Symphyotrichum prenanthoides

Crooked-stem aster

Named for its zig-zagging stem, the perennial crooked-stem aster is listed as Special Concern in Canada under the Species at Risk Act. In Canada, it is found only in a small number of populations in southwestern Ontario, within a small area of Carolinian forest.

Photo credit: Emma Neigel


The situation

Plant diversity is being lost at an accelerated rate

At the northern end of its range which extends into Canada, the crooked-stem aster (Symphyotrichum prenanthoides) — like many other species in the Carolinian forest — has historically been threatened by habitat loss. 22 populations are thought to exist. Current threats include competition with invasive species like garlic mustard (Alliaria petiolata) and habitat degradation resulting from pressures of high human density.

Photo Credit: Jenny McCune

Our work

The Wilder Institute has over 20 years of experience working and advising on conservation translocation projects around the world. With this experience, we are providing guidance and training to our partners that will contribute to the success of this initiative.

Plant Propagation & Translocation

This research aims to increase the number and size of populations of at-risk Canadian plant species on protected lands. To accomplish this, researchers will be using the conservation tool of translocation to create new populations of crooked-stem aster in suitable habitats within the species’ historical range.

Our partners at the University of Lethbridge are using computer modelling and Species Distribution Model (SDMs) to rank habitat suitability as low, medium, and high and will be exploring how well these SDMs can predict the success of these translocations.

Researchers are also investigating the effect of other factors on the success on the translocation of the crooked-stem aster. Some factors to be tested include the effect of propagation method (i.e. using seed, immature or mature plants) and the effect of protected and unprotected plantings. Providing a protective structure over a translocated or recently seeded plant can help to protect from herbivory from animals such as white-tailed deer and mice.

They will be testing the effects of environmental factors of the sites such as sun exposure, soil moisture, and canopy cover. Finally, they will also be looking at the effects of competition by removing all other species in a plot and imitating mowing in adjacent plots. In addition to this research, the team will be plating some plants back into wild sites as a reciprocal plating or test control.

This research will also increase our knowledge of the life history and population demographics of some of Canada’s plant species at risk, including:

  • Drooping trillium (Trillium flexipes)
  • Green dragon (Arisaema dracontium) 
  • Green violet (Hybanthus concolor)
  • American gromwell (Lithospermum latifolium) 
  • Virginia bluebells (Mertensia virginica) 
  • Goldenseal (Hydrastis canadensis
  • Spotted wintergreen(Chimaphila maculata)

Our conservation impact

The knowledge gained from this research has the potential to be used in plant translocations across Canada and beyond. It will inform recovery efforts for at-risk plant species in Canada and increase the knowledge and capacity to use translocations as a recovery tool for rare plant species in the future.


The Quiet Green Creatures – A Video by The University of Lethbridge

Did you know?

The crooked-stem aster forms clumps of stems all coming from the same underground stem, or rhizome. All the flowers in this clump come from the same individual plant, making them genetically identical or clones. Successful pollination occurs when pollen is transferred, usually by insects like bees and butterflies, between these clones.

Photo credit: Emma Neigel


We are grateful for the collaboration and the opportunity to support the following partners on this important project.

Join the movement

Incredible successes can be achieved when we work together.

With your support, we can help create a wilder world for these plant species-at-risk. Join our donor community and take action for wildlife and wild places today!

Photo credit left and right: Jenny McCune
How you can help