It’s 8.30pm. I am sitting at the table looking out onto my garden. The sun has set and dusk is blurring the outlines of the plants. The deeper shades of green are the first to blend into the gloom, along with the maroon leaves of the Heuchera “Palace Purple’. The greenish yellow foliage of the Sorbaria sorbifolia ‘Sem’ maintains its brightening effect for a little longer before receding into its corner. But two plants gleam through the gathering darkness due to their white flowers.
in the foreground is Hesperis matronalis var. albiflora. Held about a metre above the ground in plump racemes, the four petalled flowers resemble those of the white form of Honesty (Lunaria). I step outside to snip a couple of inflorescences to bring into the house and breathe in an intoxicating perfume resembling stocks, hence its common name Sweet Rocket. My RHS A-Z Encyclopaedia of Garden Plants reminds me this is a biennial or short-lived perennial and indeed there have been several years where this understated beauty has been absent from the garden when I have omitted to replace it.
Towards the top of one of the supporting posts of the wooden archway which frames the seating area at the rear of the garden, a dozen or so white rose blooms resist the onset of night. I planted the aptly named ‘White Star’ climbing rose two years ago and it is vigorous and healthy. In March I pruned the rose and trained its stems in a spiral, attaching them to strainer wire which I installed on the four faces of the wooden post. I am delighted at the outcome: blooms evenly distributed from base to top, the glossy dark green leaves highlighting the large, waxy and very fragrant flowers.
Rosa ‘White Star’
Half a kilometre away in Kew Gardens I imagine other pockets of white flowers glimmering in the darkness. The collections of Philadelphus and Deutzia no doubt look ghostly at this time of day. As might the starry white bracts of Cornus kousa and the drooping cotton handkerchief bracts of Davidia involucrata. But for sheer scale and profusion of white flowers, a large tree which stands near the entrance to the North Wing of the Temperate House must make an impressive nocturnal spectacle. The branches of the Chinese Fringe Tree, Chionanthus retusus, droop almost to ground level, weighed down with their shredded white flowers, creating a cool cavernous space which invites games of hide and seek.
The Chinese fringe tree framing a view of the Temperate House
Whilst on the subject of Kew Gardens, last Monday, during my weekly three hour stint in the plant shop, a visitor from Seattle showed me an image on her phone of very tall blue spiked plant and asked me to identify it. I recognised the plant as Echium pininana, giant viper’s bugloss, and my colleague confirmed the the shop stocked the seeds in the Thompson & Morgan World Garden range.
Coincidentally I had, like the Seattle visitor, seen a mass planting of these huge biennials in St James’s Park a few days before, creating an almost prehistoric effect. Nearby, in a shadier location, I was very taken with a glorious display of foxgloves, honesty, heuchera and a fern, Cyrtomium falcatum. The only reason I was able to identify the fern, was that I bought one at a plant fair at the Garden Museum in Lambeth at the beginning of the month. It has broader individual leaves than most ferns and is now growing happily in a dimly lit spot beside the back door. Unlike the garden’s white flowered plants, however, it fades into the darkness when night falls.
The common names of plants often reference other plants. For example, the ‘tulip tree’ (Liriodendron tulipifera). Not only do its generous waxy cream goblets resemble tulips, its uniquely shaped leaves with their truncated upper edges remind me of stylised versions of the flower. And this weekend I came across the ‘snowdrop tree’ on Instagram, Halesia Carolina, whose snowy white bells are reminiscent of the blooms of its namesake.
Another tree whose flowers resemble another species, and which is in glorious flower at the moment, is the foxglove tree, Paulownia tomentosa. Four examples of the tree occupy a corner to the right of the Garden House in Mrs Child’s Flower Garden at Osterley, one of which stands slightly apart from the others, behind the wall in the section of the garden where stands the unusual species of strawberry tree, Arbutus madrona, which I featured in my blog dated 17 April 2019.
Like foxgloves, the tree’s petals are a fleshy tubular shape with a flared rim to entice pollinators. Approximately 5cm long, the mauve flowers are topped by exquisite tan calyxes, like suede jackets shrugged over elegant pastel ballgowns.
When after a heavy shower last week I picked up one of the many flowers which the rain had loosened onto the ground beneath the tree, I detected a strong violet scent. The ripened seed cases are almost as attractive as the flowers themselves, being egg-shaped capsules containing numerous winged seeds. When driving along the busy Chertsey Road (A316) the other day I noticed Paulownia trees lining part of the carriageway, presumably indicating a toughness and resistance to pollution belied by their flowers’ delicate appearance.
I read that the tree originates from Eastern Asia, notably China, Japan and Korea. And whilst it is an introduced species in Europe and the USA, it was interesting to note that fossilised Paulownia tomentosa leaves have been found in Washington State. The name Paulownia was given by the German botanist Philipp Franz von Siebold in honour of Anna Pavlovna, 1795-1865, daughter of Tsar Paul I and wife of William II of the Netherlands: hence the tree’s other common name, the Princess tree. The image above demonstrates why the species epithet ‘tomentosa‘ meaning ‘covered in hairs’ is so apt.
Shades of mauve and purple are prevalent in gardens this month as shown in the images which follow. From left to right: Cerinthe major ‘Purpurascens’; Centaurea montana; Lavandula stoechas; Allium ‘Purple Sensation’.
I recently completed the third front garden planting makeover since launching Weeds Roots & Leaves last autumn. The brief was to replace low box hedging and five larger box balls, all of which had been decimated by the lethal combination of box blight and box tree caterpillar, with Ilex crenata, Japanese holly. Whilst the central circular hedge and that beneath the bay window of the house were relatively easy to extract from the sandy soil, the mature box balls were reluctant to relinquish their positions, having developed very tenacious root systems. They eventually yielded in the face of extreme determination on my part, leaving behind soil in the planting holes which was depleted and dusty. I worked in several bags of well rotted farmyard manure and topsoil in order to improve the soil. This week, with the welcome help of a friend, I re-planted the hedged areas with 56 Ilex crenata plants which I sourced from North Hill Nursery in Chobham, using 2 Litre plants for the bay window hedge and 1 Litre plants for the circular hedge.
