Toothwort

How to recognise it

Growth habit

Perennial parasite without chlorophyll. Above ground there are only flower spikes of 8–30 cm, often in small groups; the rest of the plant lives underground.

Leaf

No green leaves. The stem carries a few pale, papery scales; underground, the rhizome is covered in thick, white, fleshy scale leaves that overlap like teeth.

Flower

Two-lipped tubular flowers of about 1.5 cm, creamy white to flesh-pink, sometimes tinged purple, with a bell-shaped, hairy calyx. They sit in a dense one-sided spike with a nodding tip. From March to May.

Fruit/Seed

An egg-shaped capsule with a few seeds. They only germinate next to the roots of a suitable host tree.

Stem

Thick, fleshy, white to pink and unbranched. After flowering it turns brown and by June it has withered completely.

Confusion with

Broomrapes flower in summer on herbaceous plants and have brownish or yellowish flowers all round the stem. Yellow bird’s-nest is yellowish and flowers in summer under beech and pine. Bird’s-nest orchid is a brown orchid of beech woods in May–June. Purple toothwort, a garden escape, has large purple flowers right at ground level.

Flowering: March–May

Why grow it?

• One of the first nectar sources in the spring woodland: bumblebee queens visit the flowers as early as March.
• A living textbook example of a plant without chlorophyll: it takes water, sugars and nutrients from the roots of its host tree.
• It usually does its host little harm: a hazel with toothwort carries on growing as normal.
• A typical plant of old, undisturbed woods and hedgerows with rich, moist soil; where it grows, the woodland floor has been left in peace for a long time.
• A surprising find in an old garden with hazels: if you have it, cherish it.

Toothwort: where does it grow best?

• In the wild: damp, rich deciduous woods, alder carr, woodland edges, sunken lanes, stream banks and old hedgerows, mostly on loam or chalky soil.
• Always near a host tree: usually hazel, but also alder, elm, poplar, hornbeam or beech.
• Part shade to shade under deciduous trees, in loose, humus-rich soil that never dries out.
• In the garden: only in an old, quiet hedgerow or woodland edge with hazels and a thick layer of leaf litter, where the soil is never dug.

Goes well with

• Hazel: The main host tree: no hazel, no toothwort.
• Wood anemone: Flowers at the same time in the same damp woodland.
• Moschatel: A small green spring flower of the same rich woodland soil.
• Oxlip: Yellow flowers next to the pale spikes in March–April.
• Yellow archangel: Takes over the flowering in April–May and keeps the ground covered.

Toothwort: when and how to plant it?

1. You cannot buy toothwort like an ordinary garden plant, because it cannot live without a host tree. So first plant a native hazel or alder in a moist, shady spot.
2. If it already grows in your garden or a neighbour’s, take a few ripe seeds in May–June and scatter them straight away close to the young roots of a hazel.
3. Scratch open the leaf litter, lay the seeds on the soil, cover them lightly with leaf mould and keep the spot moist.
4. Be patient: it takes many years before the first flower spike appears above ground, and it often does not work at all.
5. Leave the soil around the host tree alone: no digging, no raking and no clearing of fallen leaves.
6. Never dig up plants or rhizomes from the wild and do not take seed there: they do not survive being moved, and the sites are fragile.

Care

Watering

Not needed in moist woodland soil. In a very dry spring, give the host tree a good can of water now and then.

Feeding

Do not feed. A layer of its own fallen leaves is all it needs.

Leaf litter

Leave fallen leaves where they lie: they keep the soil cool, moist and rich in humus.

Peace and quiet

Do not walk on the spot in March–May and never dig around the host tree. Mark the place with a stick so you do not damage it for the rest of the year.

Host tree

You can coppice a hazel without worry: as long as the roots live, the toothwort lives too. Never grub out the host tree.

Tip: Mark the spot where you see toothwort flowering with a few twigs: for the rest of the year there is nothing to see, and this way you will not dig or plant there by accident.

Pruning and mowing

When: Not needed: after the seeds ripen in June, the stems wither by themselves.

How:

• Simply leave the withered stems where they are; they rot down into the leaf litter.
• Do not cut anything during flowering: the flower spikes are the only parts above ground.
• If you prune the host tree, do it in winter and leave the roots undisturbed.

Caution: Coppicing the hazel is fine, but never remove the shrub: without its host, toothwort dies.

Pruning calendar and basic rules

Propagation

Seed

In May–June, take ripe seeds from the capsules and scatter them straight away near the roots of a hazel or alder. They only germinate if the seedling touches a host root.

Rhizome

Underground, the plant slowly spreads along the roots of its host tree. In practice, moving it does not work.

Toothwort: how does it get through the winter?

Hardy to −30 °C.

• Nothing shows above ground in winter: the plant overwinters as a fleshy, scaly rhizome.
• As early as February, the first pale buds may push through the leaf litter.
• Fully hardy: the rhizome is protected in the woodland soil under a blanket of leaves.

Diseases and pests

• Slugs and snails: They sometimes eat the young, juicy flower spikes. In a natural spot with hedgehogs, thrushes and ground beetles the damage usually stays small.
• No flowers: It can live underground for years without flowering, or skip a year after a dry spring. Give it time.
• Lost host tree: If the hazel or alder is removed or dies, the toothwort disappears too. Protect the host tree.
• Trampling and digging: The stems snap easily and the rhizome lies close to the surface. Route the path around the spot.

Through the year

• February: The first pale buds may push through the leaf litter.
• March: Flower spikes appear. Bumblebee queens visit the flowers.
• April: Full flower. Do not trample.
• May: Last flowers; the fruits swell.
• June: Seeds ripen; the stems turn brown and wither.
• October: Leave fallen leaves under the host tree.
• December: Coppice the hazel if needed, without damaging the roots.

Did you know?

• The genus name Lathraea comes from the Greek lathraios, ‘hidden’: the plant lives almost entirely underground.
• The scale leaves contain small hollow chambers lined with glands. People once thought the plant used them to catch and digest tiny animals; we now know the glands mainly give off water.
• The name ‘toothwort’ refers to the white, tooth-like scales. Under the old doctrine of signatures, the plant was therefore believed to help against toothache.