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American Independence day in the rock garden

July 11, 2024
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A few American plants would seem appropriate for the 4 July celebrations

I’m often sure of facts until I start to do some research. Then I get surprised. There are some historians who believe Independence day should be 2 July. This was the date that the 13 states declared Independence, but it was on 4 July that John Hancock signed the declaration document. It was a month later, on 2 August that the other state officials all signed it. What has that to do with gardening? Absolutely nothing.

It does show that when you think you know something there are always a few facts that prove you wrong. I will use the accepted Independence date as an excuse to feature a few of the American plants I saw at Wisley, to pay homage to the anniversary of this historical event. All the pictures featured were taken between 4-8 July.

Out on the main rock garden the American theme begins

Oenothera fruticosa subsp. glauca is from eastern North America. The first of two evening primroses. The genus name is from the Greek I – wine and thera – pursuing or imbibing. The Romans believed that the roots of one species were used as an incentive to drinking. I personally have never suffered from any infliction that put me off drinking wine. The specific epithet is from the Latin for shrubby and for the subspecies – having grey green leaves.

Was Homer Simpson a gardener?

Oenothera macrocarpa is the Missouri evening primrose. Another of its common names is the Ozark sundrops. Ozark is a town near Springfield, Missouri. Had Matt Groening’s animated series ”The Simpsons” been created earlier, they might have been known as the Springfield sundrops. The specific epithet is from the Latin for large fruits.

Gladiolus ‘Atom’ is in the primulinus nanus hybrid group. It was raised and named in 1946 in the USA to mark the start of the atomic age. It grows to 90cm tall.

Gladiolus 'Atom'

Gladiolus 'Atom'

Wisley lets you go around the world in 80 minutes rather than 80 days

Leaving the American plants for a while, we can do a quick tour around many other countries, starting with three potentillas. Potentilla nepalensis, the Nepal cinquefoil, is found at 2100 to 2700m in Pakistan and central Nepal. The genus name is from the Latin potens – powerful, some species having strong medicinal properties. The specific epithet is from the Latin – of Nepal. It grows to 90cm.

Potentilla x tonguei AGM is a hybrid introduced in the 1960’s. It has apricot flowers with a red eye and blooms from mid-spring until late summer. It was named for William Tongue who was a horticulturalist at the Royal Botanic Garden Edinburgh who grew this plant.

Potentilla fruticosa var. albicans can be from North America to northern Europe, the Alps and Pyrenees all the way to western Asia. The specific epithet is from the Latin for shrubby and the variety again from the Latin for whitish.

Sedum album ‘Coral Carpet’ is a very common plant but one I like. The new growth is salmon-orange (coral), turning green and then red by winter. The genus name is from the Latin sedeo – to sit, as it sits or sprawls over rocks. The specific epithet is from the Latin for turning white.

My other car is a Bugatti (I wish)

Eryngium bourgatii is one of the sea hollies. I might never be able to afford the car but I can always take consolation that I can afford the plant. The genus name is the Greek name for one of the thistles with spiny-toothed leaves. The specific epithet is to honour a French medical doctor, Dr Bourgat. He collected plants in the Pyrenees in 1776 and 1777. It grows in Andorra, France, Spain, Morocco and Turkey. It has nothing to do with Ettore Bugatti (1881 – 1947) the Italian born, French car designer.

Primula florindae was collected by Frank Kingdon-Ward OBE, VMH, VMM (1885 – 1958) who named it for his wife Florinda. Its common name is the giant cowslip, Tibetan or Himalayan cowslip. It comes from southeastern Tibet. I think it is very appropriate for a famous plant collector to marry a flower.

Platycodon grandiflorus pumilus hails from East Asia including China, Korea, Japan and the far east of Russia. It grows to 60cm tall and will thrive in sun or part shade. It’s common name is the Chinese balloon flower. The genus name comes from the Greek platys – broad and kodon – a bell. The specific epithet comes from the Latin for large flowered and low, small or dwarf. It is easily grown from seed and will thrive in well drained slightly acidic soil. The roots contain saponins.

Another Chinese plant in flower with an English connection

Ceratostigma willmottiana ‘Forest Blue’, the hardy plumbago, is said to flower from late summer to early autumn (August to October) but is already in flower at the beginning of July. This Chinese species, grows to 60cm tall, and thrives in sandy or loamy soils, dry or moist, full sun or partial shade. It will not grow in full shade. Prune it hard in spring, as it flowers on the current year’s growth. The genus name is from the Greek keras – a horn – referring to the horn like branches of the stigma. The specific epithet was named in honour of Miss Ellen Ann Willmott FLS, VMH (1858 – 1934) an English horticulturist and plant introducer. She has an incredible life story.

Why would you want a goblin in the garden?

Goblins are evil, mischievous or even malicious spirits, so why would you welcome them into a garden? Veronica spicata ‘Pink Goblin’ AGM, the spiked speedwell, would be welcomed into mine. It can be found growing widely across Europe and Asia. If it seeds about too much I might change my mind about offering it a home. I’m sure it will be very well behaved. The specific epithet is from the Latin for spiked with reference to the inflorescence.

