Yellow Loosestrifes
What are they?
This page covers a group of yellow-flowered plants in the primrose family (Primulaceae) with mostly five-petalled, star-like flowers. They vary from tall, clump-forming perennials with dense, upright flower spikes, to creeping ground huggers.
Where are they found?
Most of these species favour damp ground, either in woodland clearings that are seasonally flooded or in more permamently damp areas such as the margins of rivers, ditche and ponds. Some are introduced and might appear on roadsides or in urban areas, but even they would favour damp ground if they can find it.
Identification
The flowers are all rather similar, though sepal detail should be noted as subtle differences in these can help to separate some otherwise rather similar species. Growth style (whether upright or creeping) should be noted and leaf size and shape can be useful to note, also.
Yellow Loosestrife Lysimachia vulgaris
Native. Widespread in tall-herb fens and along the banks of rivers and permanent water courses. Most common In Broadland and the edges of Fenland. Flowers July to August. A fairly tall plant, to 1.5m in height, with an open, branched flower spike. The sepals have distinctive, orange margins which can still be seen around the seed capsules after the petals have dropped. Plants on roadside verges or near human habitation are more likely to be Dotted Loosestrife and the sepal margins are the best distinction between the two.
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Dotted Loosestrife Lysimachia punctata
Introduced from continental Europe as a garden ornamental and quite frequently found on roadsides and rough ground or planted by village ponds. Flowers July to September. A fairly tall plant, to 1m in height, with a dense, unbranched flower spike. The sepals do not have orange margins.
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Tufted Loosestrife Lysimachia thyrsiflora
Introduced as a garden ornamental with two records in our region involving plants of unknown origin. As with most yellow loosestrifes, this species favours damp ground. Flowers June to July. An upright plant with narrow leaves. The flowers have narrow, strap-like petals and are clustered in tight bundles in the leaf axils.
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Yellow Pimpernel Lysimachia nemorum
Native. Widespread in bare, open spots in woodland on damp ground, typically where the ground is kept clear by winter flooding. Flowers May to September. A low, trailing plant with star-shaped flowers that open flat and are carried on long, very slender stalks. Leaves clearly longer than broad and with pointed tips.
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Creeping-Jenny Lysimachia nummularia
Native in damp grassland and wet woodland but also occurs as an escape from cultivation in churchyards and a variety of disturbed habitats such as roadside verges and track sides. Flowers June to August. A low, trailing plant with flowers that are more cup-shaped and carried on stouter stalks than those of Yellow Pimpernel. Leaves more or less rounded, only slightly longer than broad.
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