How to Plant, Grow, and Care For Butterfly Bushes
Are you thinking of adding some butterfly bush to your garden this season? Butterfly bush is a beautiful purple blooming perennial plant, and can function well in many different hardiness zones. It's also famous for attracting plenty of butterflies! In this article, gardening expert Jill Drago walks through everything you need to know about the butterfly bush and its care.
Butterfly bushes are lovely flowering shrubs that are well loved for their perfect vase shape, and their bright panicle flowers that bloom most of the summer. These beautifully blooming shrubs come in just about every color, making it easy to add them to garden spaces. When the flowers are not in bloom, their silver foliage creates a soft backdrop for the rest of the landscape.
If you are in the market for an easy-to-care-for plant with a large wow factor, the butterfly bush is a great choice. These shrubs will grow in most conditions including city dwellings, dealing with pollution and high traffic very well. These shrubs are sun lovers, and will do best with six hours or more of sunlight per day.
Let’s learn a bit more about this interesting plant. You’ll learn when to plant it, where to plant it, what to plant it with, and everything you need to know about Buddleia davidii and its care. Let’s dig in!
Butterfly Bush Plant Overview
Plant Type Perennial, Flowering Shrub
Pests Spider Mites, Nematodes
Exposure Full Sun
Diseases Root Rot
Maturity Date 1-2 years
Growth Rate Fast
Soil Type Well Draining
Native Area Asia
Plant Spacing 5-10 feet apart, variety dependant
Plant With Full sun perennials and annuals
Planting Depth Container depth
Watering Requirements Low to Moderate
Don’t Plant With N/A
Height 2-12 feet tall, variety dependant
About Butterfly Bush
The butterfly bush is a member of the Scrophulariaceae family. Other members of this family include snapdragons and nemesia. This family is made up of perennials as well as other shrubs. One way to identify this family is by taking a look at the flowers. There will often be many flowers arranged radially around a stem.
Their flowers are fragrant and can reach up to one foot in length. The length of the flowers will differ from variety to variety. The flowers will bloom on new wood, if you wish to have a strong bloom it is strongly suggested that you prune in the spring.
The butterfly bush has roots in central China. As it made its way to the Americas it evolved into more than 140 species. Our most popular species in North America is Buddleia davidii.
The plant was brought to Europe by botanist Addam Buddle. This is where the plant got its botanical name: Buddleia davidii.
This shrub has always been known to be a tough plant that will grow just about anywhere. After World War I ended, it was planted around the heavily bombed areas of Europe to encourage the growth of new vegetation.
Butterfly bush easily self-sows, and has been labeled as an invasive plant in some areas. Invasive plants, have the ability to spread easily, typically through seeds, and are tough enough plants to take hold pretty much anywhere.
The aggressive growth habit of invasive plants can cause issues amongst native plants, by crowding them out. When native plants become limited the native wildlife may struggle to find food to eat. It is because of these reasons that the butterfly bush has been hybridized and there are countless seedless, non-invasive butterfly bush varieties available.
The nectar of the flowers is very attractive to adult butterflies, however, the caterpillars do not munch on the leaves of this shrub. This makes it difficult for the butterfly to have a full life cycle in this plant.
The aggressive nature of the plant can crowd out other wild and native flowers that benefit the butterfly, causing a bit more of an issue with the butterfly population.
When it comes to propagation, there are two main methods that are commonly used by gardeners: by cutting or by seed. Both of these methods are fairly easy and can be done by even beginner gardeners. Let’s take a deeper look at each propagation method.
Butterfly bush propagates easily from softwood cuttings taken in May or June. Simply take a cutting with a few leaves on it, dip it in the rooting hormone, and stick the cutting into a sterile planting medium.
Once the cutting has formed roots you can move it into an area that has growing conditions that will benefit the adult plant. Do not mist the plant at this stage, too much moisture will damage the plant and could cause it to rot.
At this point, it is a good idea to offer the cutting some water-soluble fertilizer. You should notice buds forming and the lengthening of the cutting within about a month.
As already mentioned, these shrubs produce plenty of seeds and they germinate and grow easily in gardens. Unless of course, you purchased a seedless variety.
Collect your seeds, and simply plant them either in your garden and let nature take its course, or plant them inside in a more controlled growing environment. Use a sterile growing medium if it is available to you. Water sparingly until the seed germinates, keeping the soil moist but not too wet.
