The butterfly bush Buddleia (sometimes spelled “Beddleja”) also called the “summer lilac” is a very lovely bush, and many gardeners love butterfly bushes because of their colorful flowers, sweet smell and ability to attract bees, butterflies, and other pollinators.
Butterfly bushes are rugged shrubs hardy throughout North America, and that is both a curse and a blessing. Because the butterfly bush is so very vigorous, this popular landscaping plant is also considered invasive in many states. There some non-invasive Buddleia hybrids available. Here are a few of our favorites:
- InSpired Violet Butterfly Bush
- Lo & Behold ‘Blue Chip Jr.’ Butterfly Bush
- Sangria Red – Buddleia x Miss Molly Butterfly Bush
In this article, we will explore the pros and cons of planting and keeping the purple butterfly bush. We will also provide information on the selection, care, and control of this attractive plant. Read on to learn more.
Attributes Of The Butterfly Bush (Buddleia davidii)
According to garden expert Mr. Monty Don, the South American native Buddleia davidii was introduced to the UK in 1774.
Buddleia davidii is a beautiful, fast-growing semi-evergreen, perennial shrub usually stands between six and ten foot tall high. It has a spread of up to ten feet and an open, arching shape.
The young stems of butterfly bushes are somewhat furry, and leaves of some cultivars have an attractive, velvety texture.
The butterfly bush size, shape, and shade of the leaves vary greatly from one cultivar to another. Leaves range in size from 3″-5″ inches long and 1″-3″ inches wide. Coloration varies from very dark green to a grayish-green to a light silver/gray.
Like the butterfly bush leaves, the blooms also come in a wide variety of colors ranging from bright white to creamy yellow, pink, red, blue, lilac and deep purple.
The butterfly bushes bloom abundantly throughout the early summer and into the autumn and attract a wide variety of birds and butterflies like the monarch butterfly with its penetrating fragrant flowers.
The flowers grow in long flower spikes in slim clusters (panicles) which vary in length from five inches to one foot.
These bushes grow vigorously in any type of soil with almost any pH level and can survive in nearly every weather condition. Butterfly bushes like full sun and loose soil and are hardy in USDA hardiness zones 5-10.
Buddleia davidii survives extremely cold Iowa winters without mulch although try to plant them in spots protected from north winds and the cold.
Their rampant growth makes Buddleia undesirable in areas like California. Many states list Buddleia as an invasive species, but pruning can keep it in control.
How To Use The Butterfly Bush In The Landscape
Because butterfly bushes attract pollinators so well, it is very often used as the basis of a butterfly garden. The fragrant blooms are abundant, providing nectar for pollinators and hummingbirds throughout the summer months and well into the autumn if you take the care to deadhead the spent flowers throughout the blooming season.
The butterfly bushes have a pleasingly rounded form and make a nice hedge or backdrop for a natural garden planted with a wide variety of native plants that can provide habitat for local wildlife once it has been drawn in by the nectar feast offered by the summer lilac.
How To Care For A Butterfly Bush & Cultivation
No matter what your conditions, the summer lilac will probably grow well for you. The only conditions that will kill this hardy deciduous shrub are soggy soil and lack of sun.
Butterfly bushes thrive when provided with a loose, well-drained soil and plenty of full sun. They prefer a pH of 6.0-7.0, but this is not absolutely essential.
Buddleia care requires very little in the way of fertilizer. Butterfly bushes are quite drought tolerant and very cold hardy.
In the coldest climates, they may die back all the way to the ground during winter, but they will quickly spring to life with new growth and more blossoms than ever before when the weather warms up.
Planting The Butterfly Bush In The Garden
The rough and tough butterfly bush plant does not require too much attention to keep it in good shape. Below covers the basics of growing the buddleia plant in the garden.
- Butterfly bushes grow best when planted during late fall or early spring.
- They require medium fertile well-drained soil to grow.
- The main concern with the butterfly bush is space. Most types of butterfly bushes grow 6’–12′ feet tall and 4’–16′ feet wide. Always give the plant some extra room.
- Choose a space with partial sun and partial shade.
- The butterfly bush doesn’t require a lot of fertilizer, but when planting use a good compost while preparing the soil bed.
- When planting position the root ball at the same level as the soil surface.
- Give butterfly bushes a minimum distance of 10′ feet apart.
- Water thoroughly after planting.
