Bonhoeffer Botanical Gardens exists to showcase the 900 unique species of plants that exist in the Cascadia Floristic Region. Over 600 species have been supplied by native plant nurseries or grown from seeds collected in the Wilds. A few “exotics” or non-native plants (or animals) that are not found in Cascadia naturally (introduced by accident or intentionally) have been allowed to “take root.” Reason: 1) just because they are beautiful and 2) they can’t be controlled. We call them “Pioneer Species.”

https://en.wikipedia.org/wiki/Glossary_of_botanical_terms

Pioneer Plant Species (exotics)
      Butternut Trees
      Canada Goldenrod
      Dandelions 
      Evergreen & Himalayan Blackberries 
      Foxgloves 
      Holly