Dandelion

About

Dandelion is the weed most worth reconsidering.

It flowers in April when the first bumblebee queens, solitary bees and hoverflies are out and very little else is open, and it produces both nectar and a large quantity of pollen. A lawn full of dandelions in April is doing more for insects than most deliberately planted borders manage all year.

It is also edible in every part, from the leaves in salad through the flowers in wine to the roasted root as a coffee substitute.

Where it is a problem it is a serious one, and the reason is the taproot. It runs 25 cm and more into the ground, it is brittle, and any piece left behind regrows. Pulling the top off a dandelion achieves nothing at all.

Its seed is the other half. Each head produces around 150 seeds, each on a parachute that carries it hundreds of metres on the wind, and the plant sets seed without needing pollination, so every flower produces viable offspring.

In a border, a gravel drive or a paving joint it needs removing properly. In a lawn it is worth thinking about before reaching for anything.

Appearance and character

A herbaceous perennial forming a flat rosette 10 to 30 cm across, with flower stems to 30 cm.

Leaves are lance-shaped, 5 to 25 cm long, with deep backward-pointing triangular lobes along each side, hairless and bright green. The lobe shape gives the French name dent de lion, lion’s tooth, from which dandelion comes.

Flower stems are single, hollow, leafless and unbranched, and they bleed milky white latex when broken. Each stem carries one flower head.

Flowers open from March onwards, at their peak in April and May and appearing sporadically all year, 3 to 5 cm across, made entirely of bright yellow strap-shaped ray florets with no central disc.

Seed heads are the familiar clock, a sphere of around 150 seeds each on a fine parachute of hairs.

The taproot is fleshy, brown outside and white inside, running 25 cm or more down, and it bleeds latex when cut.

Taraxacum officinale is an aggregate of many hundreds of microspecies in Britain, most of which reproduce without fertilisation.

Where it is from

Europe and Asia, and native throughout Britain and Ireland, and it has been carried by people to almost every temperate part of the world.

It grows on grassland, roadsides, waste ground, lawns, pavements, walls and any disturbed or compacted soil.

The plant reproduces by apomixis, meaning it produces viable seed without pollination, so every flower sets seed regardless of whether an insect visits. That is why control by deadheading has to be complete rather than approximate.

Its value to insects is well documented. It is one of the most important early pollen and nectar sources in Britain for bumblebees, solitary bees, hoverflies and butterflies, and the April peak coincides with the emergence of queens.

Dandelion greens have been eaten across Europe since at least the middle ages, and the plant was cultivated as a salad crop in France, where selected large-leaved forms are still sold.

Roasted dandelion root as a coffee substitute dates from the eighteenth century and was widely used in Britain during both world wars.

The latex was investigated as a natural rubber source in the Soviet Union and again recently, using the related Russian dandelion.

How it spreads

By seed, overwhelmingly, and by regrowth from root fragments.

Each flower head produces about 150 seeds and a vigorous plant produces several heads a year.

Seeds are carried on the wind for hundreds of metres and germinate readily on almost any bare soil.

Seed is produced without pollination, so removing insects from the equation changes nothing.

The taproot regenerates from fragments. Cutting a dandelion off below the crown leaves a root that pushes up several new rosettes, so a badly removed dandelion becomes three.

Compacted ground favours it. A dandelion taproot penetrates hard soil that grass roots cannot, which is why they colonise worn lawns, path edges and trampled ground.

Through the seasons

Winter the rosette usually persists, flattened against the ground, and it flowers in mild spells.

Spring is the main flowering period, peaking in April and May, and this is when it matters most to insects.

Summer flowers sporadically and continues seeding, and it is the best time to lift plants from beds.

Autumn flowers again in a second smaller flush, and the rosettes build reserves for the winter.

Control in beds and paving

Lift the whole root. Use a long narrow dandelion weeder or an old kitchen knife pushed down beside the root, lever the plant out with as much taproot as possible, and check what comes up. A break at 5 cm leaves a root that regrows.

Do it when the soil is moist, after rain or watering, when the root comes out far more readily.

Repeat on anything that regrows, since a broken root produces multiple new rosettes and each is weaker than the original.

