Common Tellweed: Intolerance & Allergy

Common tellweed is a flowering plant that grows wild in Northwest America and now also in Europe. Due to its high nutrient and vitamin C content, it is still popularly eaten as a salad or vegetable garnish.

Here’s what you should know about common dishweed.

Common tellweed is a flowering plant that grows wild in Northwest America and now also in Europe. Due to its high nutrient and vitamin C content, it is popularly eaten as a salad or vegetable garnish. The common tellweed belongs to the genus of tellweeds (lat. Claytonia). In German it is also called Cuba spinach, winter purslane or postelein. In total, there are 26 different species of tellweed. The common tellweed is easy to distinguish from most of these species, because in it the uppermost leaves unite into a single bract that surrounds the stem. This gives the impression that the flower stalk grows through the leaf, which is also expressed by the Latin species name “perfoliata” (= through the leaf). The remaining leaves are rhombic to ovate and have a long stalk. The inflorescence above the collar-like bracts consists of 5-40 flowers. The small, mostly white flowers show five petals, indicating that they belong to the plant order of cloves (Caryophyllales). The common tellweed germinates in autumn at temperatures below 12 °C. Depending on the course of the winter, larger plants can be found as early as October, and in cold winters from February. The flowering period lasts from February to May. At the end of May the plant dies and only the seeds survive the summer in the soil. The plant is edible including flowers and root. It tastes mildly sweet and nutty. The common tellweed has retained its preference for cool, not too bright locations from its original home, the mountainous regions of southern Alaska to Central America. The German name Kuba-Spinat indicates that English settlers brought the plant to Cuba because its consumption provides good protection against scurvy, a vitamin C deficiency. From there it spread to Australia and Europe. It is attested that the botanist Archibald Menzies cultivated specimens of the plant in Kent Garden in 1794 and thus brought it to Europe. In northern and northwestern Germany, common tellweed thrives in fields and gardens as a “weed,” but is also cultivated in greenhouses and grown for consumption. Common tellweed is the only species of its genus that grows in Europe.

Importance for health

Common tellweed is the first useful plant that can be harvested and eaten fresh at the beginning of a new year. The Indians and European settlers were able to protect themselves from scurvy through Claytonia, because it has a very high vitamin C content. This property helped it gain popularity in its country of origin. In this country, too, the early ripening of the tellweed helps to bridge the time until the harvest of other useful plants, without having to resort to imported goods. Claytonia has remained a wild plant to this day and has not been altered by human intervention. Therefore, although the plant is small, it has an unusually high vitamin and nutrient content compared to other crops. As a wild plant, it contains high levels of chlorophyll, whose antioxidant components bind free radicals, slowing cellular aging. Uncooked, its consumption enhances the release of the happiness hormone serotonin. A typical leafy vegetable, Claytonia is low in fat and high in fiber. The common plate herb is often used in its native USA as an ingredient in vegetable smoothies or salads. It makes an excellent herbal companion to a diet or detoxification regimen. In addition, it can also be consumed cooked like spinach.

Ingredients and nutritional values

The common tellweed is a popular wild vegetable in the United States (“Miner’s lettuce” = “miner’s lettuce” called), so its ingredients have been studied by the authorities. The dry matter, excluding liquid components (water, fats), consists of 37% protein, 42.5% long-chain carbohydrates (sugars) and 12.4% fiber. A serving of about 100 g has about 20 kilocalories. This covers 33% of the vitamin C requirement of an adult, 22% of the required amount of vitamin A and 10% of the iron requirement.The plant has a very low content of oxalic acid, a harmful cytotoxin in larger doses, which is found in many other vegetable plants. Among the protein components there are many antioxidant substances from chlorophyll, e.g. beta-carotenes. Furthermore, Claytonia has a high content of omega-3 fatty acids, calcium and magnesium.

Intolerances and allergies

The most common allergens, such as pollen, nuts or gluten, bear no resemblance to ingredients of common tellweed. Therefore, most allergy sufferers can eat this plant without concern. However, there are people who suffer from a so-called “lettuce allergy“. The characteristics are swelling of the oral cavity, skin rash and complaints in the gastrointestinal tract. The allergic symptoms occur on contact with salads (lettuce, chicory), spices (tarragon, cardamom), spice teas (chamomile, yarrow) and certain vegetables (artichoke, salsify). People affected by lettuce allergy are not allergic to all of these plants at the same time or to the same degree. Most plants belong to the genus Asteraceae, but this is not an exclusion criterion. Scientists have identified the LPT (lipid transfer protein) Lac S1 as the causative allergen, which is also produced by non-corms. Therefore, anyone affected by a lettuce allergy should also be cautious when eating common tellweed.

Shopping and cooking tips

Common tellweed is mostly known by its vernacular names winter purslane and postelein in German markets. However, it is not a member of the Portulaca family and is not related to the similar-looking summer purslane. Common tellweed is offered at well-stocked weekly markets and is often found as a garnish in vegetable boxes that consumers can purchase directly from organic growers. Because of its distribution in northwestern Germany, winter purslane is rarely found in central and southern Germany. Winter purslane offered at markets usually comes from greenhouses. Since Claytonia perfoliata is now also native to our region, it can be grown by oneself or harvested in nature. Those who collect the plant in nature should do so at a sufficient distance from roads and other sources of pollution.

Preparation tips

In principle, you can harvest and eat the whole plant, but the roots should be cooked beforehand. If you do not want to eat the roots, you should harvest only the leaves. To do this, simply pluck the leaves carefully with the stem. Unless all the leaves are removed, the plant can form new leaves that can be harvested again later. Harvesting can begin with young plants as small as 5 cm and continue until the plant has faded. The leaves can be eaten raw after thorough washing. A number of tasty recipes can be found on the Internet as suggestions for further use.