Field Penny Cress – Thlaspi arvense

Field Penny Cress (Thlaspi arvense) is also known as Field Pennygrass and is a member of the Mustard Family. This plant plant can reach a height of 40 cm with the stem being unbranched and bristly with a mustard like fragrance.

The flower is white and roughly 0.5cm wide with 4 petals, 3 – 4mm in length and also has 6 stamens, 4 of these are long and 2 are short, with yellow anthers.  The leaves form a rosette at the bottom, with leaves alternating up the stem with stalked basal leaves.

Field pennycress has oval, flat pods which make it easy to recognise. When the plant begins to flower the leaves at the lower part of the stem begin to turn yellow. The pods themselves stay green for a long period of time and the pods develop with each of them containing around a dozen seeds in each. The pod itself has been described as looking like , a coin, a purse or a pocket.
Some of the other well known names refer to its onion / mustard fragrance and if it is eaten by cows it has been known to flavour the milk or butter.

Height: 20 -60cm
Flowering Time: May to July
Preferred Conditions: Typically found in rich soil and wasteland areas.

Field Penny Cress - Thlaspi arvense