About
Find Nurseries
Design & Inspiration
California Garden Planner
Bay Area Garden Planner (NEW)
Planting Guide
Butterflies
My Plant Lists
Contact Us
Sign In
Donate
Advanced Search
Contact Us
Sign In
Donate
Home
Advanced Search
Map Locator
View Settings
Nurseries Carrying this Plant
Add Current Plant To List
Edit Current Plant
Show all Photos
About Calscape
Nurseries
California Garden Planner
Bay Area Garden Planner (NEW)
Planting Guide
Butterflies
My Plant Lists
Contact Calscape
Donate
Tap map to see plants native to location
Print Plant Signs
Print Plant Labels
Export To Excel
Export To Excel (Detailed)
Order by Popularity
Order by Common Name
Order by Scientific Name
Order by # of Butterflies Hosted
Show nursery cultivars
Hide nursery cultivars
Show plants not in nurseries
Hide plants not in nurseries
Grid view
Text view
Home
>
All plants
for California
>
Erigeron canadensis
|
Previous
Next
Loading....
Processing the request......
Horseweed
( Erigeron canadensis )
Erigeron canadensis
More Photos at CalPhotos
More Info at Jepson eFlora
Calflora
Click on blue squares to see occurrence records.
<< Plant species
Zoom To My Address
Zoom To California
Estimated Plant Range (
?
)
occurrences >>
All Occurrence Records
0 Nurseries Carry This Plant
Add to My Plant List
About Horseweed (Erigeron canadensis)
0 Nurseries Carry This Plant
Add to My Plant List
Conyza canadensis (sometimes called
Erigeron canadensis
L. ) is an annual plant native throughout most of North America and Central America. It is also widely naturalized in Eurasia and Australia. Common names include horseweed, Canadian horseweed, Canadian fleabane, coltstail, marestail and butterweed. It was the first weed to have developed glyphosate resistance, reported in 2001 from Delaware. Horseweed originated in North America and is very widespread there, but has spread to inhabited areas of most of the temperate zone of Asia, Europe, and Australia. It is much the most common of the alien Conyza species in Britain, and is found from northern Scotland to Cornwall. It is the only one of the British Conyza species that grows as a weed of arable land: the others are casuals of waste and disturbed ground in towns and by roads and railways. It is not invasive of any natural or semi-natural habitats. Conyza canadensis is an annual plant growing to 1. 5 m (60 inches) tall, with sparsely hairy stems. The leaves are unstalked, slender, 2-10 cm long and up to 1 cm (0. 4 inches) across, with a coarsely toothed margin. They grow in an alternate spiral up the stem and the lower ones wither early. The flowers are produced in dense inflorescences 1 cm in diameter. Each individual flower has a ring of white or pale purple ray florets and a centre of yellow disc florets. The fruit is a cypsela tipped with dirty white down. Conyza canadensis can easily be confused with C. sumatrensis, which may grow to a height of 2 m, and the more hairy C. bonariensis which does not exceed 1 m (40 inches).
Plant Description
Plant Type
Annual herb
Size
4.9 ft tall
Flower Color
White, Yellow
Wildlife Supported
Butterflies & moths hosted ( 14
likely
* )
SHOW ALL
*
Northern Checkerspot
Chlosyne palla
Chlosyne palla
*
Gabb's Checkerspot
Chlosyne gabbii
Chlosyne gabbii
*
Pearl Crescent
Phyciodes tharos
Phyciodes tharos
*
Sierra Nevada Checkerspot
Chlosyne whitneyi
Chlosyne whitneyi
*
White-lined Sphinx
Hyles lineata
Hyles lineata
*
Wavy-Lined Emerald
Synchlora aerata
Synchlora aerata
*
Common Eupithacia
Eupithecia miserulata
Eupithecia miserulata
Landscaping Information
Common uses
Bee Gardens
Natural Setting
Climate
Annual Precipitation: 2.7" - 77.2", Summer Precipitation: 0.14" - 2.69", Coldest Month: 30.9" - 59.0", Hottest Month: 57.0" - 88.0", Humidity: 0.45" - 38.66", Elevation: -4" - 6921"
Alternative Names
Common Names
: Canadian Horseweed
Print Plant Sign
Print Plant Label
Back
Print
Back
Print
Horseweed
Erigeron canadensis
Sources include:
Wikipedia
. All text shown in the "About" section of these pages is available under the
Creative Commons Attribution-ShareAlike License
. Plant observation data provided by the participants of the
California Consortia of Herbaria
, Sunset information provided by
Jepson Flora Project
. Propogation from seed information provided by the
Santa Barbara Botanical Garden
from "Seed Propagation of Native California Plants" by Dara E. Emery. Sources of plant photos include
CalPhotos
,
Wikimedia Commons
, and independent plant photographers who have agreed to share their images with Calscape. Other general sources of information include
Calflora
,
CNPS Manual of Vegetation Online
,
Jepson Flora Project
,
Las Pilitas
,
Theodore Payne
,
Tree of Life
,
The Xerces Society
, and information provided by CNPS volunteer editors, with special thanks to Don Rideout. Climate data used in creation of plant range maps is from
PRISM Climate Group, Oregon State University
, using 30 year (1981-2010) annual "normals" at an 800 meter spatial resolution.
Links:
Jepson eFlora Taxon Page
CalPhotos
Wikipedia
Calflora
Sign in to your Calscape Account
X
Once signed in, you'll be able to access any previously saved plant lists or create new ones.
Email Address
Password
Sign In