This friendly looking is plant popping up in lawns and parking strips across Portland, but don't be deceived!

It’s called lesser celandine.  Like a lot of invasive plants, it is able to out-compete native plants.  We need your help in the battle against invasives like this one.

Lesser celandine (Ranunculus ficaria) emerges earlier in the spring than many native plants, allowing it to overtake areas quickly.  This advantage allows lesser celandine to form dense patches displacing native plants, destroying wildlife habitat and ruining lawns.  Diverse native plants that provide nectar and pollen for pollinating insects and birds lose out.  Lesser celandine also dies back in the spring, which leaves hillsides and stream banks vulnerable to erosion that pollutes our rivers and streams. 

Lesser celandine grows above-ground from November to April, and flowers from late winter to early spring.  The leaves are dark green with silvery markings, shiny, succulent, and kidney- or heart-shaped.  The bright yellow flowers are often confused with the look-a-like marsh marigold (Caltha palustris), which is a native plant not known to occur in Portland metro region.  You can identify lesser celandine because of the three light green sepals behind its petals.  Lesser celandine produces finger-like tubers that form underground and tiny bulblets under the leaves.  The tubers, bulblets and seeds can all spread rapidly.

Removing this plant is tricky.  All parts of the plant as well as any soil near the plant must be placed in a bag and thrown in the trash. Tubers and bulblets must be dug up and disposed.  Due to this time consuming process, manual control (digging) is only recommended for small patches (less than six feet wide) and the site must be re-checked annually.  

Do not compost lesser celandine or try to save surrounding soil.  We encourage land owners to contact Environmental Services with any additional questions.  Find more information on City of Portland’s page about lesser celandine and from the Plant Conservation Alliance.

(photo: http://www.downgardenservices.org.uk/)

Flower sepals help identify the plant. (photo: http://www.illinoiswildflowers.info/)

Lesser celandine quickly took over this Portland yard!

Invasive species affect us all. They damage our forests, our streams and rivers, and our property.  Nationwide, damages associated with invasive species are estimated to be $120 billion each year.  In Oregon, the control of invasive weeds and the cost of the damages they create amounts to about $125 million each year.  We know that it costs a lot less to control new invasive plants before they become infestations, but we need everyone’s help.  Read more here about the problems caused by invasive species and why BES is particularly concerned about their impact on water quality.

Check out our previous posts on Alien Plant Invaders:

• English holly
• Spurge laurel
• Japanese and giant knotweed
• Ivy
• Pokeweed