Jeremy Bartlett's LET IT GROW blog

The wonder of plants and fungi.

Cowslip, Primula veris

Posted on 1 June, 2017 by Jeremy Bartlett1 November, 2018

Cowslip, Primula veris, at Noar Hill in Hampshire.

The Cowslip, Primula veris (a perennial in the family Primulaceae), is one of the delights of May. It flowers a few weeks later than its close relative, the Primrose, Primula vulgaris, which I wrote about in March 2012. Here in Norfolk, it is especially common on verges in parts of South Norfolk and you can see masses on the banks of the A11 Wymondham bypass (where it was deliberately planted). Nationally, the plant declined in the mid twentieth century as grasslands were ploughed up or “improved” with artificial fertilisers, but it is still quite widespread. The current and past distribution in the British Isles is shown in the Online Atlas of the British and Irish Flora. The online article “Biological Flora of the British Isles: Primula veris L.” by Brys and Jacquemyn has a European distribution map and describes the Cowslip’s ecology and biology in considerable detail. Cowslips are also found in western Asia.

In mid May we stayed on the outskirts of Selborne in Hampshire, just a short walk from Noar Hill, a beautiful area of chalk grassland and scrub famous for its flowers and butterflies. Cowslips thrive here and are the food plant of caterpillars of the scarce Duke of Burgundy butterfly. The butterfly is on the wing from mid April until late May and Noar Hill is one of its strongholds. The female butterfly is very particular when choosing where to lay her eggs, avoiding plants which are too small or too leggy. Only the lushest, partially shaded plants are chosen, on north facing slopes of chalk downland. In woodlands Primrose is used as a food plant instead. If you want to read more, I recommend “The Butterflies of Britain & Ireland” by Jeremy Thomas and Richard Lewington (British Wildlife Publishing, 2014) and “In Pursuit of Butterflies” by Matthew Oates (Bloomsbury, 2016). Alan Thornbury’s Hampshire Butterflies website is a valuable guide to Hampshire’s butterflies and their best sites, including Noar Hill. We were fortunate to see several Dukes within an hour of arriving in Selborne.

Duke of Burgundy

Cowslip flowers are a deeper shade of yellow than primroses and have an orange base. They are arranged in an umbel, which often droops to one side, and arise on one or more stems from a rosette of wrinkled, toothed leaves which look very similar to Primrose leaves. There are some good photos on the First Nature and NatureGate websites, but you’ll need to sniff a Cowslip flower to capture its lovely scent.

Cowslips often hybridise with Primroses to form the False Oxlip, which has pale yellow flowers (like a Primrose), arranged in an umbel at the top of a stem (like a Cowslip). They bear a passing resemblance to the much rarer Oxlip, Primula elatior, which is a very localised plant of ancient woodlands.

When Cowslips were more common they were picked and used in ceremonies, such as Cowslip Sunday at Lambley in Nottinghamshire but in “Flora Britannica” Richard Mabey reported that the plant became so scarce in the area that garden grown flowers had to be used.

The name “Cowslip” may derive from the old English for cow dung or from slippery ground churned up by cattle: the disturbance of the ground by pasture will certainly help the plant to spread by seed. Other names include Paigles, Peggles, Hey-flower, Tisty-tosties and Key Flower, Key of Heaven, Lady’s Keys, Firy Cups, Petty Mulleins, Crewel and Buckles.

Cowslip leaves are edible though “not that tasty”, as are the flowers. The Plants for a Future website also lists a range of medicinal properties for the plant.

Cowslips make a lovely garden flower, in a border or naturalised in a meadow or lawn. Here, they will self seed but are very unlikely to become a nuisance. They like sun or partial shade – in deeper shade they will grow without flowering. They can be raised from seed, but I usually buy in plants and I let them do their own self seeding.

If you visit Selborne, I can recommend Gilbert White’s House – we spent a rainy morning there. The pub does good food but the roads are ridiculously busy with traffic, so we hardly did any cycling.

Green Alkanet, Pentaglottis sempervirens

Posted on 27 April, 2017 by Jeremy Bartlett28 April, 2017

Male Orange Tip butterfly on Green Alkanet

Although the past week has been cold and showery, we have had a very sunny and dry spring, with a lot of warm sunshine. Butterflies, bees and hoverflies have loved this weather and we have had many new sightings, on Rose ‘Canary Bird’, dandelions and perennial wallflowers in our back garden and, a short walk away, in Earlham Cemetery.

A star attraction in Earlham Cemetery has been Green Alkanet, Pentaglottis sempervirens. It is a pretty plant on its own, but it becomes more interesting when its flowers are visited by numerous insects.

Green Alkanet is native to south-western Europe and was introduced into British gardens before 1700 and made its first recorded escape into the wild in 1724. It is still increasing its range here, and now occurs in many parts of the British Isles.

In ‘Flora Britannica‘, Richard Mabey describes Green Alkanet as “a pert, bristly, medium-sized perennial”. The plant dies down in late summer but comes into leaf during the winter or very early spring – hence the scientific name sempervirens (“always alive”, or “evergreen”) and the “Green” part of the English name. The word “alkanet” comes from the Arabic word for henna, via Mediaeval Latin, Old Spanish and Middle English. Pentaglottis is from Greek, meaning “five tongues”, which presumably refers to the flower petals.