- Once established the plants are drought tolerant
Planting Butterfly Bushes In Containers
Dwarf varieties of the butterfly bush do well when grown in containers. I particularly like to see these dwarf varieties grown as a tree. Val Bourne, an award-winning garden expert, recommends varieties like Black Knight, the Salvia Black and Blue, Peacock and Pink Delight for container gardening. When planting in containers:
- Choose a pot large enough to hold a fully grown plant.
- Make sure the container has a good water drainage system.
- Use any soil mix recommended for container gardens.
- When planting, plant the root ball at the same soil level.
- Water the plant well.
Tips Caring For The Butterfly Bush
These happy, fast-growing flowering shrubs with beautiful flower spikes need little to no care, but keep a few things in mind while waiting for those butterflies and hummingbirds to show up.
- Fertilize the plant well in the winter.
- Deadheading blooms should be your favorite pastime!
- Keep the plants at an appropriate size by trimming the edges to avoid overgrowth.
- Caterpillars eating leaves can cause Buddelia trouble. If their feeding is minimal and not harming the plant, leave them alone; otherwise, take the necessary measures to remove them.
- Water the plant freely when growing and sparingly at other times.
- Avoid using too much fertilizer; this will promote leaf growth rather than flowers.
- Do not try to move a butterfly bush from one part of the garden to another. These plants do not cope well with transplanting.
- Always be on the lookout to make sure your butterfly bush doesn’t start spreading like a weed. Trim as necessary.
Caring For Butterfly Bushes: Pruning For Best Results
The buddleia, because of its rampant growth makes it undesirable for some homeowners, that’s where pruning comes into play. Many shrubs like the Buddleia can keep their style and characteristics with some selective pruning.
Pruning can come in several forms – by the great pruner called winter, or by you with your trusty pruning shears.
For example, in Ohio last year I saw some smaller and very attractive Buddleia Davidii compared to those in the south.
The difference? The northern plants were killed to the ground during winter, returning again when spring arrived – and they looked fabulous.
Let’s look at when you can cut back Buddleia bushes. You’ll find some subtle differences in pruning depending on species.
Butterfly Bush Pruning in Spring
Correctly pruning a butterfly bush is of great importance. The varieties which bloom and flower in late summer and autumn, are usually varieties related to Buddleia davidii, and should receive a hard pruning every year in the spring.
By hard pruning, we mean removing the growth and shoots from the previous season’s growth. Cut them all the way back to within 3″ or 6″ inches of the older wood.
However, if you want to increase the size of butterfly bushes quickly, cut the summer’s growth back to about 6″ to 9″ inches long. Make sure you remove, cut and thin out all weak twigs.
In northern regions, winter may kill the growths to the ground. As long as the roots survive, new shoots and new growth should emerge and produce blooms the same summer, just in time for butterfly season.
Most varieties of butterfly bushes produce their flowers on the new shoots grown during the current year, but there are some exceptions – Buddleia alternifolia.
Pruning Buddleia After Flowering
Buddleia alternifolia loses its leaves and produces flowers on the older wood.
Buddleia globosa, and Buddleia Colvillei the evergreen, or semi-evergreen species also produce blooms on their branches from the previous season’s growth.
For this reason, the flower buds need to be “preserved ” and pruning should NOT BE DONE until after the flowering season has normally finished in June. The pruning is slightly different. Lightly thin and remove old branches at this time. Shorten long shoots.
After 5 or 6 years butterfly bushes look tall, awkward-looking, and unattractive. The old wood needs to be pruned back hard in early April. Check out our favorite hand pruners for the job! You’ll lose blooms for one season, but new vigorous growth develops for next years bloom.
When the Crocus come out is a good time to prune indicator. New wood produced after this severe pruning is more vigorous and the flowers heavier than the ones produced on the two-year-old wood of the Buddleia.
Pruning Note: Some people are sensitive to contact with Buddleia foliage. It’s a good idea to always wear gardening gloves when pruning or deadheading these plants to prevent rashes and irritation.
Pests and Problems
The hardy, adaptable butterfly bush exhibits very few problems under most conditions. In sandy soils, they may be plagued by nematodes. In swampy conditions, they will develop root rot and die. In cases of extreme drought, butterfly bushes can attract spider mites.
In cool climates with extended periods of rain and dampness, downy mildew can develop on some cultivars (particularly those with very hairy leaves that retain moisture).
Root rot and drought stress can both be treated by a change in conditions. For root rot, till and amend the soil with peat, coco coir, sand and/or vermiculite to lighten it and improve air circulation. Alternatively, you may wish to move your butterfly bushes to a better environment.
