Plant DetailShow Menu

Mexican Thistle Argemone mexicana

Previously known as:

  • Argemone leiocarpa
Phonetic Spelling
ar-GEH-mon-ee meks-sih-KAY-nah
This plant has high severity poison characteristics.
See below
Description

Originally from Mexico, Prickly Poppy has naturalized in many parts of the world.  In regions that experience a pronounced dry season, it can be found growing in its natural habitat of dry soils along roadsides, waste places and fields.  In more temperate locations, it can flower and produce seed year round.  

In many locations worldwide, it has become a nuisance plant in crops and is listed as a serious agricultural weed.  Where fields or pastures have been overgrazed, its invasive nature has allowed it to multiply.  In addition to humans, this plant is toxic for grazing animals.

The solitary, showy flowers form at the tips of the branches.  When cut, a yellow juice or sap is exuded.  The leaves are thistle-like and are not attached to the stem by petioles.  The grayish-white veins on the leaves stand out against the blue-green leaf surface.  

Insects, Diseases, and Other Plant Problems:  White flies, thrips and aphids can affect this plant. All parts of this plant are toxic if ingested.  The level of toxicity varies depending on the person's size, age, and physical condition.  Alkaloids from the plant are similar to those found in opium poppy.  

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#poisonous#drought tolerant#white flowers#yellow flowers#frost tender#high maintenance#fast growing#aggressive#deer resistant#cream flowers#fields#self-seeding#poor soils tolerant#dry soils tolerant#colonizing#salt spray intolerant#salt intolerant#self-fertile#shade intolerant#showy#weed#pasture
 
Cultivars / Varieties:
Tags:
#poisonous#drought tolerant#white flowers#yellow flowers#frost tender#high maintenance#fast growing#aggressive#deer resistant#cream flowers#fields#self-seeding#poor soils tolerant#dry soils tolerant#colonizing#salt spray intolerant#salt intolerant#self-fertile#shade intolerant#showy#weed#pasture
  • Attributes:
    Genus:
    Argemone
    Species:
    mexicana
    Family:
    Papaveraceae
    Uses (Ethnobotany):
    Oils extracted from the seed are used for lighting and for producing soap.  It has also been used on wood as a treatment for termites.
    Life Cycle:
    Annual
    Recommended Propagation Strategy:
    Seed
    Country Or Region Of Origin:
    Central Mexico to Honduras
    Distribution:
    AL, AZ, CT, DC, DE, FL, GA, HI, IA, IL, IN, KS, LA, MA, MD, MI, MO, MS, NC, NJ, NY, OH, PA, SC, TN, TX, VA, VT
    Wildlife Value:
    Bees, flies and beetles frequent this plant.
    Play Value:
    Attractive Flowers
    Buffer
    Easy to Grow
    Wildlife Larval Host
  • Whole Plant Traits:
    Plant Type:
    Poisonous
    Habit/Form:
    Erect
    Growth Rate:
    Medium
    Maintenance:
    High
    Texture:
    Medium
    Appendage:
    Prickles
    Thorns
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Soil Texture:
    Sand
    Soil pH:
    Acid (<6.0)
    Neutral (6.0-8.0)
    Soil Drainage:
    Good Drainage
    Very Dry
    Available Space To Plant:
    12 inches-3 feet
    NC Region:
    Coastal
    Piedmont
    USDA Plant Hardiness Zone:
    7a, 7b, 8b, 9a, 9b, 10a, 10b
  • Fruit:
    Fruit Color:
    Green
    Display/Harvest Time:
    Fall
    Spring
    Fruit Type:
    Capsule
    Fruit Length:
    1-3 inches
    Fruit Width:
    1-3 inches
    Fruit Description:
    The fruit will split open after drying.
  • Flowers:
    Flower Color:
    Cream/Tan
    Gold/Yellow
    White
    Flower Inflorescence:
    Solitary
    Flower Value To Gardener:
    Long Bloom Season
    Showy
    Flower Bloom Time:
    Spring
    Summer
    Flower Shape:
    Cup
    Flower Petals:
    4-5 petals/rays
    6 petals/rays
    Flower Size:
    1-3 inches
    Flower Description:
    Flowers have 4-6, bright yellow petals (cream-yellow or white forms) and many stamens.
  • Leaves:
    Leaf Color:
    Blue
    Gray/Silver
    Green
    Leaf Feel:
    Leathery
    Smooth
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Obovate
    Leaf Margin:
    Dentate
    Lobed
    Hairs Present:
    No
    Leaf Length:
    > 6 inches
    Leaf Width:
    1-3 inches
    Leaf Description:
    Leaves are alternate, simple, with spine-tipped lobes and whitish wax that rubs off. The upper leaves clasp the stem between its lower loves. The upper surface has a smooth feel.
  • Stem:
    Stem Is Aromatic:
    No
    Stem Cross Section:
    Angular
    Stem Form:
    Straight
    Stem Surface:
    Smooth (glabrous)
    Stem Description:
    The branched, upright stem can be smooth or slightly prickly.
  • Landscape:
    Attracts:
    Bees
    Resistance To Challenges:
    Deer
    Drought
    Dry Soil
    Poor Soil
    Problems:
    Poisonous to Humans
    Problem for Horses
    Spines/Thorns
    Weedy
  • Poisonous to Humans:
    Poison Severity:
    High
    Poison Symptoms:
    TOXIC ONLY IF LARGE QUANTITIES EATEN. Poisonous through ingestion. (Poisonous parts: All parts, seeds). Symptoms may include: Vomiting, diarrhea, difficulty of seeing, fainting, and coma.
    Poison Toxic Principle:
    Isoquinoline alkaloids
    Causes Contact Dermatitis:
    No
    Poison Part:
    Bark
    Flowers
    Fruits
    Leaves
    Roots
    Seeds
    Stems