How To Plant, Prune, Fertilize, Water, Grow And Care For Butterfly Bushes (Buddleia)

When planted right and in the right spot, Butterfly Bush are exceptionally easy to grow and care for. 

Here's a breakdown of what you need to know...


Butterfly Bush Cultural Preferences


Soil Preferences

Butterfly Bush aren't too picky about soil type. They prefer a moist but well-drained soil of average fertility. That said, when established they are quite drought tolerant, only requiring supplemental irrigation during prolonged summer dry periods. As with so many other perennial plants, constantly soggy or wet soil can be problematic.


Testing Soil Drainage

If you are uncertain about soil drainage in the area you intend to plant, it's well worth taking the time to test it before planting. 

To test soil drainage, dig a hole 12" wide by 12" deep in the planting area. Fill the hole with water and let it drain. Then, after it drains, fill it with water again, but this time clock how long it takes to drain. In well-drained soil the water level will go down at a rate of about 1 inch an hour. A faster rate, such as in loose, sandy soil, may signal potentially dry site conditions and possibly a need to add some moisture retentive organic matter. A slower rate indicates poor draining soil and is a caution you need to improve drainage, plant in a raised mound or bed, or look for plants that are more tolerant of wet or boggy conditions.



Soil pH

Butterfly Bushes will grow well in a wide range of soil pH between 5.5 to 8.5 on the pH scale. Most average garden soils fall between a pH range of 6.0 to 7.0. 


Testing Soil pH

Soil pH is a measurement of the alkalinity or acidity of soil and is measured on a scale of 1-14, with 7 as the neutral mark. Any measurement below 7 indicates acid soil conditions, and anything above 7 indicates alkaline. 

If you're unsure about the pH of your soil, or whether or not it's suitable for growing a Butterfly Bush, it's a good idea to test the soil pH in the planting area. You can quickly test soil pH with an inexpensive soil pH tester probe. To raise the pH (make more alkaline) you can add pelletized limestone to the soil. To lower the pH (make more acid) you can apply Soil Sulfur, Aluminum Sulfate, or Chelated Iron. Adding organic compost to the soil or using compost as mulch can also help to increase acidity and maintain acid soil conditions. 




Light Preferences

Butterfly Bushes grow and flower best in full to mostly sun. That said, they will tolerate a few hours of light shade or filtered sun during the day. For best flowering, at least 6 hours of direct sunlight is recommended.



How To Plant A Butterfly Bush

Scroll down for container planting instructions and care tips


Step 1

Start by digging your planting hole at least two to three times as wide and no deeper than the root ball of the plant. The wider the hole the better. Place native soil removed from planting hole around the perimeter of the hole, in a wheel barrow, or on a tarp.


Step 2

Depending on the type, fertility and porosity of the soil in the planting area you might need to amend the native soil. When planting in dense clay or other compacted it is beneficial to thoroughly mix in some good organic matter such as composted cow manure, mushroom compost, sand, and/or a good planting mix at a 50/50 ratio with the soil removed from the planting hole. When planting in very sandy, quick-draining soil consider mixing in some top soil, peat moss and/or compost to help retain moisture. When planting in fertile, loamy, well-drained soil there is no need for adding a soil amendment, though some composted organic matter might be beneficial to increase soil acidity.


Step 3

To remove your butterfly bush from the container it was growing grasp the base of the plant with the tips of your fingers and try to gently lift and remove it from its container. If the root ball is stuck in the container it's best to use some snips to cut the container away. After having removed the plant from the container, loosen some feeder roots around the surface of the root ball. If root bound, you can spray the sides and bottom of the root ball with a stream of water from a garden hose. This will help to wash away some soil from the surface of the root ball making it easier to loosen roots.


Step 4

If you are planting in well-drained soil set your Butterfly Bush in the planting hole so that the top edge of the rootball is at or slightly above ground level to allow for settling, as shown in the illustration below. If necessary, add some backfill soil mixture to the bottom of the hole to achieve proper planting height. 

