Heliotropes & Butterburs
What are they?
This is a small but interesting group of plants in the daisy family (Asteraceae). These plants typically send up their flower spikes from below ground before the leaves, allowing the flowers to be more readily found by early-season insects. The leaves push up as the flowers pass their peak and continue to grow and expand, like little rhubarb leaves, well into the growing season. Most spread by means of creeping root systems to form extensive patches and the introduced species can be quite invasive, smothering out other plants with ease. Individual plants in this genus are functionally either male or female; each plant bears flowers that have both sexual parts of the flower pfresent, but only one sex being properly developed and functional, thus being effectively male or female plants. In the case of most species, seed-set is rare or unknown, with plants spreading vegetatively from pieces of broken root.
Where are they found?
Most members of this group prefer rich, damp soil along ditches and the edges of wetlands, as well as on road verges.
Identification
All species have their small, five-petalled flowers carried in clusters on branched flower spikes and appearing before the leaves are fully developed. To tell them apart, note the colour of the flowers, the overall shape of the flower spike and the presence or absence of leafy bracts in the flower spike.
Winter Heliotrope Petasites pyrenaicus
Introduced from southern Europe as a garden ornamental. A highly invasive species that is becoming ever more common due to the dumping of plants after they have become out of control in gardens. Widespread on road verges and rough ground. Odd flowers appear from late November or early December, but the main flowering period is January to February. Grows to form dominant and often extensive patches. Flowers all male in our region, highly fragrant, with the scent of almond marzipan. Leaves relatively small, growing to 20cm in diameter.
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Common Butterbur Petasites hybridus
Native in the UK, but all East Anglian plants are male, suggesting that our population may have arisen from introduced garden plants. Flowers March to May. Flower spikes short stalked, forming a densely packed, cypindrical spike. Leaves large, rhubarb like, growing to 90cm in diameter.
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Giant Butterbur Petasites japonicus
Introduced as a garden ornamental and persistent in a handful of places in damp soil in Norfolk and Suffolk. Flowers March to April. Flowers creamy white, the spikes bearing prominent, pale green, bracts. Leaves large and rhubarb-like, developing after the flowers are gone and reaching up to 100cm in diameter.
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