For drought stress, provide an occasional deep soaking. Mulch heavily around the trunk (extending to the drip line of the branches) to help the soil retain moisture.
Because butterfly bushes attract a lot of beneficial insects, it is important to always use natural, gentle remedies when treating for any problem or pest. Neem oil is a good, natural remedy (available from Amazon) for a wide variety of infestations and ailments in the garden.
Pruning back to the ground is another possible solution for problems or pests. Because butterfly bushes have such a rapid growth habit, an extreme pruning in spring or summer could completely solve your pest or infestation problem and provide you with all new growth in a few short weeks.
Many Attractive Cultivars Of Butterfly Bushes Available
When choosing the right butterfly bush for your landscape, you will have many attractive choices. There are also a good number of hybrids and related species available.
Even though volunteer Buddleia and homegrown specimens are widely available – these plants are often misidentified.
It’s a good idea to obtain yours from an established and reliable nursery and it’s wise to know exactly what you are getting. Here are some of the top choices to look for:
Large Buddleia Varieties (6′ or Taller)
- Bicolor adds lots of interest to your garden with lavender buds that transition to peach, pink and yellow as they open and mature.
- White Profusion is extremely hardy and very easy to obtain. It is the most common among the white-flowered choices.
- Black Night has deep dark purple blossoms. It is the most readily available cultivar, and it has the darkest flowers.
- Lochininch is a hybrid cross boasting sweet-smelling, delicate purple flowers and silvery, furry leaves.
- Guinevere bears very fragrant purplish-black flowers coupled with pretty blue-green leaves.
- Pink Delight produces large panicles of pure pink blossoms. Its leaves are silvery.
- Royal Red bears long panicles of deep maroon flowers that butterflies love.
- Honeycomb has pretty yellow flowers and bright green leaves.
- Attraction features deep red blossoms and pretty leaves.
- Dartmoor has very large bunches of lilac flowers.
Dwarf Butterfly Bush Varieties (6’ or smaller)
- White Ball is the smallest butterfly bush. It attains a maximum height of 3 feet and bears bright white blossoms throughout the summer.
- Summer Beauty attains a maximum height of four feet and bears deep, rose-pink blossoms.
- Nanho Blue has blue flowers that range in shade from light mauve to deep indigo.
- Ellen’s Blue’ is a four-foot-high dwarf butterfly bush that produces pretty violet blue flowers
4 Species Related To Buddleia
#1 – Sage-Leaf Butterfly Bush (Buddleja salviifolia):
Buddleja plants have especially attractive foliage. The leaves are coppery-green in color and are very textured. Flowers are smaller in an unobtrusive shade of pale lavender.
This variety hails from South Africa and can attain a height of 20’ feet tall. Unlike its cousins, it flowers on old wood. If your objective is to grow attractive leaves with few flowers, severe annual pruning will help you attain this goal. If you want to encourage the demure blossoms, do not prune back old wood excessively.
#2 – Alternate-Leaf Butterfly Bush (Buddleja alternifolia):
Buddleia Alternifolia known as the “Fountain Butterfly Bush” can grow in Zone 5 reaching a height of 15′ feet as well as 15′ feet wide. Looking somewhat of a large, sloppy-looking shrub, however pruning and staking can easily turn the plant into a wonderfully graceful single or multi-stemmed small tree.
Different In Appearance
Alternifolia looks very different in appearance from other members of the Buddleia genus.
Distinctions of the Fountain Butterfly Bush:
- Weeping branches and alternate willow-shaped leaves
- Blooms on its old wood produced the previous year
- First to bloom of the Buddleia plants.
- Hardiest of the species
- Stronger scent than other buddleias
The delightfully fragrant, abundant cascades of lilac-purple flowers in clusters all along the backs of the arching twigs, begin in June, on pendulous arching sprays, creating an airy, graceful appearance.
Like all of the butterfly bushes, alternifolia prefers a light, well-drained soil in a sunny situation. It will flower in partial shade, though less profusely. The plant flowers quite well when left unpruned, but much more attractive and even better when shoots that have flowered are removed immediately after flowering.
#3 – Common Butterfly Bush (Buddleja fallowiana):
If you are more interested in leaves than flowers, this is a good choice. The interesting leaves are very furry and reach a length of 2“-4“. They have a pretty silvery cast. Flower panicles may be lavender or white and reach a length of 6”-8”. The plant grows 10′-15′ feet tall, but you can control its growth with pruning.