I keep expressing surprise at seeing rhododendrons still in flower. This week was no exception. Rhododendron nakaharae ‘Mount Seven Stars’ has flower buds that are still to open. It will only be 30cm high after 10 years, making it ideal for a small rock garden. Seeds were collected by Mr. C.S. Kuo in 1968, on Mount Seven Star in Taiwan. This cultivar was selected as an excellent dwarf form.

Pincushions are not only practicable but can be beautiful

Scabiosa cretica is a woody perennial known as the Cretan pincushion flower. Some sources of information state it’s tender or half-hardy to H3 ( 0 to -5C) but at Wisley it’s survived H4 (-5C to -10C) in recent years. It has grown to 1m in height and is not pruned other than to remove the dead flower heads. The specific epithet reflects its origin of Crete and the Balearic Islands. Seedlings have been recovered from below it and planted in other parts of the Rock garden at Wisley.

Another Greek endemic in flower now is Pterocephalus pterocephala, the Mount Parnassos scabious.


Astilbe ‘Montgomery’ is a japonica hybrid, growing to between 30 – 70cm. It has glossy green leaves.

The next hybrid was created by George Arends (1862 – 1952) who was a German nurseryman from Ronsdorf. He raised 74 astilbe hybrids as well as many other hybrids in different genera. His crosses involved a mix of Aa. chinensis, thunbergii and simplicifolia in various combinations.

Astilbe ‘Bronce Elegans’ AGM flowers from July to September. Its flowers are described as salmon pink and the new foliage has bronze tinges. It was given an AM in the RHS trials in 1970 and AGM in 1992. It was a seedling or sport of A. simplicifolia ‘Elegans’.

In the main crevice garden a few more American plants are in flower

Scutellaria suffrutescens ‘Texas Rose’ is known as the Mexican skullcap. It is found in Mexico but also parts of Texas, hence the cultivar name. The genus name is from the Latin scutella – a dish, alluding to the shape of the persistent calyx. The specific epithet is also from the Latin for having a woody base. The reference to skullcap is the shape of the seeds that resemble military helmets worn in the middle ages.

Some plants look good enough to eat

Abronia latiflora comes from the west coast of North America, from southern California to British Columbia. Its common name is the coastal sand verbena. It plays an important role in stabilising sand dunes as it has long fleshy roots. Traditionally the Chinook people ate them. Other root vegetables are now available to help you get your five a day. The genus name is from the Greek abros – delicate, referring to the membranous envelope that encloses the flowers. The specific epithet is from the Latin for broad leaved.

It’s not all about American plants

Teucrium chamaedrys is known as the wall germander. It grows in Mediterranean regions, north Africa and the Middle East. The genus name comes from the name of a Trojan prince, Teuchra. He used one of the species for medicinal purposes. The specific epithet is from the Latin for the old name for Germander.

Satureja montana has white, pink or pale lavender flowers. Its common name is winter savoury. Shakespeare mentions it in The Winter’s Tale. It has a salty or peppery flavour when used in cooking. It grows in southern Europe, the Mediterranean and Africa, preferring calcareous or alkaline soils. The genus name is from the Latin for savoury, the specific epithet from the Latin for from the mountains.

A couple of plants from the Alpine Display House

Knowing how much effort the team puts in to ensure a plentiful display, I feel a little mean in selecting just a couple of plants from the display house for this diary. The first is another American endemic (from California) Calochortus clavatus var. clavatus. The genus name is from the Greek kalos – beautiful and chortus – grass. Its common name is the clubhair Mariposa lily. The specific epithet is from the Latin for decorated or furnished with nails or studs.

Campanula sartorii can be found growing in the mountains of Greece. The flowers come white to pale pink. The specific epithet is to honour Joseph Sartori (1809 – 1880) a German / Greek apothecary and botanist who worked in Greece.

In the cushion house two Americans: one north, one south

Eriogonum flavum var. flavum hails from North America, the alpine golden buckwheat. The genus name is from the Greek erion – wool and gonu – a joint; the joints of the stems being downy. The specific epithet is from the Latin for yellowish and it certainly is yellow.

The second plant comes from Argentina. It used to be in the verbena family. It is now called Junellia succulentifolia. The flowers can also be lilac or pale blue as well as white. It is a shrubby, dry steppe species, growing at 400 – 1000m. No prizes for working out that the specific epithet is Latin for fleshy leaved. The flowers have a lovely scent.

Julia has been busy making two videos for the RHS YouTube channel

The last link I featured took you to Jess’s video on snowdrops. The two links below take you to videos that feature Julia and some of her favourite plants in the fern glade. They are only three minutes in length. As well as the plants featured there are some nice views of the fern glade, taken with a video drone camera. I do hope the RHS will produce more of these videos.

The first video is: Top 5 ferns of RHS Wisley.

The second is: Spring perennials for a shady spot.

Project updates in early July

The small additional crevice area that was shown during construction has now been planted up. In the final stage top dressing will be added.

Work on the bonsai walk continues

The replacement of the gravel along the bonsai walk has progressed in the last couple of weeks with just one small area left to do. I say small, but there is another four tonnes of gravel to lay. Twenty four tonnes will have been used in total.

Pinus parviflora ‘Tenysa-kazu’ is a Japanese white pine that has golden variegation. It has been planted in the bonsai walk and will be cloud pruned once it has grown a little.

Image of Mr and Mrs Hamish Sinclair Mr and Mrs Hamish Sinclair