Chelidonium majus (greater celandine)

Greater celandine is native to most of Europe and western Asia and introduced in North America. The species is perennial, and although flowers can occur first year, seeds will probably not develop until second year. The plants grow up to 40-60 cm. The whole plant is moderately toxic and when damaged the plant excretes a bright orange-yellow sap which can be irritating and allergenic. Chelidonium majus can easily self-sow and is in several regions and countries considered invasive.

Traditionally, it's been used as a drug to improve eyesight and the yellow sap from the plant has been used externally to treat warts and skin irritation like eczema. The species also has a mild sedative effect and relaxes the muscles, thus treating coughs, bronchitis, and asthma. Unlike some of the other medicinal species described in this project, Chelidonium majus is no longer used as a medicinal plant, except as an ingredient in some homeopathic medicines.

Sow the seeds in April/May in a broadcast tray under light conditions, approximately 20-23 °C. Initially cultivate in tray substrate. Cover seeds to a depth of 1 cm. The seeds tend to initially germinate unevenly. When large enough to handle transplant the plants into small individual pots in pot substrate. When no risk of frost, the pots can be placed in an unheated greenhouse, or outside. When the plants are fully rooted in the pots, transplant in field. It’s also possible to sow the seeds in August and plant them in field September/October. These plants will flower and produce seeds the following year. Position: shade, semi-shade or sunny.

Flowering time for Chelidonium majus is in May and quite short. Seed harvest will normally take place in June/July the second year. Always harvest in dry conditions. Note that the long, cylindrical capsules housing the seeds will burst and spread the seeds on the ground when mature. Even if the plant produces many seeds, do not wait too long harvesting the seeds to avoid spreading. The best way to harvest the plants is to cut the stem with a pair of scissors below the cylindrical capsules when mature. Both the stem and the capsules should be dry and brownish. Remember to use gloves when handling the plants since the sap of the plants can be irritating to your skin.