Buddleia is a beautiful plant that produces large, showy flowers and attracts butterflies and hummingbirds. The flowers last for weeks in the garden, but people still have many questions about what to do with them once they have finished blooming.

Some people mistakenly believe that the only option is to dig up the plant and discard it but that would be wrong as Buddleia is a hardy perennial that will come back stronger each year with the right care.

This blog post will answer some of your questions on what to do with your Buddleia’s after flowering so that you can enjoy this colourful addition to your garden all year round!

What is a Buddleia?

Buddleia is a hardy perennial that grows throughout the world although they are considered invasive in Europe and Australasia. The genus Buddleja of flowering plants in the family Scrophulariaceae, with about 140 species.

Most species of Buddleia are shrubs that are under 5m tall, but some species are beasts that can even be considered trees as they grow to a staggering 30m tall!

In the UK, we have a shrub variety, and they are commonly known as butterfly bushes because they attract butterflies to the garden to feast on their plentiful nectar.

What Happens When Buddleia Flower?

It is hard to say how long a buddleia flower will last because it depends on where in the world you live and what your climate is like but over here (England), Buddleia flowers are the showiest around the late summer and they can last for around 6 weeks. In the UK, the shrubs can grow up to 12 feet tall but will typically be about three or four feet high if grown in a pot.

The bright, tubular flowers come in shades of blue, pink, purple and white with red throats that attract hummingbirds and butterflies for nectar as well as bees for pollen.

These blossoms last on the plant from a couple of weeks to a couple of months depending on the conditions.

What to Do Buddleia Butterfly Bushes After Flowering?

Once you have finished admiring the beauty of your buddleia and the blooms begin to fade it is time to start deadheading which will make your flowers last much longer.

Deadheading is a gentle pruning to remove spent flowers to help promote new growth. As the flowers begin to fade, take your clean, sharp secateurs and cut below the flowerhead but above any new shoots that may have appeared.

Continue to do this as each flower fades and you should have a beautiful Buddleia in bloom through to the autumn.

Deadheading is important, not only for promoting new growth but to prevent the plant from expending energy going to seed. Also, being invasive, you don’t want Buddleia’s spreading their seeds all over.

How to Prune a Buddleia

As opposed to deadheading after flowering, you will need to hard prune your Buddleia each year. This is best done after the last frost in your area which is usually around the time the plant has begun to show new growth. Buddleia can be susceptible to extreme cold once pruned so you will want to check the forecast and make sure that the cold has passed.

What You Need

  • Clean, Sharp Secateurs or Loppers
  • Gloves

Step 1 – Cut Back the Thick Woody Stems

Okay, now this is the part that you may feel is a little drastic, but I assure you that this is the correct way to do it.

Using your loppers or secateurs, cut back all of the woody stems to around 45cm tall, just above the newest leaf node or a sign of fresh growth.

Yes, that is right, all the way down to almost nothing even if there is new growth appearing above the cut. Just remember, once you have finished up your pruning, the Buddleia will resemble a stag’s antlers.

Also, remove any thin and weak looking wood from the previous years’ growth – these can be pruned back to the ground.

Step 2 – Mulch

Now is the best time to add a few centimetres of compost or mulch to help the soil retain moisture once the rains have begun to subside.

Step 3 – Water

Buddleias are drought tolerant and as such do not require frequent watering for them to thrive.

They will need watering during the spring when growth is at its strongest but not so much that the roots are constantly sitting in water as this will damage the plant. The soil should be moist, not soaking wet.

In the summer, Buddleia will only need occasional watering – a good indication of this is when you see the leaves begin to curl and wither so if you see this, your plant may need a good, deep soaking.

Hard Pruning a Buddleia

How to Prune Buddleia in Containers

Buddleia in containers can be treated the same as if they were in the soil. After the last frost, cut right back into the old wood above the newest shoot about 45cm tall.

As Buddleia flower on new growth every year, do not worry if you take your Buddleia down to almost nothing as it will come back stronger than ever.

Conclusion

Buddleia is a beautiful addition to any garden. With their bright, tubular flowers in a variety of colours that attract butterflies.

They can be grown either in the ground or containers, but both require hard pruning in the spring to maintain their shape and promote new growth.

After flowering, deadheading your Buddleia is important not only for promoting the growth of new flowers to extend the blooming season but it is also important for preventing Buddleia from expending its energy on seed production.

Garden Doctor Trev

Garden Doctor Tips

“Do not be afraid to prune your Buddleia hard – this promotes new growth, and your Buddleia will grow vigorously!”

“Check the weather forecast before you embark on your spring hard pruning, Buddleia can be prone to shock from colder temperatures!”

“Always deadhead your Buddleia as soon as the blooms begin to fade, this will extend the blooming season and prevent the production of seeds!”

“Do not overwater your Buddleia, make sure that the soil is moist and not soaking wet – unless they require a deep soaking in drought conditions!”

Frequently Asked Questions

Should I mulch Buddleia?

Adding mulch around your Buddleia is a good idea to prevent weeds from popping up and competing with your plant. Mulching also helps the soil retain moisture, if your buddleia is growing in more of a clay type soil, mulching probably isn’t required.

What kind of soil does buddleia need?

Buddleia grows best in loose, well-draining soil.

What time of year do you cut back butterfly bushes?

Buddleia should be cut back (hard pruned) in the spring just after the last frost. The only pruning you should do to your Buddleia in the summer months is deadheading to promote new growth and prevent seed production.

Should I Deadhead buddleia?

Yes, spent flowers should be removed as they have begun to fade. This is important to extend the blooming season so the plant can grow fresh flowers and not use its energy on creating seeds.

Should butterfly bushes be cut back for winter?

No. Buddleia should not be cut back for winter. Buddleia should be hard pruned after the last frost of the year as new shoots have begun to emerge. Pruning hard for the winter could be extremely detrimental to your plant.

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