Because the garden already has a restrained dark green and cream colour scheme, I planted Anemone x hybrida ‘Honorine Jobert’ behind the bay window hedge. The gently curving bed beside the path to the front door already contained two fine Skimmia japonica ‘Kew Green’ and I added a further specimen of this glossy leaved cultivar in the space left by a box shrub as well as two more beside the wall bordering the pavement.
When I visited Prince Charles’s gardens at Highgrove on Thursday for a guided tour, I learnt that even a future monarch’s plants are not immune from box blight. On a couple of occasions during the tour the guide pointed out box substitute hedging. The first of these was Euonymus ‘Green Rocket’, a low hedge of which surrounds a bed in the Sundial Garden, framing the deep red flowers of an Anemone coronaria cultivar and the blue of Camassia leichtlinii. The guide explained that as soon as the box shows signs of infection or infestation it is grubbed out and replaced with alternative evergreen hedging. It was good to see that many box plants are thriving throughout the garden indicating that the strategy appears to be working. The other example of a successful substitution was in the very impressive walled Kitchen Garden where the box hedges had been replaced with Teucrium x lucidrys, commonly known as germander.
The two hour tour took in much of the extensive grounds and, since photography was unsurprisingly not permitted, I jotted down the notes from the guide’s commentary and my impressions of a garden which has been 35 years in the making. A distillation of my notes follows.
A ‘signature plant’ whose bright yellowish green foliage highlights several sections of the garden is Philadelphus coronarius aurea, golden mock orange.
Throughout the garden are examples of what the guide described as ‘Highgrove whimsy’: wooden or stone pavilions and summer houses which I interpreted as the C21 equivalent of William Chambers’ ‘follies’ for George III at Kew.
The organic site is managed on sustainable principles, with all plant waste being recycled for mulch and compost and rainwater collected for irrigation. Biological control methods are implemented rather than pesticides. I was surprised to learn that in two areas of the gardens where azaleas are planted in raised beds, the soil is imported from Bowood House at Calne in Wiltshire approximately 22 miles away.
Camassia leichtlinii interspersed with deep red tulips are currently in bloom in the large wildflower meadow to the south east of the house, where the soil is Gloucestershire clay. An avenue of hornbeams, edged with low willow hoops, leads across the meadow to the Winterbourne Garden where more exotic species such as Chusan Palm and Tree ferns create an exotic display.
From here a long high walled corridor lined with waist height terracotta pots planted with azaleas, runs between the Kitchen Garden and the Arboretum. Halfway along this Azalea Walk a gate decorated with Egyptian hieroglyphs leads through to the Arboretum. The hieroglyphs read ‘The flowers in the garden are a reflection of the stars in the sky’.
In the Arboretum the acidic soil occurs naturally and acers and azaleas abound, the predominant colour being the pinkish red of Acerpalmatum ‘Shindeshojo’. The understorey included Narcissus jonquila ‘Sun Disc’ and wood anemones.
An apple arch leads through the Kitchen Garden to a ring of Malus ‘Golden Hornet’ at the centre of which stands a pool into which a woven willow frog ladder has been lowered to assist exiting amphibia. Several gardeners were planting up the vegetable beds when we toured this part of the garden.
One of my favourite parts of the garden was The Stumpery, with upturned tree trunks accommodating a profusion of Tellima, ferns and species of Epimedium, Dicentra, Trillium and Pulmonaria. The genus which recurs throughout this area is Hosta and the guidebook reveals that Highgrove holds the National Collection of large and broad-leaved hostas.
Topiary features in many areas of the garden such as the yellow yew balls either side of the Thyme Walk which the garden team have fashioned into crowns, helter- kelters and cakes, and the extensive yew hedge which surrounds the most formal parts of the garden and which was designed in 1989 by Sir Roy Strong.
As we drove away from Highgrove a cloudburst descended which accompanied us most of the way home, the only comfort being that hopefully the Ilex I had planted two days before were receiving a similar drenching. Rain, or the lack of it, was a popular topic in the Gardeners’ Bothy at tea and lunchtime at Osterley on Friday, where my gardening week concluded. The previous day’s heavy rain in the West Country had made less of an impression in Middlesex and it remained dry during our garden volunteering duties on Friday save that at 3.15pm as we were preparing to leave the heavens opened and gave the gardens a much needed soak and us a good excuse for a cup of tea.
The Friday team was deployed in the Winter Garden in the morning, cutting back the colourful stems of the willows and Cornus, before they begin to leaf up further and make pruning a heavier job. This will encourage the plants to develop fresh stems this summer in preparation for another display of orange, red and yellow stems next winter. Head Gardener Andy pruned out branches of the large variegated hollies in the Winter Garden which were beginning to revert to a dark green. These prunings were shredded in the afternoon and deposited onto the pile of plant material in the yard which is the first stage of the composting system.
To the accompaniment of the shredder we split into smaller teams in the afternoon to work in and near the Tudor Walled Garden. Two of us weeded the area through and around the bean supports in the bed into which most of the edibles have been planted so far this year. Another three pricked out seedlings which will be hardened off in the cold-frames before being planted out in the next few weeks. The week before we had planted both flat leaved and curly parsley and lettuces in this bed which is divided into four quadrants, the planting lines having been marked out with twine. Slowly but surely the foundations are being laid for the profusion of crops which this bed will be producing by the end of the summer.