Plants of the week- August
Our team are always on the look out for new developments in the gardens. Each week, our Living Collections Manager, Graham, will be sharing some points of interest with us.
Our plant this week is Reevesia pubescens, a rare Himalayan semi-evergreen shrub planted at the rear of the Rock Garden in April 1989.
First scientifically recorded in 1874 in Sikkim, a state in north eastern India bordering on Bhutan, Tibet and Nepal, the plant wasn’t introduced to the west until Ernest Wilson, the renowned and prolific plant explorer, sent seeds collected in 1920 from the Szechwan province, at the northern extremity of the species’ range, for distribution by the Arnold Arboretum.
From the family Malvaceae, formally in Sterculiaceae, Reevesia pubescens’ stems and leaves are densely coated when young with a bronzy pink indumentum turning dark green and leathery with age. Leaves vary in both size and shape. Creamy white flowers are produced throughout July and August and its sweet fragrance hints of jasmine and honeysuckle. Mount Stuart’s specimen is 4 metres in height; possibly the only specimen growing outdoors in Scotland. Other UK sites to find this rarity are Tregothnan and Caerhays, both in Cornwall, enjoying a similar mild maritime microclimate to Bute’s.
Our plant this week is Eucryphia glutinosa, a native of woodland Chile from the family Cunoniaceae, known commonly as the brush bush. This large deciduous shrub has glossy dark green leaves which in autumn turn red and orange and in the summer produces sweetly fragrant pretty four-petalled white flowers which as you can see are highly attractive to bees, butterflies and other insects.
Eucryphia glutinosa favours a moist but well drained soil in a sheltered sunny location, and this example has grown to 10m tall since being planted in the Wee Garden in the 1930s. Its name “glutinosa” refers to the stickiness of the flower buds before opening.
From the Pinaceae family our chosen plant this week is the evergreen conifer Abies koreana, the Korean fir which is listed as endangered in its natural environment. It’s a popular ornamental plant, grown in parks and gardens in temperate climates for not only its foliage but also its abundant cone production which is seen even on young trees.
Relatively slow growing, Abies koreana is a compact tree of conical outline, with needle-like leaves dark green on top and silver underneath and handsome blue or purple cones. It prefers a sunny but sheltered location with well drained neutral to acidic soil and this specimen is ideally situated in the Rock Garden.
Planted 40 years ago, our specimen has a flat top as it lost its leader and so doesn’t display the usual pyramidal shape but stands at 5m high and is currently heavy with cones. It’s much smaller than the 15m specimen planted 50 years ago in the Wee Garden which is a noted Scottish champion tree.
If we were ever to need to replace the Rock Garden tree an established tree of the same height would cost £4,000!
Whilst the Campanulaceae family’s more familiar Lobelia members include both traditional ground covering blue bedding plants and the popular trailing plants of many hanging baskets which originated in South Africa, their more dramatic and eye-catching South American cousin is Lobelia tupa. Although a woody based perennial it’s treated at this latitude more as a herbaceous perennial and hails from Chile where the Mapuche Indians consider it a sacred plant, perhaps due to its hallucinogenic properties, though toxic.
Its common name is Tabaco del Diablo – Devil’s Tobacco – reflecting its stunning downy foliage similar that of tobacco, held on dark red-purple stems which produce blood red, tubular flowers in late summer and autumn as can be seen now on our specimen in the Wee Garden.
Poisonous to humans, horses, cats and dogs but curiously not to livestock or birds Lobelia tupa grows to 2m in height with upright stems making it a great addition to sunny flower borders and beds.
Eucryphia × nymansensis
Our final plant of the week in August is Eucryphia × nymansensis, a hybrid of the two Chilean genus of Eucryphia – glutinosa and cordifolia – named after the National Trust’s Nymans Gardens in West Sussex where it was first raised during the First World War. In 1924 the RHS awarded Eucryphia × nymansensis an Award of Garden Merit, the Oscar of the horticultural world. From the Cunoniaceae family, and more commonly known as Nymans eucryphia, it’s a dense evergreen tree with glossy dark green leaves and rose-like pure white flowers in late summer and autumn.
Like many of the temperate loving South American plants at Mount Stuart Eucryphia x nymansensis thrives in an environment of moist but well drained soil with sheltered sunshine and are noted for their suitability for the Gulf Stream influenced warm and wet conditions of Bute, companions for rhododendrons and magnolias, all good woodland garden plants who like acidic soil.
We have three specimens of Nymans euryphia, two in the South shrubbery and one in the Wee Garden, planted in the late 1960’s, the tallest of which is over 16m in height. Low maintenance, they need little pruning or trimming and are resistant to pests and diseases due to their glossy leaves.