If you are growing your seedlings indoors, you can move them outside once you have a few sets of leaves and when the temperatures are warm. If you sowed the seeds outdoors, you will notice germination within a week and your new plant will be fully mature by the end of its first growing season.
Butterfly bushes are not too picky when it comes to their growing conditions, as long as they are receiving full sun and their feet are not too wet. Choose a site in your yard that gets six or more hours of sun per day, and that has well-draining soil.
Once you have chosen your plant site, remove the plant from its nursery pot and gently disturb the roots. Dig a hole in the ground that is twice as wide and as deep as the root ball of the plant.
Place the butterfly bush in the hole, and backfill with garden soil. Press the soil firmly around the plant to get rid of any potential air pockets which could later cause the plant to sink or could hold excess water which could damage the roots.
Water the fresh transplant low and slowly. Allow the soil to absorb the water without any puddling. Water weekly or more frequently as needed until the shrub has established itself in your garden.
How to Grow
Living in the right hardiness zone and planting at the right time are the foundation of growing butterfly bush. In these conditions, it is a fairly easy shrub to grow. Read up on the basic needs of these plants so you can know just what to do to help them thrive.
This shrub thrives in full sun. It prefers anywhere from six hours or more of sunlight. This is true even in warmer climates. If your Buddleia davidii is getting too much shade it will become leggy and unattractive.
There are many varieties that will do just fine in partial shade, or four or more hours of sunlight. just keep in mind that the flowers may not bloom as large and full in these conditions. Plant them with other full sun perennials such as coneflower or black-eyed Susans.
Butterfly bush likes a moist environment, but not one that is soggy. When its first planted, water the shrub about once a week until it establishes itself. Once the roots have taken hold, the plant will be mostly drought tolerant.
If the leaves are wilted, do not rush to water your plant. Check out the soil first. Wilted leaves could be a sign of both dry plants and overwatered plants.
Other signs that you could be watering too frequently will be weaker or leggy stems and fewer flowers. If you use an irrigation system, be sure to check the amount of water your shrubs are getting by using a rain gauge. You may need to adjust.
Plants living in containers may need to be watered a bit more frequently. The limited soil in the container will dry out quicker and the roots will feel the full effect much quicker than they would if they were growing in the ground.
Plant in well-draining soil. Make sure it retains moisture but does not become soggy. Excess moisture in your soil can lead to root rot.
Butterfly bushes like a neutral soil pH of anywhere between 6 and 7. If you are unsure of your soil pH, run out and grab a quick pH test from your local garden center. You can always save this step, and test your soil if your plant doesn’t quite seem to be thriving.
Adding compost to your soil is a good way to balance your soil without adding any chemicals while giving your plants the benefit of added nutrients. This step should be completed at the time of planting.
Climate and Temperature
Butterfly bush is hardy and will perform well in zones 5-9. In zone 5, be prepared for the shrub to die back to the ground in the winter, and reemerge come springtime. There are some hybrid varieties that might be less tolerant of the cold.
In warmer zones, you can let Buddleia davidii over winter and then prune it back in the spring. This allows you to experience a rejuvenated shrub with healthy new growth and prolific blooming during the growing season.
If you have planted in rich, fertile soil, there will likely be no reason or need to add extra fertilizer. There are many ways to check the different nutrients in the soil to see just how fertile it is. The best way is to send it to a lab for testing.
If the soil does need to be fertilized, Buddleia davidii only require an all-purpose fertilizer, or a 10-10-10. Adding compost to your gardens before planting also helps give the plants what they need in terms of nutrients while improving the overall structure of the soil.
This perennial plant is known to be low-maintenance. However, this doesn’t mean no maintenance at all. They do require some upkeep other than the typical basic needs of plants. Take the time to learn about these simple needs to ensure the healthiest and most bountiful shrubs.
Deadheading is an important step in maintaining your butterfly bush. Remove the spent flowers as soon as you notice them by snipping them right off of the stem. This plant will reproduce by seed quite easily, and if you let the spent blooms linger for too long, then you will have a lot of new baby shrubs on your hands.
If you have purchased a seedless variety, you will not need to deadhead. In many cases, the seedless varieties will continue to bloom all season long.
Adding mulch around your perennial gardens is a great way to keep the roots of the plant safe from weather extremes, either warm or cold. It also helps to keep the plant from drying out.
Add new mulch every season to keep your garden fresh. Pull it back an inch or two from the trunk of the plant to help prevent any rot of the trunk or roots. There are many different materials that can be used as organic mulch from straw, tree bark, or leaves.
