A perennial, the Dandelion is a member of the sunflower family, the name comes from the French, 'dents de lion' ("teeth of the lion") due to the edge of the leaves resembling jagged teeth. A native to Europe, it is now widespread as it was taken around the world for its medicinal and culinary, uses. Dandelions are popular with beekeepers as they are an early source of nectar.
The dark green leaves form a rosette close to the ground which remain green all year round and are not killed by close mowing. The fleshy tap root goes down vertically and a small portion can regenerate if left in the soil. It is a resilient plant and can force its way up through tarmac. If a portion of root is left it comes back as a multi-crowned plant.
The flowers can be used to make wine, the leaves boiled like spinach or added uncooked to salads (the midrib is the bitterest part so tear of the softer green part). Young leaves growing in shade are less bitter. The roots are used as a vegetable or roasted and brewed for a coffee-like beverage. Dandelions used to be grown in unheated greenhouses to provide salad leaves in winter. Covering the plant with an upturned pot or bucket to block out light produces tender, blanched leaves after about 10 days, which are less bitter. They contain potassium (proportionately more than in bananas), sodium, phosphorus and iron. The leaves are a richer source of vitamin A than carrots and also have some C, E and B vitamins.
The Dandelion is one of the most frequently recorded plants in folk medicine. It is a mild laxative and diuretic, has been used for coughs and colds, as a tonic and blood purifier, for skin conditions, joint pain, eczema and liver conditions such as hepatitis and jaundice. It contains high levels of lecithin which reduces cholesterol so preventing strokes and heart disease. Its most popular use in folk medicine is for removal of warts by dabbing the white sap from the roots on them. In parts of Ireland the leaves were used as a remedy for toothache because of the leaf shape.
All parts of the Dandelion plant give off ethylene gas which can have an allelopathic effect on surrounding plants. Some fruit producers grow them below the canopy of their trees to promote even ripening. The leaves and flowers can be placed in a bag with fruit to help it to ripen. Ethylene released from the roots can have an inhibiting effect on the growth of neighbouring plants (allelopathy).
One of the more novel uses of Dandelions is to make rubber. The white sap or latex, contained in all parts of the plant can be converted to rubber by allowing it to dry. Coating a piece of fabric with it and letting it dry will make it waterproof, although it remains sticky - Charles Macintosh invented this by creating a sandwich with the rubber in the middle, hence why waterproof coats are called macintoshes or macs. Curing the crude rubber with heat and sulphur is the vulcanisation process in commercial production to stop the stickiness. The Russian Dandelion, Taraxacum kok-saghyz is a better source of the latex and has commercial uses.
When removing it dig up the whole plant using a fork to reduce the likelihood of breaking the root. Small fragments of roots will regenerate, so care must be taken during cultivation not to break them up. If repeated a few times you can eventually rid a lawn of an infestation by teasing out the plants, any part left will produce several new plants. Victorian gardeners would sever the root just below soil level and place a teaspoonful of salt on the remaining root. The younger the plant is the better the chance of complete removal.
A systemic weedkiller such as Glyphosate or a selective agent can be used, any flowers or unopened seedheads should be removed as they can mature before the plant dies away. Contact weedkillers destroy the topgrowth and must be repeated several times to be effective similar to the use of treatment with a flame gun.
A herbicide like Glyphosate is best. Pull off any flowers and buds as they can mature and produce seed before the chemical can act. In the lawn a selective weedkiller should work, or use Gylphosate as a spot weeder.
Follow these links for further details on Weeds, Weed Removal and Weed Prevention.