Chrysanthemums are one of the most popular flowers in Europe and rest of the world as well. But apart from Asia they are still one of the least known herbs and vegetables. There are few species of which flower buds are playing significant role in Chinese Traditional Medicine and other ancient medicinal systems (the most popular are C. morifolium ( ju hua ) and indicum). And there are three that are valiable vegetables as well. Chrysanthemum carinatum, syn. C. tricolor is quite unique and it's native to north Africa, while two others seems to be closely related.
One is a forgoten european - Chrysanthemum segetum (a.k.a. Corn marigold in Britain) and another one is asian - Chrysanthemum coronarium, which probabily derives from its ancestor Midditerean form. First one is nowadays used culinary probabily only on the Isle of Crete where it's called Mantilida (more precisely, it's probably hybrid of both, also known under latin name of C. coronarium), while the second one is hugely popular in the whole of south-east Asia, and apart from using for cooking and as a fresh vegetable, it's also used as a medicine.
In Britain it's barely known but it has its own names - Crown daisy, Garland Chrysanthemum, Chrysanthemum greens but it's also known as Chop Suey, which comes from the name of popular Asian dish made from this veg. Most popular names of these greens are Tangho, Ai Cai in China, Shungiku,Kikuna in Japan and Tan O in Vietnam. In my opinion this very easy to grow annual is realy tasty and deserves to be just as popular in Europe and other temperate climate regions as letuce or parsley.
CULTIVATION AND HARVESTING
Chrysanthemum coronarium is very easy to grow outdoors in a temperate climate. It is herbaceous annual, growing up to meter high and if you cut tops it can be very bushy. Its seeds germinate well sown just straight on a surface of soil even when temperatures are around 8'C, it is growing even in temperature's between 0'C to 5'C and can withstand light frosts. Biggest and best crops are when plants have good compost, neutral or slightly acidic soil, around 20'C, with high humidity and partial shade. In higher temperatures, dry conditions and strong sunlight, plants are starting to produce flowers rapidly and its leaves are becoming bitter. If you continue to harvest tops, leaving a bit of leaves and not letting the plant to flower. You can have nice greens from the same plant from last to first frosts. And I presume that in greenhouses it might become even biennial veg. But plants produce seeds easily, which like I've mentioned sprouts easily too, so you can just grow new plants and harvest old ones just above roots only leaving some to produce you new seeds.
Leaves, and whole young, soft stems are tasty, mild, slightly bitter vegetable with characteristic Chrysanthemum aroma. They both have a plasant succulent, crispy texture as long as they are freshly picked from plants that had been watered enough. It can be used for sandwiches and salads or chopped and mixed with white cheese the same way as rucola. As for cooking, it have many uses, which is why these greens are so popular in Asian cusines. They can be pickled, fried in tempura batter, stir-fried, steamed or cooked in soups and stews added near the end of cooking to avoid overcooking. In Japan a pickle called Kikumi is made from flower petals, they also dip flowers in sake and eat as an apetizer. Centre of flowers is rather chewy, very bitter and aromatic, while petals are very subtle both in texture and taste, distinct from green parts. Flowers can be also dried for a herbal tea.
Excess consumption should be avoided as plant (especially center of flower bud) contains pyrethrin, which is potentialy harmful in large doses. This plant may cause allergic reactions especially on people that are allergic to ragweed, dandelion, goldenrod, sunflower or daisies. It should be avoided by people taking medications for conditions like high blood presure, gout, HIV, herpes, immunosupressants or insuline. Because of lack of reaserch it is advised to be avoided by pregnant or breastfeeding women.
''Complete Book of Vegetables'' - Matthew Biggs, Kyle Cathie Limited 2010
''The Royal Horticultural Society Encyclopedia of Herbs & Their Uses'' - Deni Brown, DK 2002
''Honey, Wild flowers & Healing plants of Greece'' - Myrsini Lambraki, Myrsini Lambraki 2003