Remove the flowers before they seed even if you cannot lift the plant, cutting the stem at the base. A head cut in bud does not open, and a head already in flower will still form seed if left lying on the ground, so bag it.

Mulch beds thickly, which stops most seedlings establishing.

Fill and point paving joints, since dandelion in a joint is very hard to lift whole.

Treat individual plants in gravel or paving with a glyphosate gel painted onto the leaves where hand removal is impractical, following the label.

Improve compacted soil, which is what favours it, by aerating and adding organic matter.

Control in lawns

Decide first whether you want to. A lawn with dandelions in April is a significant insect resource, and a growing number of gardeners leave them for that reason or mow around them for a few weeks.

Lift them individually with a dandelion weeder where you want them out. It is slow, works, and does not affect anything else.

Mow regularly, which prevents seeding and weakens the plants over time without removing them.

Raise the mowing height, since a longer sward shades out dandelion seedlings and thickens the grass.

Aerate and feed the lawn, since dandelion colonises thin worn compacted turf and a dense sward resists it.

Use a selective lawn weedkiller where the infestation is heavy and you want a clean sward, applying in spring or early autumn when the plants are actively growing, and following the label. These products kill broadleaved plants and leave the grass, and they also remove clover, daisy, selfheal and everything else the insects use.

Consider a compromise. Keeping a formal lawn clean and leaving a rough area or an orchard strip unmown until June gives both a sward and the flowers.

Eating it

Every part is edible and worth knowing about.

Young leaves in early spring are the best, before the plant flowers, when they are least bitter. Use them raw in salad or cooked like spinach. Blanching a plant under a pot for a fortnight produces pale sweeter leaves in the French manner.

Flowers are made into dandelion wine, syrup and fritters, and picked on a dry day fully open.

Roots lifted in autumn, washed, chopped, dried and roasted make a coffee substitute with a bitter chicory-like flavour.

Avoid gathering from roadsides, from ground used by dogs, and from anywhere treated with herbicide.

Be certain of the identification. Dandelion has a single unbranched hollow stem carrying one flower, and no leaves on the stem at all. Several yellow-flowered lookalikes have branched or leafy stems and are less pleasant to eat.

Telling it apart

Dandelion has a single hollow leafless unbranched stem per flower, bleeding milky latex, and a basal rosette of deeply toothed leaves.

Catsear, Hypochaeris radicata, has branched wiry stems with small scale-like bracts on them and hairy leaves.

Hawkbit and hawkweed both have branched or leafy stems.

Sowthistle has tall leafy branched stems and prickly leaves.

Coltsfoot flowers in February on a scaly stem before its leaves appear.

The single unbranched hollow leafless stem is the reliable dandelion character.

Troubleshooting

Why does it keep coming back after I pull it? The taproot runs 25 cm or more down and regrows from any fragment. Pulling the top off achieves nothing. Use a long narrow weeding tool to lever the whole root out, and do it when the soil is moist.

It grew back as three plants. A broken taproot pushes up several new rosettes from the break. Lift them again and get more of the root each time.

How much seed does one plant produce? About 150 seeds per flower head, several heads a year, and it sets seed without needing pollination. Deadheading has to be thorough to make a difference.

Should I get rid of them in the lawn? That is a judgement rather than a rule. Dandelions in April are one of the best early pollen and nectar sources in Britain. Many gardeners now leave the lawn alone until June and keep the beds clean.

Can I eat it? All of it. Young leaves before flowering are best in salad, the flowers make wine, and the roasted root is a coffee substitute. Avoid roadsides, dog-walking routes and any ground that has been sprayed.

How do I stop it seeding into my gravel? Remove the flower heads before they open, and bag them rather than leaving them on the ground, because a picked head still ripens its seed.

Is this a dandelion or something similar? Dandelion has one unbranched hollow leafless stem per flower. Catsear, hawkbit and sowthistle all have branched or leafy stems.

What makes a lawn full of them? Thin worn compacted turf. Aerate it, feed it, raise the mowing height and thicken the sward, and dandelion establishes far less readily.

Does the milky sap matter? It stains skin and clothing and causes contact dermatitis in a few people. Wash it off.