Burnet and Blue

Burnet: A most precious herb, the continual use of it preserves the body in health and the spirit in vigour.
Culpeper

Great burnet (Sanguisorba officianalis) is a stately denizen of our floodplain meadows – a larger cousin to the more diminutive salad burnet (Sanguisorba minor) that you might find in upland calcareous grasslands or as a pasture herb. Both have much to recommend them and cultivars are popular with gardeners and farmers alike.

Drawing of a Sanguisorba officianalis plant showing the aboveground parts and the deep root system. Blue butterflies are shown visiting the flowers.

The great burnet grows a metre tall and produces striking crimson lollipop flowerheads that nod gracefully in our hay meadows from June to September. They are actually a member of the rose family, though the resemblance isn’t obvious. They lack petals and the crimson heads are made up of the coloured sepals of small, clustered flowers.

The roots of great burnet can be as much as two metres deep and it spreads via underground rhizomes to form potentially vast clones that can be many decades old in undisturbed meadows. Those deep roots mean it can tolerate dry conditions but it is a signature species in wet lowland hay meadows where it is well adapted to tolerate the unpredictable cycles of flooding and drought. It recovers more quickly than grasses after flooding or hay cutting, rapidly producing a new canopy of young leaves.

Blue buddies

The great burnet is a principle food plant of the European large blue butterflies Phengaris nausithous and Phengaris teleius. These wily butterflies lay their eggs in the flower head of great burnet where the larvae can feed on the seeds before dropping to the ground and sending out a pheromone beacon to attract worker ants. The caterpillars are taken into the ants’ nest where they can feed on ant grubs and pupate in peace.

Great burnet is also an important nectar source for a wide range of UK insects, though its tall nodding flower heads make them tricky to photograph!

Guttation

One of my favourite things about an early morning floodplain meadow is how prettily the great burnet leaves exhibit the pearly phenomenon of guttation. This isn’t dew, which is moisture condensed from the atmosphere. Guttation happens at night when most plants have their stomata – the pores on the underside of their leaves – closed whilst they are not transpiring. If the soil is wet and evaporation is low, water that is taken up causes a slight pressure inside the plant. To balance this pressure, sap can be released via glands called hydathodes along the leaf tips and edges. The crenelated margins on burnet’s leaves mean these drops create a dainty bejewelled crown that is an early morning joy.

Herbal helper

As revealed by the quote at the top of this page, burnets have a long history of medicinal use. The name Sanguisorba is derived from ‘sanguine’, meaning blood, and ‘sorba’ meaning ‘absorb’. The roots and leaves have long been used to stem bleeding and cleanse the blood, whilst the flowers were once used to make a ‘burnip’ wine that was said to lift the spirits. Handily, the leaves contain soothing anti-inflammatory compounds that are useful for insect bites and burns – both common risks in a summer meadow. The leaves taste a bit like cucumber and can be a pleasant addition to salads or as a green tea for a dose of antioxidants and other beneficial plant compounds. I enjoy it blended with mint. So after a day out in the meadows you can brew yourself a refreshing cup and also use it, once cooled, to dab on any bites and sunburn that you didn’t manage to avoid. It’s even said to have anti-wrinkle properties!

Nutrition and hay

As one of the iconic species on our floodplain meadows, great burnet is an important component of the hay harvested there. As well as the health benefits already discussed, the tannins present in this plant have been shown to reduce methane production in ruminants. It’s antibiotic and anthelmintic compounds, along with the range of dietary minerals accessed from deep in the soil by the extensive root system, make this a useful plant for maintaining livestock health.

So if you or your livestock want to ‘preserve the body in health and the spirit in vigour’,don’t forget to give thanks to great burnet for its many gifts. But if foraging for it, make sure you do so responsibly and with permission and leave plenty for the invertebrates. Seed is readily available, so if you’re partial to a cup, why not grow some in your garden to enjoy these burnet benefits?