#4 – Lindley’s Butterfly Bush (Buddleja lindleyana):
This is a very small specimen that reaches a maximum height of 5’. It has dark, compact leaves and bears fragrant blooms in shades of lavender and deep purple. In addition to spreading by seed, this variety also spreads very quickly by suckers and will soon take over a given area if not kept in check. [source]
Is Butterfly Bush Really Invasive?
Sadly, this pretty, popular, easy to grow landscape addition really is very invasive. It spreads easily by seed into natural areas and onto disturbed soil.
It grows readily along roadsides, in cleared forest areas, along riverbanks and beside railroad tracks in many states. The plant colonizes rapidly and can interfere severely with essential natural development, such as forest regeneration and riverside habitat.
In some states this bush is considered a Class B noxious weed, making buying and selling of it illegal. Some weed control boards encourage people who have Buddleia bushes to do away with them or at the very least keep flowers carefully deadheaded to prevent the spread of seed.
Check with your local authorities to determine their status in your area.
The State of Oregon after a rigorous ban on the planting of Buddleia has amended their list to now allow planting of some non-invasive Buddleias which are listed below. These varieties produce less than 2% viable seeds. Check with your local garden center to see if they carry them:
- Buddleja ‘Asian Moon Butterfly Bush’
- Buddleja ‘Blue Chip’ from Proven Winners
- Buddleja ‘Blue Chip Jr.’
- Buddleja ‘Ice Chip’ (Formerly ‘White Icing’)
- Buddleja ‘Inspired Pink’
- Buddleja ‘Pink Micro Chip’
- Buddleja ‘Purple Haze’
- FLUTTERBY GRANDÉ™ Blueberry Cobbler Nectar Bush
- FLUTTERBY GRANDÉ™ Peach Cobbler Nectar Bush
- FLUTTERBY GRANDÉ™ Sweet Marmalade Nectar Bush
- FLUTTERBY GRANDÉ™ Tangerine Dream Nectar Bush
- FLUTTERBY GRANDÉ™ Vanilla Nectar Bush
- FLUTTERBY PETITE™ Snow White Nectar Bush
- FLUTTERBY™ Pink Nectar Bush
How Does Butterfly Bush Reproduce and Grow?
If you let the flowers go to seed, they will toss large numbers (40,000 per panicle) of winged, lightweight seeds into the wind. These can fly for miles and may land in water to be carried even farther away from the parent plant.
When these seeds hit the soil, fully eighty percent of them will germinate and grow very quickly. Most will produce their own seeds during the first season, so it’s easy to see that without controls, the entire landscape could quickly be taken over by Buddleia planting.
These plants also propagate readily from cuttings (broken branches) and from damaged roots, so when they take root along waterways they can easily be spread in the form of damaged limbs and roots after storms and severe flooding.
Because of its robust nature, it is very hard to do away with this plant once it becomes established. If seeds do not germinate right away, they can remain viable for 3-5 years. If you cut down one tree, the roots go into overdrive and you soon have a forest. If you dig up the roots and happen to leave a bit here or there, you will soon have many new trees!
How Does Butterfly Bush Impact Natural Habitat?
Butterfly bushes and plants seem to thrive in very challenging conditions and can overcome poor soil conditions, drought and more.
In fact, they seem to take hold more successfully under these conditions and often do not germinate and grow in a well-maintained landscape with enriched soil.
This means that summer lilac can take over barren areas where nothing else will grow.
While it might seem a good thing to have a rapidly growing plant quickly inhabit burned out or recently logged forests, flooded out river banks or unsightly settings, such as railroad easements, that really isn’t true.
When Buddleia takes hold, it prevents native plants from growing.
This means less food and less habitat for native species of birds, beneficial insects, and other wild things.
While you might think that a dense thicket of butterfly bush would be an ideal living place for all kinds of wildlife, this is actually not true.
The bushes provide lots of nectar for adult insects, but they do not provide a complete habitat.
6 Ways To Control Butterfly Bush
#1 – Choose a different plant! If you don’t have the butterfly bush, don’t plant it. Check with your local agriculture extension to identify the most desirable types of deciduous, flowering shrubs for your area. In some cases, specific cultivars of butterfly bush may be acceptable.
#2 – Seed Control: If you have a butterfly bush, take great care to avoid letting it go to seed. Deadhead vigorously and aggressively. Dispose of the spent flowers properly by either sealing them in a plastic bag and putting them in the trash or burning them.
