Tiny bright-blue flowers with two large veined wings, above a rosette of oval leaves at the base, in short chalk turf in May
Chalk milkwort, Polygala calcarea.
Nature · Wildflowers & flowers
Chalk milkwort
Native · flowers May–Jun · old chalk and limestone grassland, southern England
Polygala calcarea — Polygalaceae
Chalk milkwort is a small, tufted, bright-blue relative of the common milkwort, confined to old, short chalk and limestone turf in southern England. Botanists treat it as one of the indicator species of chalk grassland with a long, unbroken history. It is best told from common milkwort by the rosette of larger leaves at the base of the stems.
How to spot them
- ▸Bright blue (rarely white or pink) flowers, each with two large petal-like inner sepals, the 'wings', whose veins branch and form a network at the tip
- ▸A distinct rosette of larger, oval leaves at the base of the flowering stems, with smaller leaves alternate up the stem
- ▸Low, tufted plant only 5–15 cm tall, in short chalk and limestone turf
- ▸Flowers in racemes of about 6–20 from May into June
- ▸Look-alike: common milkwort (Polygala vulgaris) lacks the basal rosette, has stem leaves that are alternate all the way down, and varies from blue to pink and white; heath milkwort has opposite lower leaves and grows on acid ground. The rosette on chalk is the clue
How to know it
Its larger basal rosette is the chief feature separating it from its commoner relative, which has no rosette and leaves alternating up the stem
The relative is common milkwort; this is chalk milkwort.
It is one of the plants that indicate chalk grassland with a long unbroken history, alongside horseshoe vetch, dropwort, common rock-rose and round-headed rampion
Chalk milkwort.
The family name derives from the Greek for 'much milk', because cows fed on these plants were believed to give more
Polygala — milkworts.
Members of this genus were traditionally picked for Rogation processions, in the days before Ascension, earning the name 'rogation flower'
Milkworts, including chalk milkwort.
A rarer chalk-and-limestone cousin, the dwarf species, has bluish or pink flowers and is found mainly in Kent, Yorkshire and Cumbria
That cousin is dwarf milkwort; this is chalk milkwort.
Quick-fire facts
- •Native perennial of short, old, calcareous grassland, mainly in southern and south-eastern England
- •Family Polygalaceae; Polygala is from the Greek for 'much milk'
- •One of the indicator species of chalk grassland with a long history, thought to survive only in turf undisturbed for a very long time
- •The blue 'petals' of a milkwort are in fact two enlarged inner sepals, called wings, that shelter the small true flower
- •Separated from common milkwort by the leaf rosette at the base of the flowering stem
- •Common milkwort flowers May to September in blue, pink or white (Wildlife Trusts); dwarf milkwort is a rare plant of chalk and limestone in Kent, Yorkshire and Cumbria
- •Habitat is threatened by ploughing, fertiliser, and by scrub taking over unmanaged grassland
Drill it — 7 cards
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Sources
- JNCC — Dry grasslands and scrublands on chalk or limestone (H6210)
- The Wildlife Trusts — Common milkwort
- The Wildlife Trusts — Dwarf milkwort