I was organizing my seeds for sowing and came across you article https://torontobotanicalgarden.ca/get-gardening/annas-pick-balloon-flower/ and an article https://pegplant.com/2017/08/01/invasive-balloon-flower-takes-over-the-garden/ that suggested Balloon Flower is invasive. I did not find it listed as an invasive species in Ontario https://www.ontarioinvasiveplants.ca/invasive-plants/species/. I wonder if it should be encouraged.
Can someone comment about the invasive status and if I should be concerned sowing these seeds?
Thank you for your time,
Lisa Fedele
Thank you for your query about whether Balloon Flowers (Platycodon grandiflorus) are invasive.
Please note that we are an independent non-profit organization and not part of the Toronto Botanical Garden (although we do partner with them sometimes for various events). The post you refer to (Anna’s Pick – Balloon Flower) was not written by us.
Balloon flowers belong to the plant family Campanulaceae – a large family that also includes Bellflowers (Campanulas, and specifically the upright bellflower (Campanula persicifolia) and the invasive creeping bellflower (Campanula rapunculoides).
I cannot find anything to suggest that Balloon Flowers (Platycodon grandiflorus) and the upright Bellflower (Campanula persicifolia) are invasive or that they OVERLY self-seed in the Greater Toronto Area, which is mostly Zone 6, although they may self-seed somewhat in some gardens. I’ve reviewed the other post you referred to in your question (https://pegplant.com/2017/08/01/invasive-balloon-flower-takes-over-the-garden/). This post on Platycodon grandiflorus was written by a Virginia gardener in USDA Zone 7 (equivalent to Canadian Zone 8). Virginia has a different climate and growing conditions than we do in Toronto.
Having said that, our Southern Ontario climate is changing and warming up and when a plant that is non-native to North America is reported to be invasive in the US, it is wise to pay at least some attention to those reports. I note that in the comments to the Virginian gardener’s post, a gardener in Indiana in USDA Zone 5 (the equivalent of our Zone 6) also reported it to be invasive and very difficult to dig up. The posts by other commenters (who did not identify their zone or state) were mixed – some reported prolific self-seeding and others said it was not a problem. I live in an area of Toronto that is considered to be Zone 7a, so I am especially interested in what is going on south of the border, particularly in northeastern US.
I suggest that if you choose to sow your Balloon Flower seeds and grow them in your garden, you keep a close eye on them. If you find they are starting to be a problem with self-seeding, you should pull up your plants or deadhead them before they go to seed.
Or you may decide to grow a native plant instead (you could do an internet search for plants suitable to your conditions or buy or borrow books written by Lorraine Johnson, “100 Easy-to-Grow Native Plants for Canadian Gardens” and (with co-author Sheila Colla) “A Garden for the Rusty-Patched Bumblebee: Creating Habitat for Native Pollinators”). The North American Native Plant Society (NANPS) has plant sales of native plants every summer – you can get on their mailing list to be notified of the location of the sales and you can order plants online and then arrange to pick them up at one of the sale locations.
Finally, as you have noted, a good way to check whether a plant is invasive in Southern Ontario is to check the Ontario Invasive Plant Council’s website for their list of invasive plants and their publication “Grow Me Instead” which provides more expansive information on invasive plants and alternative plants to grow.
Note that some native plants can be aggressive in their own right – either through self-sowing or expansion by rhizomes or both. Not all are suitable for small gardens or limited spaces, so it is wise to do research before you plant anything (native or non-native) to make sure that you are happy with the results and able to take care of the garden without excessive work.
I’ve included a some links below.
Invasive Species (Ontario Invasive Plant Council)
Grow Me Instead (Southern Ontario) guide, 3rd Edition (Ontario Invasive Plant Council)
The Best Native Plants for Toronto Gardens (toronto.ca)
North American Native Plant Society (NANPS)