Butterfly bushes are aggressive growers, and can greatly benefit from pruning. If you are trying to keep your plant from becoming too unruly, cut the shrubs down to ground level each spring once you see some new green growth appear. This is called hard pruning and it will help to invigorate the plants and promote blooms.
If you are happy with the size of your plant, you can just do a tip pruning in the spring to shape up your shrub. Keep in mind though, that if you don’t prune regularly, the blossoms only emerge on new wood, so the flowers will only be at the top of the plant.
Pruning in the fall can cause damage to the plant. The new wounds from pruning may not have time to heal before the cold of the winter sets in.
There are a number of different varieties to consider growing in your garden. They come in different colors, ranging from vivid pink to soft purple. You will also find them in many sizes that can be used as a border to the main event in a garden bed. Whatever variety you choose, butterflies will be sure to flock to your garden!
‘Flutterby Grande Peach Cobbler’
The flutterby series is completely made up of seedless noninvasive varieties. The peach cobbler variety is a larger shrub that dons peach-colored flowers, but can sometimes be more lavender to pink with an orange center.
This variety grows upright in nature and will grow from 4-6 feet. Plant ‘Peach Cobbler’ with your purple perennials for a vibrant contrasting effect in your garden. This variety can live for about 20 years when in the right conditions.
This variety of butterfly bush has beautiful multi-colored flowers. Each panicle flower of this shrub will have shades of purple, peach, pink, and orange. Growing up to 5 feet tall, this variety would make a great choice for a statement shrub all on its own, or planted as a large hedge for privacy.
There is a scent that comes from this variety. The fragrance and showy flowers are what attract pollinators, especially hummingbirds and butterflies. They are an excellent source of nectar for such insects and birds.
‘Ice chip’ is a pretty, dwarf shrub for smaller spaces. This shrub blooms with crisp, pure white flowers. ‘Ice Chip’ is a non-invasive variety that will only grow between 2 and 2.5 feet. The foliage on this variety is a soft silvery green, which makes the white flowers pop even more!
‘Ice Chip’ has a spreading growth habit. This paired with the compound size makes it a great plant for a ground cover in your sunny gardens. The continuous blooms mean there is no need to deadhead.
This butterfly bush is a beautiful small variety, growing from 2 to 5 feet. The flowers are a deep purple with pink centers. The foliage is a soft green. ‘Purple Emperor’ would be a great addition to a perennial garden.
‘Purple Emporer’ is a good choice for outdoor gardens as a complimentary shrub. It will also grow well in containers, particularly as a thriller due to its upright growth habit. However, if growing in a container, be sure to adjust the watering needs.
The flowers on ‘Hot Raspberry’ are perfect for an area you want some bright color. The blooms from this shrub are bright pink and fragrant. This variety of Buddleia will grow to five feet tall, and five feet wide. It is a fast grower, so you will see it reach this size in no time.
The foliage is a silvery grayish-green color, which contrasts beautifully against the vivid pink flowers. The deep magenta blooms should last through the summer months and into autumn. It is an excellent choice for a border plant or in perennial flower beds.
One of the best things about growing butterfly bush is that they do not come with too many problems. However, there are still a few pests and diseases that can pop up. Common problems include nematodes, spider mites, and root rot.
Nematodes are microscopic worms that live in the soil and feed on the roots of plants. Lucky for us butterfly bush growers, nematodes love to nibble on their roots. Typically these worms do not leave the soil, but they have been known to move up to the leaves. The females will lay their eggs around the plant roots and the population will skyrocket.
If you are curious if nematodes might be negatively affecting your butterfly bush you can dig around in the dirt and examine the roots. Usually, the roots will be discolored and shorter if they are being nibbled by nematodes.
Controlling nematodes can be difficult. There are liquid nematode controls available at garden centers that can be helpful. The best ways to keep your plant healthy and nematode-free are to keep your garden clean and water the shrub correctly.
Spider mites love to make themselves at home on stressed-out plants. This usually means plants that are suffering from drought stress. Now, this can get tricky since we have been talking about how low-maintenance butterfly bushes are and how they can withstand drought, right?
Spotting these mites can be a bit tricky. You likely won’t even see the mites, but you will see the webbing they create around the plant’s leaves and stems. If you notice this webbing, take a closer look at the plant for very small insects that resemble spiders.
