(1) Should I let annual fleabane in my garden be? (2) Confirm that the eastern salt marsh aster is not native to Ontario



I’ve noticed the at annual fleabane is growing in my garden and I am conflicted about what I should do about it. I am trying to grow a native garden and I’m worried that since the annual fleabane is an aggressive spreader it would outcompete my other native plants. Should I weed it out? Another question I have is about the eastern salt marsh aster, it seems it is native to parts of Canada but not Ontario, is that correct?

Thank you for all of your help!


Fleabane:  The annual fleabane, Erigeron annuus, flowers from June to the late fall, and the flowers’ nectar and pollen are attractive to pollinators as well as other insects.  So if you feel the plant adds interest to your garden, consider keeping it, perhaps in one or two small areas.  Just keep it under control with hand-weeding.  I enjoy this plant in my garden, especially when it springs up in surprising new spots.


Eastern salt marsh aster: Short answer – you are correct!  The longer answer is more interesting and not so simple.

The eastern annual saltmarsh aster, Symphyotrichum subulatum (formerly Aster subulatus) has naturalized in southwestern Ontario, but is adventive in other locations.  A “naturalized” plant is a non-native plant that does not require human intervention to reproduce/maintain itself in its non-native environment.  An “adventive” plant is one that has become established in an area other than its origin, with the help of humans.  If an adventive plant becomes self-sustaining in its new environment, it is then called naturalized.


All the best in growing your native garden!  Take a look at our Ask a Master Gardener website for ideas – just enter the search term “native” and you’ll find many helpful documents and responses to prior questions.

May 30 2022