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Thlaspi arvense

Common Name(s):

Phonetic Spelling
THLAS-pee ar-VEN-see
Description

Field Pennycress is an annual weed in the mustard family. It is native to Eurasia and is found in fields, along roadways and other disturbed areas. Its preference is for poor soils with some moisture in full sun but is tolerant of various conditions. It has a shallow root system and is easy to hand pull. It initially forms a rosette of leaves but these fade as the ribbed flower stem emerge. The flowers are tiny and white in elongated clusters with the flowers forming at the top and the fruits below. The distinctive seed pods are flat round papery pods with a top-notch that split to spill black seeds.

The mustard-garlic flavor of the leaves is not a favorite of grazing animals but the milk of dairy cows is affected if they eat it.

See this plant in the following landscape:
Cultivars / Varieties:
Tags:
#white flowers#weed#weedy#herb garden#pastures#disturbed areas#annual weed#problem for horses#roadside
 
Cultivars / Varieties:
Tags:
#white flowers#weed#weedy#herb garden#pastures#disturbed areas#annual weed#problem for horses#roadside
  • Attributes:
    Genus:
    Thlaspi
    Species:
    arvense
    Family:
    Brassicaceae
    Life Cycle:
    Annual
    Recommended Propagation Strategy:
    Seed
    Country Or Region Of Origin:
    Eurasia
    Distribution:
    Throughout N. America
    Wildlife Value:
    The nectar may attract small bees and flies. Some white butterflies and moths will lay their eggs on the leaves
  • Whole Plant Traits:
    Plant Type:
    Annual
    Herb
    Weed
    Habit/Form:
    Erect
    Growth Rate:
    Rapid
    Maintenance:
    High
    Texture:
    Medium
  • Cultural Conditions:
    Light:
    Full sun (6 or more hours of direct sunlight a day)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    Clay
    Sand
    Shallow Rocky
    Soil pH:
    Acid (<6.0)
    Soil Drainage:
    Good Drainage
    Moist
    NC Region:
    Coastal
    Mountains
    Piedmont
  • Fruit:
    Fruit Color:
    Brown/Copper
    Display/Harvest Time:
    Summer
    Fruit Type:
    Capsule
    Fruit Length:
    < 1 inch
    Fruit Width:
    < 1 inch
    Fruit Description:
    Fruit is a flat oval 2-parted pod about ½ inch long with a notch at the tip. It dries to a papery orange-tan shell. Each side of the pod holds up to 8 seeds that mature to nearly black.
  • Flowers:
    Flower Color:
    White
    Flower Inflorescence:
    Raceme
    Flower Bloom Time:
    Spring
    Flower Petals:
    4-5 petals/rays
    Flower Size:
    < 1 inch
    Flower Description:
    Elongating dense clusters of flowers form at the upper axils of leaves with small 1/8-1/4 inch white flowers opening at the top and fruit forming below. 4 white petals with 6 greenish-white anthers and a flat ovary. There are 4 green sepals with whitish edges below the petals.
  • Leaves:
    Leaf Color:
    Green
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Rosulate
    Leaf Shape:
    Oblanceolate
    Oblong
    Leaf Margin:
    Dentate
    Undulate
    Hairs Present:
    No
    Leaf Length:
    3-6 inches
    Leaf Width:
    1-3 inches
    Leaf Description:
    Initially, a rosette of oblanceolate leaves is formed with a rounded tip, entire to wavy margins and short stems. These fade early as the flowering stem arises with oblong, stalkless and clasping leaves. The margins have rounded to pointed teeth.
  • Stem:
    Stem Color:
    Green
    Stem Is Aromatic:
    No
    Stem Cross Section:
    Angular
    Stem Form:
    Straight
    Stem Description:
    Ribbed green stems may be branched at the top and may be winged
  • Landscape:
    Landscape Location:
    Meadow
    Problems:
    Problem for Horses
    Weedy