The best way to control mites is to keep your plant watered properly. They like to be kept moist in well-draining soil. If you do notice mites on your plants, spray them down with your hose to knock them off. Insecticidal soap and horticultural oil can also be useful against mites.
Butterfly bushes, like most plants, are susceptible to root rot. This fungal disease commonly occurs in soils that are wet and do not drain well.
You may notice your plant is struggling with root rot if you notice the yellowing of leaves, smaller blossoms, and stems or branches rotting within the plant. Unseen symptoms of root rot are the actual rotting of the roots beneath the soil.
Root rot is difficult to tackle because it has usually been going on for a while before you notice it above ground. The best way to treat root rot is actually just to prevent it. Plant in well-draining soil and make sure that you are not watering too frequently.
With the varying sizes of the plant, there are many ways it can be utilized in your garden. The name of this shrub can not be ignored. This is one of the best plants you can grow in your garden that will attract butterflies. If it is your goal to attract more butterflies and other pollinators, plant some coneflower, or milkweed nearby!
Plant dwarf, or even full-size, varieties in containers! The shape of the butterfly bush lends itself perfectly to being a solo plant in a large container. Plant spillers, such as petunias, underneath for a more dramatic look.
Use a large variety as a specimen plant in your gardens or plant them in a mass planting for a beautiful and wildlife-friendly hedge.
The flowers can also be used as cut flowers. The blossoms will begin to fade after a day or two, so be sure to cut them just before you want to use them. Pair them with hosta leaves or hydrangea blossoms for an impactful bouquet or vase arrangement.
Frequently Asked Questions
Is butterfly bush invasive?
The short answer to this is yes. Many of the early varieties of butterfly bush are considered invasive due to the amount of seeds each plant produces, and the high success rate of those seeds germinating in your garden.
There are a few things you can do to decrease the likelihood of having your garden overrun. The first is to stay on top of deadheading. If you remove the spent flowers, they will never have the opportunity to produce seed.
The second is purchasing a seedless variety. The seedless varieties are a response to the invasiveness of the plant. They will not produce seeds as the original species or varieties will.
Butterfly bush is invasive where I live. What can I plant instead?
If you are desiring the beauty of a butterfly bush in your garden, but you know that it is invasive in your area, there are a few things you could plant in place of these pretty flowering shrubs. Before we move onto other plants, it should be noted that there are seedless varieties of butterfly bush that are readily available. These varieties are not invasive.
If you are looking for another option altogether, give one of these native plants a try:
- Summersweet, Clethra alnifolia
- Virginia sweetspire, Itea virginica
- Anise hyssop, Agastache foeniculum
- Joe Pye Weed, Eutrochium purpureum
- Butterfly Weed, Asclepias tuberosa
Why isn’t my butterfly bush blooming?
First, check your planting site. Is your shrub getting enough sun? This shrub needs six hours or more per day to grow optimally. How much water is your plant getting? These flowering shrubs need about ½ inch of water per week. Any less, and your plant will withhold blooms to make it through a drought period. Too much more water, or plants living in soil that does not drain well and you will be headed towards root rot.
Check your planting practices. Butterfly bushes do not like to be planted too deeply. When you plant you should keep the plant buried as deeply as it was in its nursery pot.
They are hardy in zones 5-9, and they need mild summer temperatures. If the temperatures are too cool, your plant may skip a bloom period. Be patient, butterfly bushes are some of the later plants to come back to life after the winter time. Sometimes they wait until June to wake up from their hibernation.
Can I grow them in clay soil?
Butterfly bushes require really well draining soil in order to prevent any root rot, and to grow to the best of their ability.
If you live in an area where there is clay soil, the goal will be to create a slope once you are done planting. Typically you want the crown of the plant to be level with the soil line, but in this case you will want it to be above the soil line by an inch or two.
This means digging a more shallow hole! Backfill your soil as usual, making sure all of the roots are securely covered with soil. This slope you have created will encourage water to run away from the plant instead of sitting around the roots and puddling.
Another way to help them thrive in clay soil is to lay off of the mulch. If they are hidden in the back of the bed, skip mulching around the shrub all together.
Despite their reputation for being quite invasive, I urge you to try adding some butterfly bushes to your gardens. There are plenty of seedless varieties available, with more coming out each year. Whether you pick a dwarf or standard size the beautiful panicle flowers add a real wow factor to your yard.
Each year when the bright colors start to bloom in my garden and my family’s garden, it’s a sure sign of summer that sets our gardens aflame with colorful blossoms and their butterfly friends!