Phelipanche spp.

broomrape

Europe, Asia, and Africa (centered on the Mediterranean)

Overview

Phelipanche spp. is a genus of about 40 species of holoparasitic flowering plants in the broomrape family, Orobanchaceae, native to Europe, Asia, and Africa and centered on the Mediterranean and temperate Eurasia. The plants lack chlorophyll and true foliage, drawing all their water and nutrients from the roots of host plants through a swollen attachment called a haustorium. Above ground they appear as erect, fleshy, pale stems 4-24 in (10-60 cm) tall, clothed in small brown scales rather than leaves and tipped with spikes of two-lipped, snapdragon-like flowers in blue, violet, lilac, or white. Each plant can set thousands of dust-like seeds that survive many years in the soil and germinate only when they sense chemical signals from a nearby host root. Phelipanche spp. was long included in the genus Orobanche spp., from which it is separated by floral and pollen characters. Several species, especially branched broomrape P. ramosa and P. aegyptiaca, are damaging agricultural parasites of crops such as tomato, tobacco, oilseed rape, and legumes, lowering yields where they take hold. P. ramosa is regulated as a noxious or quarantine weed in the United States, Australia, and other regions, and is the target of eradication programs.

Native Range

Phelipanche spp. is native to Europe, Asia, and Africa, with the greatest diversity around the Mediterranean Basin and across temperate and subtropical Eurasia. The plants occur wherever suitable host plants grow, in fields, grassland, scrub, and disturbed ground, and several species have spread as weeds far beyond their native range.

Suggested Uses

Phelipanche spp. has no horticultural or landscape use and is undesirable wherever crops are grown. It is studied in agriculture and plant science as a model parasitic weed and in research on host-parasite signaling. Records of its presence are used in quarantine and crop-protection monitoring.

How to Identify

Identify Phelipanche spp. by leafless, fleshy, pale to purplish stems that emerge directly from the soil over a host plant root, bearing brown scales in place of leaves. The stems end in spikes of two-lipped, blue to violet or white flowers, and branched broomrape P. ramosa differs from most Orobanche spp. in its branched stems and bluish blooms. The absence of green tissue and of any root system of its own marks it as a parasite.

Appearance

Size & Dimensions

Height4" - 2'

Width/Spread2" - 8"

Colors

Flower Colors

Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Spring Summer

Phelipanche spp. flowers mainly in spring and summer, as the parasitic shoots emerge and bloom alongside the growth of their host crop. Flowering stems appear above ground only briefly to set seed, then wither. In warm climates and on long-season hosts, emergence can continue over several months.

Detailed Descriptions

Flower Description

blue, violet, lilac, or white

Foliage Description

brown scales; no true leaves

Care & Maintenance

Care Guide

Phelipanche spp. is not grown as an ornamental and is treated as a parasitic weed wherever it appears. The seeds germinate only in response to chemicals released by host roots, after which the seedling attaches and lives entirely on the host. Because a single plant produces enormous numbers of long-lived seeds, infestations build quickly and persist in the soil for a decade or more. Management on farms relies on clean seed and equipment, resistant crop varieties, trap and catch crops that trigger suicidal germination, and soil treatments, rather than on chemical control alone. Hand-pulling emerged shoots before they seed reduces but rarely eliminates an infestation. The parasite weakens and stunts its host, lowering crop yields.

Pruning

Phelipanche spp. is not pruned or cultivated. Emerged flowering shoots are removed and destroyed before the seed ripens to limit spread, since each shoot can release thousands of seeds. The underground attachment on the host root usually remains and may send up further shoots.