The leaves of Green Alkanet are fairly similar to Comfrey but are rougher and more bristly with white spots. By April or early May the plant has elongated and produced pink buds which open to beautiful borage-blue flowers with a white eye, which look rather like supersized Forget-me-nots. The resemblance of Green Alkanet to Comfrey, Forget-me-nots and Borage is not co-incidental: these are all members of the Borage family, the Boraginaceae.

It is not surprising that Green Alkanet is doing well. It isn’t fond of acid soils but it will tolerate shade as well as sunshine. Although it often grows in damp places, it is also happy on our local allotment site in sandy loam. It has a deep tap root which is hard to pull up and it is easy to leave pieces behind, which will keep growing. The plant also spreads by seed. Many gardens in the Unthank Road and Earlham Road area of Norwich are full of Green Alkanet and it was a serious weed in the Belvedere Centre garden. The RHS website recommends various strategies to get rid of Green Alkanet but I would urge you to dig up the roots and to stop the plant from seeding, rather than poison your garden with glyphosate. You can put the leaves on the compost heap, but don’t include the roots as they are likely to regrow. Alys Fowler suggests making a weed soup out of it to feed plants. Like comfrey tea, it will smell bad, but act as a great plant food. Wear gloves when handling the leaves, as the coarse hairs can cause a rash, due to structures known as cystoliths made of silicon dioxide and calcium carbonate.

Green Alkanet flowers are edible but rather tasteless and can be used to decorate salads, in the same way as Borage flowers. The plant may have been introduced for a red dye in its roots, although it may have been confused with the similarly named Alkanet, Anchusa officinalis. Clive Stace and Michael Crawley in “Alien Plants” think “it is a bit of a mystery why this species should be grown at all”.

But I think there is a good reason for liking and growing this plant: its wildlife value. If you have space, or in a wild area like Earlham Cemetery, Green Alkanet comes into its own. Its leaves are used by at least two species of leaf-mining flies (Agromyza sp.) and a micro moth (Coleophora pennella). It is also one of the foodplants of the Scarlet Tiger moth.

In Earlham Cemetery, the flowers are attracting Orange Tip and Green-veined White butterflies, hoverflies such as Rhingia campestris and solitary bees such as the Common Mourning Bee, Melecta albifrons and Gooden’s Nomad, Nomada goodeniana.

Scarlet Tiger moth at Hestercombe Gardens, Somerset.

Gooden’s Nomad Bee, Nomada goodeniana, on Green Alkanet in Earlham Cemetery.

Hoverfly Rhingia campestris on Green Alkanet in Earlham Cemetery

Canary Bird Rose, Rosa xanthina ‘Canary Bird’

Posted on 26 April, 2017 by Jeremy Bartlett1 November, 2018

Rosa xanthina ‘Canary Bird’ in our garden.

One of the joys of spring, in our garden and elsewhere, is the Canary Bird Rose, Rosa xanthina ‘Canary Bird’. It was one of my Dad’s favourite roses and we planted a specimen four years ago in our own back garden.

Rosa xanthina ‘Canary Bird’ is a cultivated form of the Manchu rose, Rosa xanthina, which is a wild shrub rose native to central China, where it grows in scrubby areas and on open hillsides. It usually has an upright, arching growth habit and will grow from two to three metres (six to nine feet) tall and spread to become about three metres wide. Its stems are reddish and have reddish-brown thorns with delicate mid-green leaves. Rosa xanthina has semi-double flowers and R. xanthina ‘Canary Bird’ has the same growth habit but its flowers are single and more open.

‘Canary Bird’ is one of the earliest roses to flower, usually in late April and early May, although ours started to bloom by mid April this year. The flowers have a delicate, musky scent. Our specimen bloomed in its first year but it has been more spectacular every year, as it has developed a bigger framework of branches. Sometimes the rose can have a second flush of flowers later in the year, but I haven’t seen this yet.

Rosa xanthina ‘Canary Bird’ is very hardy and can cope with quite dry soils, provided they contain some organic matter. It will grow in a sunny or partly shaded spot. Ours is in an east-facing border in sandy loam and is in sun from late morning to late afternoon during the summer. Although the RHS website lists a number of possible pests and diseases, species roses such as ‘Canary Bird’ are generally trouble-free, unlike sickly Hybrid Tea thoroughbreds. This makes it an ideal candidate for an organic garden.

‘Canary Bird’ is easy to prune and can be cut into an informal hedge where its thorniness will act as a deterrent to intruders. It is sometimes used in municipal plantings and there is a fine stand of it next to the Canaries (Norwich City) football ground here in Norwich.

It is hardly surprising that Rosa xanthina ‘Canary Bird’ has been praised in the gardening press. It was The Guardian’s Plant of the Week in March 2012 and featured in Alan Titchmarsh’s gardening column in the Express in April 2016.

But I have left the best thing about ‘Canary Bird’ until last: it is great for wildlife. A mature specimen will provide nesting places for birds but it is the flowers that are proving to be very popular with insects in our garden, including hoverflies, and bees such as the delightfully named Chocolate Mining Bee, Andrena scotica.

A female Chocolate Mining Bee, Andrena scotica, on a ‘Canary Bird’ flower.