Note:  If the soil is poorly drained (constantly soggy or wet) improve soil drainage or select a different plant species tolerant of wet soils.



Step 5

After setting your plant in the planting hole, use one hand to hold the plant straight and your other hand to begin back-filling your soil mixture around the root ball, tamping as you go to remove air pockets. When you have filled the hole to the halfway point you can soak the soil. Then continue back-filling to the top edge of the root ball. To avoid suffocating your plant, avoid placing any soil on top of the root ball.


Step 6 (Optional)

When planting in a site far from a water source, you can use remaining soil mixture to build a water retaining berm (catch basin/doughnut) about 2 inches high around the outside perimeter of the planting hole, as shown in the illustration above. This basin will help to collect water from rainfall and irrigation often reducing the need for hand-watering. The berm can be removed after a growing season or when the plant has established itself.


Step 7 

Next, deeply water the planting area, including the root ball, to a depth equal to the height of the root ball. To stimulate early root formation and stronger root development, and reduce transplant shock and promote greener, more vigorous plants, you can also water you new butterfly bush with a solution of Root Stimulator.


Step 8

To conserve moisture and to suppress weed growth, spread a 1- to 2-inch layer of shredded or chipped wood mulch or pine straw around the planting area. As the mulch decomposes it will add vital nutrients to the soil that your plants will appreciate. Avoid using freshly chipped or shredded wood for mulch until it has cured in a pile for at least 6 months, a year is better. Avoid placing or piling mulch directly against the base of your plant as this could cause the bark to rot.




How To Plant A Butterfly Bush In A Container


Butterfly Bush growing in pots appreciate a consistently moist but well-drained soil. Constantly soggy soil can and often will cause root rot or other harmful plant diseases. Therefore, I recommend using a quality potting soil or potting mix, or a 50/50 combination thereof and a container with a drainage hole(s) in the bottom.  You can also add 10 to 20 percent perlite or pumice to the soil mixture to help with drainage.

Choose a container that is large enough to allow for 2 to 3 years of growth before shifting up to a larger size container. This might mean your planting pot would be 8-10 inches or more in width than the root ball of your plant. If you intend to grow other plants in the same container garden, up the size. 

Container color will matter as well. Not only will you want to pick a color of container that goes well with the flower and foliage color of your butterfly bush, you'll also want to pick a container that matches the style of your home or other structures and other plants in the surrounding environment. 

Many nursery & garden centers offer a wide variety of containers to choose from. Before heading out to buy a container take pictures of your home and the surrounding environment. Doing so will help you to choose just the right color and style.


Container Planting Instructions


Step 1

Before filling your container with the soil mix, we recommend lining the bottom with shade cloth or a porous landscape fabric. This will keep the drain holes from becoming stopped up with soil. If you intend to use gravel, rocks or other material in the bottom of the the container lay the fabric over it.


Step 2

To remove your butterfly bush from the container it was growing grasp the base of the plant with your thumb and index finger and try to gently lift and remove it from its container. If the root ball is stuck in the container it's best to use some snips to cut the container away. After having removed the plant from the container, loosen some feeder roots around the surface of the root ball. If root bound, you can spray the sides and bottom of the root ball with a stream of water from a garden hose. This will help to wash away some soil from the surface of the root ball making it easier to loosen roots.


Step 3

Pour a small amount of your soil mixture in the bottom of the container. Set the plant in your container and make necessary adjustments by adding or removing some soil so that the top edge of the root ball will sit 1/2 to 1" below the rim of the container.



Step 4

Backfill with your potting soil around root ball, tamping as you go, until the level of potting soil is even with the top edge of root ball.


Step 5

Water thoroughly until water starts to drain from the holes in the bottom of the container. Add more potting mix if settling occurs during watering.


Step 6 (Optional)

Apply a 1/2" layer of wood chips or sphagnum moss to soil surface to help conserve moisture. Alternatively, you can plant low growing or trailing perennial or annual flowers as a soil cover.





How To Grow & Care For Butterfly Bush

Feeding - Watering - Pruning


How To Fertilize A Butterfly Bush


Butterfly Bush are light feeders however will benefit from fertilization. Feed in late winter or early spring with a slow-release shrub & tree type fertilizer or a natural, organic plant food. To avoid stimulating new growth that could be damaged by an early frost, cease fertilization two months prior to the first frost date in your area.


Soil pH

Butterfly Bush grow best in an acid to moderately alkaline soil ranging from 5.5 to 8.5 on the pH scale. Most average garden soils fall between a pH range of 6.0 to 7.0. 


How To Test Soil pH  

Soil pH is a measurement of the alkalinity or acidity of soil and is measured on a scale of 1-14, with 7 as the neutral mark. Any measurement below 7 indicates acid soil conditions, and anything above 7 indicates alkaline. 

If you're unsure about the pH of your soil, or whether or not it's suitable for growing a Butterfly Bush, it's a good idea to test the soil pH in the planting area. You can quickly test soil pH with an inexpensive soil pH tester probe. To raise the pH (make more alkaline) you can add pelletized limestone to the soil. To lower the pH (make more acid) you can apply Soil Sulfur, Aluminum Sulfate, or Chelated Iron. Adding organic compost to the soil or using compost as mulch can also help to increase acidity and maintain acid soil conditions.





How To Water A Butterfly Bush

When established, Butterfly Bush are quite drought tolerant. That said, they will require water to become established. Constantly soggy or wet soil can be problematic.


At Planting Time 

Immediately after planting deep soak the soil in the planting area, including the rootball, to a depth equal to the height of the root ball. For an extra boost, to stimulate early root formation and stronger root development, and reduce transplant shock and promote greener, more vigorous plants, you can also water you new butterfly bush with a solution of Root Stimulator.


During The First Active Growth Season

In average garden soil you should not have to water your newly planted Butterfly Bush every day. More often than not, this causes soggy soil conditions, which can lead to root rot and other plant diseases. In the absence of sufficient rainfall, water only as needed to keep the root ball and surrounding soil damp to moist. 

Keep in mind that deep soaking less frequently is much better than splashing just a little water on the plants every day. Butterfly bushes planted during the winter dormant season, when plants are not actively growing and evaporation is much slower, will require much less water. So, be extra careful not to overwater during winter!


Thereafter

When established, Butterfly Bush are quite drought tolerant. Only during prolonged periods of summer drought will plants require supplemental irrigation. If you see leaves wilting during a summer drought this could be an indicator that your plants could use a good deep soaking.


Tip:  When watering with an automated irrigation system it's best to set your timer to water during the early morning hours and not in the late evening or at night, which can lead to the onset of fungus and other foliar diseases. During the first few weeks after planting, check soil moisture often and adjust irrigation time if necessary to keep the soil moist, not wet. 



How To Prune a Butterfly Bush

Butterfly Bush do not require pruning, however respond well to and benefit from it. 


Deadheading

No, this has nothing to do with following a rock band around on their nationwide tour:-) Deadheading is a simple task which takes only a few minutes. 

If you've never dead-headed before here's how to go about it: 

First, keep a watchful eye on your plants, paying close attention to blooms that are past their best. Once a flower has started to fade remove it from the plant with a quick snip from your bypass hand pruners. When doing this try to remove just the spent flower leaving the new buds beneath intact.


Annual Pruning

Many varieties of butterfly bush can become quite large (up to 12' tall). You can hard-prune your Butterfly Bush in late winter or early spring, when new growth begins to emerge. At this time, remove all dead plant parts. Living branches can then be pruned to the same height.  In Northern zones, where butterfly bush may die back to the ground, when new growth begins to emerge you can prune plants to just 4 to 6 inches above the ground.

Note:  In regions that receive a lot of snow and severe cold temperatures during the winter months, it is highly recommended to wait until spring arrives to prune butterfly bush. Leave the canes to trap and hold a layer of insulating snow around the base of the plant throughout the coldest parts of the winter. Then, when snow has left for the season you can prune.

  




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