Sid Valley Herbaceous Flower Survey 2021, July Update

This is the July 2021  update to the year-long survey of the valley’s herbaceous plants being carried out by volunteers with the Sid Valley Biodiversity Group. 

Reports from previous months can be found on the Group’s website https://sidvalleybiodiversity.org/ and all of the group’s records can be found on the iNaturalist database at https://www.inaturalist.org/projects/umbrella-to-sidmouth-hedgerow-herbaceous.

The SVBG volunteers are recording which herbaceous plants are in flower in the valley each month.  This is a citizen scientist project with volunteers from the group noting which flowers they see when out walking around the town and in the countryside.  The survey includes repeat visits to a number of sites around the valley which have been selected to represent a range of habitats.  Usually, the sites include the beach, hedgerows, heath, and open grassland, and are spread to cover the valley from north to south and east to west.  In July the group did not manage to arrange surveys of the sites to the north of Sidbury.  This is unfortunate because some of the wet and uncultivated habitats at the head of the valley are known to be home to some species not found in the south of the valley.  It is hoped that the northern half of the valley will be the subject of a new and more comprehensive survey in 2022.

Since the start of spring, the number of recorded species has grown steadily, and we now have 363 on the list from Agrimony to Yorkshire Fog.  July set another record for the survey with 236 species, 80 recorded for the first time.  See Appendix 1 for July’s recorded species with the newcomers highlighted in green, and Appendix 2 for the species recorded previously but not seen this month.  Some of the species in Appendix 2 are early flowering ones such as Snowdrops, Lesser Celandine and Winter Heliotrope and have definitely finished flowering, others could be continuing to flower, but we just did not find them.

Dandelion flowers have been recorded every month so far and that is very important to the valley’s biodiversity because they supply nectar and pollen to so many insects.  There are a dozen flowers that have been recorded every month so far including Common Daisies in verges and lawns, the daisy-like Mexican Fleabane, as well as Ivy-leaved Toadflax growing in the cracks on so many walls around the town, Periwinkle, Red Campion and Herb Robert in the countryside hedgerows, and Smooth Sow Thistle which keeps a foothold in many sites. The ever-present species are highlighted in peach on the list.

Last month we said that the grasses, rushes, and sedges had been left out of this year’s survey because the volunteers did not yet have the knowledge to distinguish these tricky groups and training was earmarked for next year.  Fortunately, a small number of the volunteers have had their identification skills upgraded and some of the grasses are now in the record.  Grasses tend to have descriptive common names.  There are four common members of the Poa genus of Meadow-grass, Rough and Smooth are obvious, you will find Wood Meadow-grass in the riverside woods by Margaret’s Meadow in The Byes, and Annual Meadow-grass is short-lived but produces seeds and new plants across much of the year.  If you turn the one-sided flower spike of Crested Dog’s-tail and wag it, it looks rather like the tail of a golden retriever.  The three-pronged flower spike of Cock’s Foot looks like a chicken’s foot if you turn it upside down and stand it on the ground.  False Oat-grass looks rather like a thin agricultural Oat, but the seeds will make very poor porridge.  Timothy-grass is supposed to be named after the agriculturalist Timothy Hanson who promoted it as a good hay crop species in the 19^th century, but it is also called Meadow Cat’s-tail because the flower spike stands like the tail of a happy cat.

Earlier in the year, March was the real turning point of spring when the number of species in flower took a leap forward.  As we hit high summer, July sees a different turning point.  Although the number of species in flower has continued to climb, observers have noted that many of the species seen in March to June now have more seed heads than new flowers.  

That is not the end for our wildflowers, we expect to see plenty of flowers continuing into the autumn.  There has been much publicity about reduced mowing regimes to give the wildflowers in our grassland a chance to feed insects.  Now the seeds take the stage.  They will be needed for next year’s flowers, but they are also a vital food source for so many animal species that are preparing for winter.  Perhaps one of the most charming seed-eaters are the Goldfinches.  With their red faces and yellow wing flashes, these beautiful birds look like they would be at home in a tropical rainforest, but there is a small flock that visit the bank beside the Croquet club in Station Road most afternoons to feed on the Sticky Mouse-ear seeds.  Perhaps the same flock, Goldfinches make regular visits to the Thistles growing in the park of Knowle further up Station Road.  Thistle’s downy seeds are a particular favourite of these birds. 

May was the Speedwell month when the volunteers found nine different species of these tiny blue four-petalled flowers around the valley.  In July it was the time for the pink four-petalled flowers of the Willowherbs.  The volunteers have recorded eight of the thirteen Willowherbs that can be found in Britain.  

