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Did you know that it’s actually pretty simple to grow Butterfly Bush from seed? Although the seeds are very tiny, they’re not difficult to collect. Don’t have a plant to collect seeds from? You can actually find a good selection of Butterfly Bush seeds on Amazon.
In some areas the Butterfly Bush (Buddleia davidii) is considered invasive and grows like weeds along roadsides. However, you’ll likely find at least one in every butterfly gardener’s landscape. Butterfly bush is known to readily self-seed but in a mulched bed the tiny seedlings will have a difficult time reaching daylight. As such propagating them in containers may be a better option. If you’re looking to increase the amount of Butterfly Bushes in your garden on the cheap then propagating from seed is the way to go!
Collecting Butterfly Bush Seed
The seeds of the Butterfly Bush can be collected throughout the year as the blooms wither. Spent blooms will turn from green to brown and contain dozens of little seed pods. Inside each of the pods will be several of the tiny seeds. When I say they’re tiny I mean they are really tiny. To the naked eye it’s difficult to decipher seed from chaff.
Gathering Seeds at the Right Time
Timing is important. You want to collect the spent blooms before the seed pods completely dry out but before they crack open. Equally important, be sure the entire bloom has turned brown to ensure the seeds are mature and viable. After gathering the spent blooms bring them indoors and place them on a paper plate in an area free of drafts to let them dry out completely. Once fully dry the little seed pods will be spread open resembling little brown flowers (pictured above). At this point you can just hold the dried bloom over the paper plate and tap it gently. The seeds will easily fall out.
If the seed pods have already split open you can also attempt to collect seeds without removing the spent bloom. The seeds fall out really easily so attempting to remove the blooms once the pods are already open would likely result in losing all the seeds. At this point just hold a container or paper plate under the dried flower and give it a tap. Be sure and do this on a windless day.
By using some form of magnification, I used my phone camera, you can see that the seeds of the Butterfly Bush are tapered on both sides. The dark spot in the middle is the embryo of the seed. You’d be surprised how many seeds you can get from just one spent bloom.
Growing Butterfly Bush from Seed
Ok you’ve done the hard part, now let’s grow butterfly bush from seed. I recommend starting with small container or cell packs to germinate the seeds. Fill the container of choice with a good, sterile, seed starting mix. It’s best to moisten the soil before sowing the seed.
Assuming you harvested the seeds at the proper time they should be mature and viable. This should yield excellent germination rates. Just put a few of the butterfly bush seeds on top of the soil of each cell or container. By placing just a few seeds you’ll reduce the need to thin out the seedlings later. Don’t bury the seeds, you only need to lightly press them onto the top of the soil. To ensure the seeds don’t dry out you should place the containers under a humidity dome or cover them with plastic. Butterfly Bush seeds need light to germinate which can be provided from a grow light or in a windowsill with indirect sunlight.
Butterfly Bush Germination
My experience with growing Butterfly Bush from seed is that they typically germinate within about a week if kept at least 70F.
As you can imagine, since the seeds are tiny the initial sprouts will be very tiny as well. Once germination occurs the seedlings gain size fairly rapidly. You may have multiple seeds that germinate in each container. After about two weeks you can thin them down to one seedling per cell or container. It’s best to just cut the extra seedling off at soil level with scissors so as not to disturb the roots of the desired seedling.
Seedlings can be transplanted to 3″ containers after about 2-4 weeks. By this time, they should have multiple sets of true leaves. Once moved into the larger container you can fertilize if you chose. Just be sure and start out with about half strength fertilizer.
Your Butterfly Bush seedlings should be ready to transplant into the garden once you see some roots starting to grow out the bottom of the 3″ container.
If you start to grow butterfly bush from seed early enough before spring, they will flower the same year. Most varieties are perennial down to Zone 5.