Hemp Broomrape
Orobanche ramosa
Broom-rape family (Orobanchaceae)
Addicted to hemp
Orobanche ramosa is a very rare species in the Netherlands. Since 1928 it was considered to be extinct until it reappeared in 2011 in the Utrecht Botanical Gardens. Where this little Red Listed plant suddenly appeared from is not clear but many individuals can be found every year in association with the hemp plants in the Thematic Garden – both of the varieties that are harvested for fibres and the medicinal hemp (Cannabis sativa).
It grows only near the hemp because Orobanche ramosa is parasitic on these plants and uses its roots to pierce the root system of its host to absorb water and nutrients. This is at the expense of the vitality of the host.
The hemp broomrape is an ‘addict’ because it also parasitizes tobacco plants. This little plant was therefore once considered an annoying weed in Dutch tobacco fields.
Themes
Crown jewel in the Utrecht Botanic Gardens.
Details
Description: | (hemi)-parasite, 15-50 cm. |
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Distributions: | West asia, north africa and southern and central europe. naturalised in other parts of europe, africa and north america |
Habitat: | Flourishes particularly on tabacco and hemp; on farmland, roadside verges and also in the sandy coastal regions. |
Year cycle: | Flowers only once (monocarpic annuals) |
Hardiness: | Colder than -4 f (very hardy) |
Flowering period: | Juli - oktober |
Flower color: | Purple |
Notes on flowers: | Amethyst-coloured flowers |
At its best: | Juli - oktober |