Rumex longifolius

Rumex longifolius

Plant Family

Polygonaceae

Botanical Description

Northern Dock is a perennial herb growing 60-120 cm tall with large, lance-shaped leaves up to 40 cm long. Lower leaves have wavy margins. Tall spikes of greenish to reddish-brown flowers appear in summer, followed by winged fruits.

Cautions

Contains oxalic acid - avoid in kidney stones, gout, or rheumatism. Not suitable during pregnancy. Large amounts may cause digestive upset.

Habitat

Roadsides, fields, waste ground, riverbanks, and disturbed areas.

Harvest Instructions

Roots harvested in autumn or early spring. Young leaves can be harvested in spring before flowering.

Geographic Distribution

Native to northern Europe and Asia. Common throughout Iceland and Scandinavia.

Growth Conditions

Tolerates various soil types. Prefers moist, nitrogen-rich soil. Full sun to partial shade.

Plant Size

60-120 cm

Pests & Diseases

Generally pest resistant. May be affected by leaf beetles.

Effects on the Body

Blood purifying, supports liver function, mild laxative effect. Traditionally used for skin conditions, constipation, and as a spring tonic.

Active Constituents

Anthraquinones (emodin, chrysophanol), tannins, oxalic acid, iron, vitamin C.

Safety Information

Dosage

Root decoction: 1-2 teaspoons dried root simmered in water for 15 minutes, 1-2 cups daily. Tincture: 2-4 ml three times daily.

Culinary Use

Young leaves can be eaten cooked like spinach but should be used sparingly due to oxalic acid. Often mixed with other greens.

Folklore & Historical Use

Traditional remedy for skin diseases and blood purification in Nordic countries. Root was used to make a yellow dye.

Scientific Research

Limited clinical research specific to this species. Related Rumex species contain anthraquinones with documented laxative effects. Contains oxalic acid, tannins, and vitamin C.