The Western Washington macro-invasive plants.

Invasive Blackberry and English Ivy

Our invasive blackberry and the ornamental ground cover English Ivy are serious threats to native vegetation. The density and abundance of English Ivy on the ground prevents other plants and trees from growing up and out of the ivy. Generally speaking, English Ivy and Blackberry pose very long-term threats to slope stability and other native critical areas. We treat our Blackberry in the summer with a mix of multiple herbicides. We treat our English Ivy in the winter, also with multiple herbicides. These weeds are controllable and we do so every year.

Places where English Ivy causes most problems:

  • Shorelines
  • Steep slopes
  • Riparian slopes
  • Steep hillsides 


Places where Blackberry causes most problems: 

  • Riparian corridors and slopes
  • Disturbed areas
  • Wetlands
  • Pastures 

Multiple Treatments

A single treatment of herbicide is rarely enough to treat these aggressive, exotic plants. Normal restoration sequencing is 2-4 treatments over 6-24 months. 

Long-term Preservation

Noxious weeds don’t normally affect ecology on the short-term. On the long-term there exist serious consequences to neglected vegetation and unmanaged weeds. 

Reinstallation of Native Flora

Simply removing the invasive plant doesn’t mean natives will regrow. The Blackberry and Ivy will grow faster and out-compete our native flora easily. By first treating the infested area, then installing native flora, we give the native plants a much higher chance of survival and overall restoration success. 

Ecologically Sound Techniques

We take pride in our ecological soundness. We always take the least toxic and least impactful approach to restoration practices.

Case study – City of Olympia

In 2012, principal John Bornsworth, performed a series of forest landscape surveys in Priest Point Park in Olympia. These surveys represented all 300 acres of the park and their forest maturation, forest species present and native regrowth. After analysis of the data returned, it was apparent the areas of the Park infested with a thick ground cover of English Ivy were experiencing no coniferous or deciduous tree regrowth. The invasive Ivy practically arrested natural forest succession. In 20-50 years if left unmanaged, the current trees would begin dying and there would be no younger trees taking their place. In 100 years the 300 acre forest could of had very few naturally grown trees. From this data, the Park has begun a program to drastically reduce the presence of English Ivy.

Examples: