This plant was sold to me by Plant Paradise a very reliable nursery. It was sold with the tag saying it was Grand Cascade Butterfly bush. I watched it grow and compared to the 2 others I have and it did not look quite the same. It is only blooming now whereas the other two have bloomed for about a month. I sent a photo to PP and was told it was not a Buddleia. I tried looking on Google Images and my niece on Picture This. The best we got was the Chaste Plant (tree) -Vitex agnus-castus. But it seems to have leaves grouped in 5 which this does not. It is in the sunniest part of my garden beside a buddleia and behind a hydrangea and Russian sage. The plant is now 3 ft W x 4 ft H. In the picture you can see the other buddleia in the background.
This is very challenging! I agree with you that it’s not a Chaste tree (Vitex agnus-castus). It’s hard to tell much from your photo, but I reached out to other Master Gardeners on our team for assistance in identification. Some responded that the bush is indeed a Buddleia, but it is not clear what species it might be – not the Buddleia ‘Grand Cascade’ that you believed you were purchasing. One colleague suggested Buddleia salviifolia, or sage leaf butterfly bush – but this is hardy only in warmer regions, and grows naturally in Africa – so would not overwinter well in the GTA. There are many varieties of Buddleia. Another suggestion was Itea Virginia, or Virginia sweetspire – although the leaves on this plant look quite different from those in your photo. And the individual flowers of the sweetspire are distinct from those of the Buddleia.
I suggest taking comparative photos of your unidentified plant and the Buddleia in the background – take photos of the leaves, stems, flowers and the bushes themselves – and see how they differ (or are similar). Your local nursery, or Plant Paradise, may be able to identify it from clearer photos. Plant Paradise may have a list of Buddleia varieties it had on hand when you purchased your plants.
You seem to enjoy this shrub, which appears to fit into your garden space nicely. Good luck finding out what it really is! We’d love to hear back if you do find an answer.
You may be interested to know that the butterfly bush is considered invasive an many areas, and may soon be a concern in Ontario. See In our Nature Native Alternatives to Invasive Plants for suggestions about non-invasive plants that might look great in your garden.