Mexican poppy is poisonous to stock, but few deaths occur because the plant is not readily eaten. This is due to the bitter sap which makes it unpalatable to stock. However some stock have died after eating contaminated hay or chaff and poultry after eating seeds. Mexican poppy seeds could be harvested with a wheat crop, thus contaminating the grain. However the seeds are much smaller than wheat grains and can easily be removed by seed cleaning.
Mexican poppy infested grain is unsuitable for milling or stock feed.
Description Mexican poppy grows up to one metre in height. It has typical poppy flowers, hollow stems and seed capsule. However prior to flowering it resembles a thistle because of its toothed and prickly leaf margins. The plant is bluish-green in colour with waxy marbling to the leaves. The leaves, which grow up to 20 cm long are silvery green with white veining and deep regular lobes.