Stevens County Noxious Weed Control Board
This web site will help you identify & control noxious weed with information and photographs to aid you.

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Dwarf snapdragon
Chaenorrhinum minus L.              
Figwort family

Key identifying traits

  • Short upright plant usually under 8 inches tall
  • Glandular hairs cover the entire plant
  • Lower leaves opposite and oblong; others alternate and linear, 3/8 to 1 Ό inches long
  • Flowers resemble toadflax or snapdragon, but have a short spur; 2-lobed upper lip and a 3-lobed lower lip with outside of the flower bluish purple
  • Flower is about Ό inch long & remains in bloom for only 24 hours
  • Fruit is egg shaped containing dark brown seeds

Biology and ecology

  • A summer annual with a small taproot
  • Found almost exclusively on bare dry sites; often along railroads or roads in the intended bare zone
  • Reproduces by seed and flowers in about 45 days
  • Mature plants are brittle and break off easily
  • Seeds are released through two round pores at the top of the capsule, 40-60 per capsule; when wet the capsule closes preventing seed escape
  • A single seed can start a population of this self-fertilizing plant

Control

Prevention – Learn to identify plants; know your property; beware of bare soil near roads or RR

Biological – None known at this time

Cultural – Good competitive vegetation is the best protection from infestation

Mechanical – Tillage and pulling work well but can’t be mowed low enough and often enough

Chemical – The PNW Weed Management Handbook does not have this weed listed for control recommendations, but glyphosate may be a good choice along road shoulders or driveways where injury to other plants can be tolerated

dwarf snapdragon in the center of the "dead zone" along the highway


Where found –
Found along a short portion of HW395 south of Chewelah in Stevens County. Found along some railroad tracks in Spokane County and in many parts of the US.

MSdoc     pdf

 

weedboard@co.stevens.wa.us
Last Edit: March 25, 2015
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