Western Spiderwort

Western Spiderwort

Tradescantia occidentalis

Status in Alberta:

Endangered (At Risk)


Active (drifting) sand dunes with sparse vegetation.


Western Spiderwort gets its’ name from the stringy threads that form when the leaves and stems are injured. The sticky substance secreted by the plant dries into cobweb-like material. The long grass-like leaves make the whole plant look a bit spider-like too!


Western spiderwort grows on active sand dunes in southeastern Alberta.

Dune Dwellers

There is only one known location where Spiderwort exists in Alberta. The plants grow in a small area of active sand dunes in southeastern Alberta. Sand dunes are restricted to only a few areas in southern Alberta and many have become stabilized over the past 70 years.


Purple Blooms

Spiderwort flowers range from pink to violet and are arranged in groups of three, with each flower lasting for about one day. They are pollinated by bees and other insects.


The number of Spiderwort plants in the single Alberta location varies from year to year depending on moisture conditions. In wet years there can be as many as 37,000 plants. In some dry years, only 20-30 plants are found.


Current Threats

  • The biggest threat to Spiderwort is the stabilization of sand dunes. In the past, sand dunes were kept active through a combination of wildfire and grazing by Bison.
  • In Saskatchewan and Manitoba, a non-native plant, Leafy Spurge, has invaded all Spiderwort sites, reducing the amount of available habitat. While the Alberta site is free of Leafy Spurge, another non-native species, Baby’s Breath, has been found in the area.
  • Industrial activity (seismic lines and well sites) has the potential to directly remove habitat and plants and bring non-native plants in to the area.
  • Sand extraction for road construction and industrial activities.
  • Lack of genetic diversity in the Alberta population because of the wide geographic separation from populations in Canada and the USA makes this species prone to being extirpated.

Species@Risk Quiz

Test your knowledge about Alberta’s grassland species at risk

Western Spiderwort

Congratulations - you have completed Western Spiderwort. You scored %%SCORE%% out of %%TOTAL%%. Your performance has been rated as %%RATING%%
Your answers are highlighted below.
Question 1

Western Spiderwort got its name from:

The spiders that pollinate it
The web-like threads that form when the stem and leaves are injured
Its spider-like flowers
Question 2

Western Spiderwort was first found in Alberta in:

The early 1900s
Question 3

Other species found in Alberta’s sand dune habitats include:

Ord’s Kangaroo Rats
Tiger Beetles
Western Hognose Snakes
All of the above
Question 3 Explanation: 
(Kangaroo Rats, Tiger Beetles & Hognose Snakes), although they not necessarily occupy the same dunes as the Western Spiderwort. Check out MULTISAR’s website for more information.
Question 4

To protect Western Spiderwort habitat, volunteers have been busy removing:

Baby’s Breath plants
Once you are finished, click the button below. Any items you have not completed will be marked incorrect. Get Results
There are 4 questions to complete.


  • Volunteer for Adopt-a-Plant Alberta, a group that participates in recovery efforts for plants at risk.
  • Report observations of Western Spiderwort to your local Alberta Environment and Parks biologist.
  • Support native grassland habitat by choosing grass-fed meat in the grocery store.
  • Voice your support for native grassland conservation with your political leaders.
  • Educate yourself and your family about Western Spiderwort and other plants and animals that rely on sand dune habitats.


  • Ensure prompt identification and removal of non-native invasive species from sand dune areas, especially Baby’s Breath and Leafy Spurge.
  • Adopt low to moderate intensity grazing practices that maintain active sand dunes.
  • Talk to your children and neighbours about the privilege of having this unique plant on your land.
  • Contact MULTISAR to discuss management practices that might be beneficial to Western Spiderwort on your property.


  • Provides information on how to identify Western Spiderwort and recommends beneficial management practices that will allow this rare plant to thrive.
  • Provides  information on non-native invasive weeds that threaten Species at Risk and rangelands and ways to control them.