If you deadhead after the flowers have begun to go to seed, put a plastic or paper bag around the pinnacle to prevent accidental dislodging and spreading seeds.
#3 – Seedling Control: If you have a butterfly bush, it will surely try to spread by sending out runners. You can pull these up or dig them up. Alternately, simply keep them closely mowed so that they never mature, but don’t expect them to give up and die. They won’t!
Keeping a heavy layer of mulch all around the shrub may help prevent them rearing their enthusiastic little heads, but watch out along the perimeter of your mulch and tackle them when they ultimately turn up!
#4 – Enlist Goats! Goats will eat saplings and seedlings as they appear, and they will keep them mowed off at ground height. If you are able to keep goats, they will keep their area free of unwanted butterfly bush and other unwanted plants like poison ivy.
If you are not able to keep goats on an ongoing basis, this is not a permanent fix. When the goats leave, the plants will come back. Borrowing or renting goats temporarily can be a good first step in control if you follow up with chemical control.
#5 – Use Herbicide: You can use products such as Roundup or Brush-B-Gon to control Buddleia somewhat. Spray seedlings and saplings with these products as you would any weed. To get rid of a mature plant, cut it back to the ground and then paint the surface of the stump with the product. After treatment, check back every few days and re-treat as needed.
#6 – Dispose of all parts of the plant properly! Don’t leave cut or broken branches lying on open ground. They will take root. Don’t toss roots, root balls or broken branches along the roadside or in any other wild area. They will quickly take hold and colonize the area. Bag up roots and branches for trash collection or to be sent off for composting. Alternately, you could burn them. [source]
Why Is It So Important To Avoid Planting Invasive Plant Species?
Although you might not realize it, your little slice of the planet – no matter how small – can greatly influence the natural environment for local native species. When you plant an invasive plant species, such as the butterfly bush, it negatively impacts food sources and habitat for local wildlife.
In fact, when a non-native plant takes the place of a native plant that is naturally designed and adapted to feed and house wildlife in a given area, it can reduce food sources by as much as 75% according to Professor Doug TallamyProfessor Doug Tallamy, PhD who is the chair of entomology and wildlife ecology at the University of Delaware.
Doctor Tallamy says that there are three main problems connected with the butterfly bush:
#1 – Butterfly bushes travel! As we have seen, these vigorous, hardy, highly adaptable plants can travel far and wide in great numbers. They are more rugged than most other plants, and they have no trouble crowding out native plants that naturally provide food and habitat for local fauna.
These bushes have easily spread to engulf Superfund sites that were intended to be re-grown as grassland. They have also completely taken over some of the Hawaiian islands. This sad state of affairs has negatively impacted and displaced countless native species of beneficial insects and birds.
#2 – Butterflies cannot complete their life cycle on a butterfly bush. These plants provide lots of tasty nectar for butterflies, bees, lady-bugs, hummingbirds and other creatures that enjoy nectar, but they are not host plants. Butterfly caterpillars cannot eat the leaves of these bushes. Without caterpillars, the trees do not provide adequate food for many types of birds.
#3 – Excessive numbers of Buddleia will cause the food web to collapse. When you add to the number of butterfly bushes in existence, you actually make life harder for local fauna to live. Even though it may seem that these pretty, fragrant, flowering bushes would enhance local habitat, they do not.
They are rather like a baby cuckoo bird in that they take up space and resources intended to support the rightful inhabitants of a given space. This eventually leads to the death of those inhabitants. [source]
Should You Plant Butterfly Bush?
According to the Old Farmer’s Almanac, most types of Buddleia are considered invasive in most parts of the United States. In many areas, it is considered a noxious weed. For this reason, the Almanac no longer publishes a list of recommended varieties. Instead, this esteemed source of information states that it does not recommend planting butterfly bush. [source]
For this reason, if you do not already have a butterfly bush, you and your landscape would probably be better off with another choice. If you do have one, it’s probably best to make the most of it by keeping it in check and surrounding it with native host plants that can support the beneficial pollinators and wildlife it attracts. Some examples include:
For more information on successfully planning and planting a bird and butterfly garden visit the USDA Natural Resources Conservation Service website. The New Jersey Audubon Society also offers helpful advice.
We hope that you have found this information useful in making smart decisions surrounding the selection, care and control of the lovely and sometimes invasive Butterfly Bush.