Blackberry at Lake Sammamish State Park: Show Us Your “Heart”
Blog Written by Dan Hintz, FLSSP Board Member, Restoration Committee Chair
Take a walk along Issaquah Creek or Tibbetts Creek at Lake Sammamish State Park and you will see a landscape in transition. The riparian buffers of these creeks are dotted with recently planted native conifers and fast-growing red alder, cottonwood, and willow trees, but you can never fully escape the presence of one of the most ubiquitous plants in western Washington, Rubus armeniacus.
Rubus armeniacus is the scientific or botanical name for what is more commonly known as Himalayan blackberry (a misnomer, as this species of blackberry is native to Armenia and northern Iran, not the Himalayas). Introduced to the United States in 1885 by horticulturalist Luther Burbank (read more about The Strange, twisted story behind Seattle’s blackberries from KUOW), it was first planted in California as a vigorous, easy to grow plant with the ability to produce lots of tasty berries (which we still enjoy today). Unfortunately, blackberry quickly escaped and is now considered naturalized throughout much of the pacific northwest.
Due to past land use in what is now Lake Sammamish State Park, blackberry took hold and thrived throughout the 20th century. During much of that timeframe, the Park property was used for agriculture, involving primarily hayfields and pasturelands. Blackberry is a species that loves to invade disturbed areas (like clear cuts) and thrives in full sunlight. Once it takes hold, it forms monocultures (a single dominant species) that prevent the growth of native vegetation that is vital for wildlife. A single blackberry cane (or vine) can grow upwards of 20-30 feet each year!
In 2005, Washington State Parks commissioned the Lake Sammamish State Park Wetland, Stream and Lakeshore Restoration Plan that set out goals and priorities for ecological restoration of the 530 acre State Park. Since then, State Parks, Mountains to Sound Greenway, Friends of Lake Sammamish State Park, Trout Unlimited, the Snoqualmie Tribe, and thousands of volunteers have given their blood (those blackberry thorns will scratch you like your cat!), sweat, and hopefully not too many tears cutting back and digging out blackberry root balls to make room for the planting of native tree species to restore habitat for salmon and other wildlife along Issaquah and Tibbetts Creeks.
In 2005, it was estimated that there was over 100 acres of blackberry within Lake Sammamish State Park, which is about 20% of the Park landmass. These restoration efforts have significantly reduced the cover of blackberry and replaced it with native tree species that surrounded these creek corridors for millennia prior to modern day land disturbances. These efforts take time, but have been very successful in restoring riparian forest habitats.
FLSSP has dedicated monthly volunteer events on third Saturdays where members of the community can come out and tackle more blackberry and take care of the small trees and shrubs planted to replace, and in time, shade out the blackberry. It is not too late to sign up to join us this Saturday, April 20th to pull some blackberry at the Tibbetts Creek Site - register here to join us on Saturday April 20th from 10 am - noon.
The blackberries store their energy in “root balls” or “blackberry hearts” that need to be dug out to keep the plant from growing back. This growing season, join FLSSP in a friendly competition to remove blackberry hearts and #keepyoureyeontherootball! This summer, at both FLSSP events and in your garden, don't just mow it, dig in and show us your “heart!”
Join our #keepyoureyeontherootball contest by:
1. When removing blackberries, dig out those root balls!
2. Take a photo with your root ball and something for scale
3. Tag FLSSP @flssp123 and #keepyoureyeontherootball
4. At the end of the season, FLSSP will award prizes (2) for the biggest and craziest root balls submitted to the contest!
2002 Issaquah Creek prior to restoration efforts. Light “fluffy” green color is blackberry. Highlighted area shows 0.8 acres in 2002 which grew to 2.0 acres by 2017 (see next photo).
2017 Aerial view of Issaquah Creek. Highlighted blackberry portion more than doubled over 15 years. You can also see all the tiny trees dotting the creek buffer, slowly but surely replacing blackberry.