Propagating Butterfly Bushes

Butterfly bushes are attractive flowering shrubs that grow in zones 5 through 10. The purple-hued flowers grow in cone-shaped clusters and put on a lovely display from mid-summer through fall. Butterfly bushes are a must-have in a butterfly garden or pollinator-friendly landscape. These plants are easy to maintain, especially once established, and faithfully return yearly. Butterfly bushes are easy to propagate, so you can use them throughout your space or share them with friends and family.

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Photo by Jerry Norbury, unedited, Flickr, copyright CC BY-ND 2.0 DEED

Methods To Propagate Butterfly Bush

Propagate butterfly bushes through division or stem cuttings. Both methods of propagation are easy, so you can choose the method you prefer or that works best for your situation. Propagating through division is best when you have a large, overgrown plant. Separating one large butterfly bush into several smaller plants rejuvenates the plant and allows each new plant to thrive.

Creating new plants through stem cuttings from an existing plant is slightly more involved but still an easy process. Use stem cuttings if you have an established plant that is not unwieldy or overgrown. The cuttings should form roots in 3-6 weeks.

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Photo by Leonora (Ellie) Enking, cropped, Flickr, Copyright CC BY-SA 2.0 DEED

What You Need To Propagate Butterfly Bush

To divide a butterfly bush, use a sharp garden spade to separate part of the plant, or dig up the entire rootball and manually untangle the roots. You can trim the roots as needed using pruning shears. Replant each new plant in rich, well-drained soil. 

To take cuttings, you’ll need clean, sharp pruning shears. Root the cuttings in a container filled with rich, well-draining soil. Up to three cuttings can be rooted in a 6-inch pot. Rooting hormone is helpful but not mandatory for propagating butterfly bush.

Best Time To Propagate Butterfly Bush

Butterfly bush shrubs can be divided in the spring or fall. Spring is a good time to divide the plant if you live in the colder reaches of its growing range, so the shrub will have the entire growing season to acclimate. 

Butterfly bush cuttings should be taken in the spring or summer to be rooted and planted before winter. It will take several weeks for roots to grow, and the young plant needs time to settle in before colder temperatures arrive. Stem cuttings taken later in the season will need to spend the winter indoors in cold climates.

Steps To Propagate Butterfly Bush

Step 1 - Use sharp shears to take a branch tip cutting that measures several inches long. Make an angled cut to best support rooting.

Step 2 - Remove the lower leaves.

Step 3 - Fill a container with a moist, well-drained potting mix.

Step 4 - Plant the cutting in the prepared pot.

Step 5 - Move the container to a spot that receives partial shade and keep the soil moist.

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Photo by Jerry Norbury, cropped, Flickr, copyright CC BY-ND 2.0 DEED

Caring For Young Butterfly Bush Stem Cuttings

Help a butterfly bush set roots by keeping the soil damp. The cutting needs a moist environment to grow roots, but too much dampness will rot the stem before any roots can grow. Water the cutting when the top layer of the potting mix is dry to the touch. Butterfly bush cuttings also need partial shade or limited sunlight to set roots. Too much sunlight will dry out the soil and the cutting. Keep the cutting in a warm area. Extreme temperatures can impact whether roots develop.

It will take several weeks for roots to appear and then a few more weeks for the root system to become established. Once the root system has filled in and can support the plant, the butterfly bush will begin to grow. When several inches of new growth appear, it is time to transplant the new butterfly bush into a permanent container or a spot in your landscape.

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Author Alison Cotsonas - Published 12-11-2023