1. Welcome to The Archuleta County Weed Tour
A Special thank you to the Peak Deli, the San Juan Conservation District, and the Town of Pagosa Springs for providing, food, resources, and space.
This is put on by the Archuleta County Weed and Pest and CSU Extension and is funded by CDA Grants

2. What is a Weed? Several definitions Simplest: A plant out of place
Weed is a loser’s term for success
When to manage weeds?
Economic thresholds
Aesthetic reasons
Noxious designation
(Curly dock) notey.com

3. What are Noxious Weeds? Introduced No benefits/harms Agriculture
Native environments
Economic value
Human Health

4. Why do we care about noxious weeds?
Legal mandate for control
Land stewardship
Cost associated with noxious weed infestations
Decrease home value, cost money to control, etc

5. List A Species Eradication is mandated by the State of Colorado
Species are not prevalent but have established a foothold
Eradication is an achievable short-term goal

6. Myrtle Spurge Euphorbia myrsinites Perennial Extensive root system
Milky latex that may irritate skin and eyes
Fleshy stems/tendrils
Low growing
Capsules explode to spread seeds

7. List B Species
Weed management plans are implemented to stop the continued spread of these species
Prevalent in Colorado
Containment is the short-term goal for these species

8. Black Henbane Hyoscamus niger Biennial
Hairy leaves, with pale mid-vein
Brownish yellow leaves w purple veins
Foul odor
All parts are poisonous

9. Houndstongue Cynoglossum officinale
Red or purple-red flowers on a single stem
Four barbed fruits produced per flower (burs)
Deeply veined leaves, veins don’t reach leaf margin

10. Hoary Cress (White Top)
Cardaria draba
Perennial
Four petaled white flowers
Blue-green leaves, lance shaped, clasp stem
May grow up to two feet tall

11. Perennial Pepperweed Lepidium latifolium Perennial Spoon shaped leaves
Dense clusters of white flowers
Stems and leaves have a waxy coating

12. Jointed Goatgrass Aegilops cylindrica Winter annual
Flowers in early June
Similar in appearance to wheat seed
Leaves have a flap-like appendage

13. Leafy Spurge Euphorbia esula Perennial Extensive root system
Stems exude a milky latex
Bright green-yellow color easily recognizable
Capsules explode to spread seeds

14. Yellow Toadflax Linaria vulgaris Perennial
Yellow flowers with orange throat, resemble snapdragons
Narrow, lance shaped leaves
Vegetative propagation

15. Dames Rocket Hesperis matronalis Biennial or short lived perennial
Upright hairy stems
Leaves are toothed and have short petioles or lack petioles
Four petaled, purple flowers in terminal racemes

16. Oxeye Daisy Chrysanthemum leucanthemum Perennial
Daisy-like flowers, 2” in diameter
Lance shaped, toothed, waxy leaves

17. Bull Thistle Cirsium vulgare Biennial Dark purple flowers
Leaves are prickly on top and wooly on bottom
Highly dissected leaves

18. Canada Thistle Cirsium arvense Perennial Flowers are white to purple
Lance shaped, spiny leaves
Spread via rhizomes

19. Musk Thistle Carduus nutans Biennial
Large ‘nodding’ pink to purple flowers (rarely white)
Leaves have white mid-vein and pale margins

20. Scotch Thistle Onopordum acanthium Perennial
Spiny wings attached to stems
Grayish blue in color due to dense hair on leaves
Can grow up to twelve feet tall

21. Diffuse Knapweed Centaurea diffusa Perennial
Flowers are white or light purple
Spiny bracts that appear yellow or brown
Plants may break from soil and spread seeds (tumble weed)

22. Russian Knapweed Rhaponticum repens Perennial
Urn shaped, purple flowers
Papery tipped bracts
Stems are thin and covered in a gray hair when young

23. Spotted Knapweed Centaurea stoebe Biennial Dark tipped bracts
Sage colored, dissected leaves

24. Russian Olive Elaeagnus angustifolia Tree
Growth ranges from ten to twenty five feet tall
Thorny branches
Stems, buds, and leaves are covered in grey scales

25. Salt Cedar (Tamarisk) Tamarix parviflora Tree
Small whitish or pink flowers
May reach heights of fifteen feet
Branches are brown covered in patches of white knobs

26. List C Species
These species are widespread and common throughout Colorado
Suppression and reduced reproductive success is the short-term goal for these species

27. Cheatgrass (Downy Brome)
Bromus Tectorum
Winter annual
Mature seed heads become imbedded in clothes or fur
4-30 inches tall
Drooping flowers

28. Common Mullein Verbascum thapsus Biennial
Yellow flowers grow in a stalk
Can grow up to six feet in height
Woolly leaves

29. Archuleta County Special Interest Weeds
Kochia is not on the noxious list, but its control and management is a special interest in Archuleta County
Other species may be managed if declared noxious by the Local Weed Advisory Board

30. Kochia Bassia scoparia Prolific seed spreader Tumble weed
Predisposed to acquire resistance
Pioneer species
Multiple flushes per year

31. Reporting invasive species with EDDMaps