As with so many of the extensive groups, Willowherbs can be difficult to tell apart and the volunteers had to use a magnifying glass and an identification key for some.  To give you an idea of the difficulty, the first step is to look inside the flower with a magnifying glass to decide if the tiny stigma is ‘knob-shaped or four-lobed’.  If it is knob-shaped, the next question asks whether or not the upper part of the stem has numerous tiny hairs.  If it has, then it is the introduced species American Willowherb, if not, the questions go on, asking the observer to look for square stems, ridged stems, are the leaves opposite or alternate, and so on.  

Not all the Willowherbs are that difficult.  As the name suggests, Great Willowherb is one of the largest at nearly 2m tall and has flowers up to 25mm across with a 4-lobed stigma that is easy to see.  Rosebay Willowherb is nearly as tall and has a distinctive spiral spike of flowers.  It specialises in colonisation of disturbed ground such as newly cleared forestry land and it became well-known as Fireweed on blitzed bombsites in WWII.  

The name Willowherb probably comes from the fluffy seeds which, like those of Willow trees, explode from the seed pods that split open when ripe.  The seeds are carried on the wind, and you will find Willowherbs clinging on in many niches such as the cracks at the base of roadside walls.

The yellow composite flower heads of the Dandelions continue to feed the bees and butterflies and they have been joined by several cousins including the Hawkbits and Tansy.  Tansy is the sole food plant of the Tansy Beetle, a large, iridescent green beetle, but you will not see one in Sidmouth.  The beetles are almost extinct in the UK, restricted to a small colony in Yorkshire and another in the Norfolk Broads.  

Tansy Beetles show how difficult it can be to conserve endangered species.  Small, isolated populations run the risk of decline because of inbreeding.  Conservationists tried to strengthen the gene pool of the Norfolk colony by importing Yorkshire beetles, but the project failed. The two colonies had developed different egg laying habits and the Yorkshire beetles laid their eggs at a depth in the Broads ground that flooded in winter and the eggs were drowned.  This is why it is so important to establish and maintain green corridors that allow various populations to mix naturally.  Every uncut verge and patch of garden that is left for wildflowers to develop can be a steppingstone to keep populations genetically healthy.  

A controversial member of the Dandelion family is Ragwort.  If you have horses, then you don’t want Ragwort in their field nor in their hay because it is poisonous to them and it should be cleared.  Sadly, many people apply the same principal to Ragwort even when it is growing where it can do no harm.  Ragwort flowers are used as a food source by many insects, but the leaves and flowers are the sole food source of Cinnabar Moth caterpillars.  Cinnabar Moths are beautiful, metallic blue moths and their caterpillars have vivid black and yellow stripes.  This is warning colouration because, as they feed exclusively on Ragwort, the caterpillars themselves are poisonous.  If you have a healthy population of Cinnabar Moths, their caterpillars will keep the Ragwort under control because they really do strip the plant bare.  Cinnabar Moths are in decline because so many people uproot the Ragwort before the caterpillars can complete their life cycle and that means the Ragwort gets out of control.  If you don’t have horses, then please leave some of the Ragwort for the caterpillars.

Bindweed is another plant with a descriptive common name, it binds around anything and everything and it is a serious weed in gardens, but it is a gem in the wild because it is a rich food source for many insects, and the large bell-shaped flowers are particularly easy for Bumble Bees to exploit.  The pale pink flowers of Field Bindweed have been showing in all sorts of places since early June but now the hedgerows are decked with the larger white flowers of Hedge Bindweed and Large Bindweed.  These two species are very similar, the distinguishing is not size but the green bracts at the base of the flower.  Those on Hedge Bindweed clasp the flower tightly but the Large Bindweed flower has two bracts that puff out like a pair of eighties padded shoulders.  Sea Bindweed is about the same size as Field Bindweed and you would expect to find it in Sidmouth, but it has escaped observation so far.  If you see a small pink bindweed with kidney-shaped leaves rather than the spearhead shaped leaves of the very common Field Bindweed, please let us know.

Even the river comes into flower in July.  Long strings of River Water-Crowfoot, a cousin of the Buttercup, can be seen in the shallower parts of the river and the white flowers are lifted above the surface to allow pollination by insects.  The same flowers are in the foreground of John Everett Millais’ tragic painting of Ophelia drowning herself because she has been spurned by Hamlet.  The extensive growth in the Sid is possibly almost as tragic.  It is a sign of nutrient rich water, possibly run-off from farmer’s fields, but also discharges from septic tanks at the head of the valley polluting the river with nitrates.

As we go into August, seed production will be in full swing, so please allow the process to complete before you cut your wildflower patches.  The council teams will be cutting the growth that some people find unattractive but remember that the cut sward needs to be left for a few days to allow the seeds to drop to the soil surface and then the sward should be removed to reduce the nutrient levels in the soil.  This will help to keep the rank grasses in check and encourage even more wildflowers next year.

Ed Dolphin