: Buddleia problems, common pests and diseases

In Conclusion…

The benefits of pruning your buddleia outweigh the disadvantages, therefore, don’t be afraid to do it and make sure you do it once a year in spring. Prune mature plants hard for you to enjoy abundant blooms all season and maintain the plant’s shape and encourage foliage. With that said, if it is already pruning season, grab your loppers or secateurs and get to work!

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