Parietaria judaica (pellitory-of-the-wall)

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Parietaria spp.

pellitories

Urticaceae

Worldwide temperate and subtropical; center of diversity Mediterranean

Drought Tolerant

Native to North America

SunFull Sun – Part Shade – Full Shade

WaterLow · drought-tolerant

HardinessZones 5–10

Overview

Parietaria spp. is a genus of about 20 species of annual and perennial herbs in the nettle family (Urticaceae), native to temperate and warm regions worldwide. Unlike true nettles, the plants lack stinging hairs. Stems are weak, branched, and often reddish, sprawling or ascending 6–36 inches (15–90 cm), with alternate, entire, oval to lance-shaped leaves 0.5–3 inches (1–8 cm) long. Flowers are small, greenish, and clustered in the leaf axils, with male, female, and bisexual flowers mixed together. The flowers are wind-pollinated and release large amounts of airborne pollen, a major cause of hay fever in Mediterranean regions. Fruit is a tiny dry achene enclosed by the persistent calyx. Plants grow in cracks of walls, rubble, and disturbed ground, rooting in poor soil and shade. P. judaica and P. officinalis are widespread weeds, while several species are restricted to rocky native habitats. The long flowering season carries an extended pollen release from spring into fall.

Native Range

Native to temperate and subtropical regions across Europe, Asia, Africa, and the Americas, with the center of diversity around the Mediterranean. Grows on old walls, rock crevices, rubble, hedge banks, and shaded disturbed ground from sea level to about 5,000 feet (1,500 m).

Suggested Uses

Rarely cultivated, and grown mainly in historical herb and medicinal collections, where P. officinalis has a long record of folk use, spaced 12–18 inches (30–45 cm) apart. In most settings the plants appear as self-sown weeds rather than chosen plantings. The heavy pollen production limits any use near homes and seating areas.

How to Identify

Recognized by weak, often reddish branching stems, alternate untoothed oval leaves without stinging hairs, and clusters of small greenish flowers tucked in the leaf axils. Stems and leaves cling to clothing through tiny hooked hairs. The absence of stinging hairs separates Parietaria spp. from the true nettles (Urtica spp.).

Appearance

Size & Dimensions

Height6" - 3'

Width/Spread1' - 2'

Colors

Flower Colors

green

Foliage Colors

green

Bloom Information

Flowering extends over a long season, from spring through fall and nearly year-round in mild climates. The greenish flowers release pollen continuously over this period, peaking in late spring and summer. The extended flowering makes the pollen a prolonged source of seasonal allergy.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade SunFull Shade

Requires 2-8 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 8.0(Neutral)

357912

Soil Types

loam sand chalk rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grows in sun or shade and almost any well-drained soil, including the lime mortar of old walls and dry rubble, with low water once established. Plants are drought-tolerant and self-seed heavily, colonizing pavement cracks and neglected ground. As weeds they are hard to remove because stems break and roots resprout. Pollen causes hay fever and asthma in sensitive people during the long flowering season. Few pests or diseases affect them. Growth is rapid in spring, slowing in summer heat.

Pruning

No pruning is practiced on wild plants. Cutting or pulling stems before flowering reduces pollen and seed, though regrowth follows from the persistent root. Repeated removal over several seasons is needed to clear an area.