07/24/2026
Water Primrose might look like a harmless shoreline flower, but it’s one of the most aggressive threats to Pacific Northwest waterways.
Water Primrose (Ludwigia hexapetala) doesn’t just grow; it takes over. It forms thick floating mats that block water flow, trap sediment, and reduce oxygen levels for native fish and wildlife.
How to identify it:
• Bright yellow, 5-petaled flowers
• Long willow-like leaves
• Dense floating mats spreading across the shoreline
The biggest challenge is spread. Water Primrose reproduces through seeds and fragmentation, meaning broken stems can drift downstream and start entirely new infestations.
That’s why aggressive pulling or cutting often makes the problem worse.
Our team uses targeted removal methods like DASH (Diver Assisted Suction Harvesting) and benthic mats to help control invasive growth while minimizing fragmentation.
If your shoreline is disappearing under a carpet of green and yellow, let’s walk your space and build a plan.
Your Vision is Our Mission.
WA REG No. SAMPSBS764C8
OR CCB No. 260780
Photo credit: Tualatin Soil & Water Conservation District