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How and When to Prune Buddleia Butterfly Bushes

Anthony enjoys spending time in the workshop, kitchen, garden, and out fishing. Many of his DIY projects are featured in his yard.

Tiger Swallowtail Butterfly

Tiger Swallowtail Butterfly

Attracting Butterflies With Butterfly Bushes

What can be better for attracting butterflies than planting butterfly bushes? Colorful, hardy and easy to care for, this flowering shrub blooms profusely throughout the summer and into the early fall.

Woody stalks with pointed green leaves shooting up in the spring are followed by long cone-shaped flowers that burst from its tips in the summer. Butterflies, bees and other pollinators flock to feed on the nectar-filled flowers, transforming a blooming butterfly bush into a horticultural epicenter of insect activity.

"Butterfly bush" is the common name for the buddleia species of flowering shrub, and it is the perfect plant to complement the annual and perennial flowers in your butterfly garden. New cultivars are available in a variety of colors with blooms ranging from deep purple and bright fuchsia to flowers of creamy yellow and white.

Blooming butterfly bushes are magnets for attracting butterflies and hummingbirds. Plant several in different colors, and the butterflies will flutter into your garden.

This guide will break down how and why you should prune your butterfly bushes.

Black Swallowtail Butterfly

Black Swallowtail Butterfly

How and When to Prune a Butterfly Bush

Butterfly bushes grow vigorously and thrive in full sun. Plant these shrubs in well-drained soil and in areas where they will receive a lot of sunshine throughout the day. Once established, the buddleia plant is relatively drought tolerant. Our plants grow very well in a rocky, dry area of our yard.

We planted several different varieties of butterfly bush in our gardens, primarily as accent plants in perennial borders and in a naturalized area that includes mostly native plants. Though the buddleia is not native to our area, the pointy dark-green leaves and the weed-like appearance of the shrub fit right into naturalized setting.

Fritillary Butterfly

Fritillary Butterfly

Pruning Butterfly Bushes

Like many other flowering shrubs, the butterfly bush must be pruned at the right time of the year to control it's shape and to encourage the most blooms. Buddleia plants should be pruned twice a year: the first pruning is a hard-cutting in the spring, with a second pruning in the fall to cut away the spent flowers after the blooms fade away.

The First Pruning

Cut back all of the woody stalks by about two-thirds in late winter or in early spring, and remove any weak shoots sprouting from the ground. This hard pruning encourages stronger growth at the base of the plant, producing new shoots with flowers developing at their tips throughout the summer.

As flowers bloom and fade during the growing season, deadhead any spent flowers to reduce the chances of self seeding.

The Second Pruning

In the fall, prune away all of the tips to remove any faded flowers and developing seeds. In some areas, buddleia has become an invasive pest. Deadheading and removing the spent flowers before they go to seed is an important step in reducing the chances of butterfly bushes escaping from the garden and into the surrounding fields and woodlands.

A beautiful Swallowtail butterfly visits our Buddleia Butterfly Bush

A beautiful Swallowtail butterfly visits our Buddleia Butterfly Bush

Are Butterfly Bushes an Invasive Plant?

If the butterfly bush has a drawback, it is the potential for becoming an invasive pest. These bushes produce a lot of seeds. After the flowers fade in the fall, the seeds are dispersed by birds and by the wind. Some states list buddleia as species of special concern due to their ability to reproduce and spread, and we have found a few "volunteer" plants sprouting up in our New England gardens. So far, we have not found any of these plants in the woodlands surrounding our property.

Check with your local Department of Agriculture to determine if the buddleia butterfly bush is considered as environmental threat in your area.

Cutting the stalks back in the spring and deadheading the spent blooms not only encourages butterfly bushes to produce more stalks next year (and more flowers) but also prevents the plant from producing seeds. Hard pruning also helps to control the size and shaping of the plant, and I also selectively trim wayward stalks during the spring and summer.

Read More From Dengarden

Our Buddleia butterfly bush in full bloom

Our Buddleia butterfly bush in full bloom

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Questions & Answers

Question: In the middle of August, can I cut off the faded brown flowers of my butterfly bushes after the purple is gone? Will it encourage new ones in time for the Fall?

Answer: Pruning away the spent flowers prevents the plant from producing seeds, and can encourage new growth with new blooms.

Question: I have 15-year-old buddleia davidii that have not been hard pruned in many years. If I cut my buddleia butterfly bush back hard, will they survive? They are 15 feet tall at this point!

Answer: Hard pruning can stress a mature plant. Instead of cutting back the entire plant, prune selectively to re-shape the shrub over several seasons. Start by removing any deadwood and up to 1/3 of larger, overgrown stems. This will help to encourage new growth.

Question: Can I cut and shape my bush in the late fall?

Answer: Yes, absolutely! Butterfly bushes can be pruned in the late fall after the flowers fade. In addition to shaping the bush, cutting away the dead blooms reduces the chances for the plant to re-seed and spread in areas where the Buddleia is becoming an invasive pest.

Question: Deadheading these flowers, encouraging new blooms may seem good to us humans, yet I have noted that a great many birds eat these seeds over the winter. Should we not consider the greater picture, of the effects of our plantings?

Answer: Buddleia are considered as Invasive Species in many areas of the country. Deadheading the spent flowers before they produce seeds is one method for controlling the unwanted spread of these plants. Seeds that are ingested by birds can be deposited elsewhere, helping the plants to spread. We let many of our perennial plants to go to seed to help feed the birds in winter but since Buddleia can spread in our area, we will deadhead the spent blooms. In spite of the deadheading, we occasionally find a volunteer growing in the gardens.

Question: Can I prune my Buddleia bush before budding to thicken it up?

Answer: You can remove any weak or wayward stalks, or thin out an overgrown bush. This will help to encourage the plant to put more energy into the other stalks.

Question: Can I cut my Buddliea down to the ground? Will it make the bush bloom stronger ?

Answer: I cut back all about two-thirds of the stalks in late winter or in early spring. I live in Connecticut. It's mid-March and I'm pruning my butterfly bushes today. I'll remove any weak shoots sprouting from the ground. This hard pruning encourages stronger growth at the base of the plant, producing new shoots with flowers developing at their tips throughout the summer.

As flowers bloom and fade during the growing season, I'll prune away the spent flowers to reduce the chances of self seeding.

Question: It's May 30th and I live in Connecticut. Can I prune my butterfly bush now? It's about two years old and never had flowers, and I've never pruned it. It's about a foot high and round.

Answer: I live in Connecticut too, and my butterfly bushes have already sprouted lots of new growth. Buddleia bloom on new growth so if you prune off the new growth, your risk reducing this year's flowers -- or at least postponing summer blooms until early fall. Since your plant is only one foot tall, it probably doesn't need much pruning unless you're trying to control its shape. They also love full sun and too much shade can reduce blooms.

Question: Can I cut back my butterfly bush in May?

Answer: Butterfly bushes bloom is very tolerant of pruning, and can be cut back at almost anytime. Some selective pruning in late spring can still encourage new growth that will produce flowers this season. Since it's already May, consider a lighter pruning rather than cutting the plant down to the ground.

© 2013 Anthony Altorenna

Tell Us About the Butterflies in Your Garden

B.j. Murrell on October 14, 2018:

What is a butterfly house ! I have butterfly bushes , pentas, lantana and more butterflies than one can count... humming birds too!

I live in Central Louisiana ! I think I need a butterfly house

Judy T on October 18, 2017:

Well I live or vacation at our cottage in June and September/October and enjoy the Monarchs as they migrate south along Lake Huron in Ontario - and our purple butterfly bush is the best shrub for a constant show. Unfortunately I am not here in later winter to do the first pruning but the shrub is immense and I will take your feedback to dead head the spent blooms and proceed with gentle pruning as needed.

getmoreinfo on June 27, 2013:

I have seen butterflies in my flower garden, it is interesting how they are attracted to certain types of plants.

Klinetka on June 26, 2013:

I like the idea for butterfly house - great idea

mymoodswings on June 26, 2013:

.... love butterflies... and the idea on the butterfly houses... would also want to try planting those flowering bushes,,, but a bit concerned about the butterflies attracting snakes...

mrdata on June 23, 2013:

I love attracting butterflies in my garden! Thanks for your information!

Yamin Joe on June 22, 2013:

I enjoyed very much reading in your lens also looking at the lovely Butterflies, your lens inspired me to make good quality lenses.

DebMartin on June 22, 2013:

I've never heard of a butterfly house. Well you learn something new every day. The butterfly bushes I have in my garden have invaded my yard from the wilds. They are orange. But they do the trick. The butterflies love them.

SevenSistersRoses on June 20, 2013:

First time finding out about butterfly houses. Would make a great gift for my mom. She loves them. Thanks and congrats.

Wilf Catt from Leicester, England on June 20, 2013:

An excellent lens. Here in the U.K., Buddleia has spread all over the railway system and takes hold in the smallest of crevices. I have an example in the garden which produces flowers in the form of orange balls of about one inch in diameter - this is great as it doesn't produce huge volumes of seeds.

Susan Hazelton from Summerfield, Florida on June 20, 2013:

I think butterfly bushes are great. They're pretty to look at and best of all they attract butterflies. The addition of how to make a butterfly home was great.

jlshernandez on June 20, 2013:

I have a butterfly bush in our backyard and it grew twice its size in a year. The lavender cone-shaped flowers are lovely. I will make sure this gets pruned in the winter. Thanks for the tips and congrats on LOTD.

anonymous on June 20, 2013:

i want a butterfly house!

Renaissance Woman from Colorado on June 20, 2013:

Congrats on LotD! I'm all for any plant that attracts butterflies to my yard. Appreciated all of these resources. Very happy to see your feature and honors.

marktplaatsshop on June 20, 2013:

Thanks for sharing a great lens on the butterfly bush, I used to have a pink delight but now have a black knight

Stephen J Parkin from Pine Grove, Nova Scotia, Canada on June 20, 2013:

We have one large butterfly bush near the side of our house and yes it does attract the butterflies. We get a lot of the Anise Swallowtails like the one in your first picture. Well done on the LOTD!

pawpaw911 on June 20, 2013:

Congratulation on LOTD. I have one Butterfly Bush, and it was planted during a harsh weather year, so it is just now starting to flourish. This information is very helpful.

Sweetbunny LM on June 20, 2013:

Never saw a butterfly house before.

smsr0100451 on June 19, 2013:

I love butterfly but never thought about how to attract them. Thanks for a nice lens. Also congrats to LOTD.

Anthony Altorenna (author) from Connecticut on June 19, 2013:

@rattie lm: The invasive seedlings are a drawback to the butterfly bush, but pruning off the spent flowers before they go to seed helps to control the plant from spreading.

anonymous on May 29, 2013:

I was thinking that the Buddleia had the look of something wild and can see how it can blend well with wild friends. I love the color assortment and of course that it attracts butterflies as an "epicenter", very cool use of words there and great instruction for trimming this dream come true plant for nectar lovers, I would guess they are also popular with humming birds. I smiled when I saw your title and thought of your butterfly make them a home and plant a garden for them even! Already shared on FB, because you always give the best information! :)

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