Plants of the week - January 2020
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.
Rhododendron arboreum ssp albotomentosum
Providing some very welcome early colour in January is Rhododendron arboreum ssp albotomentosum whose beautiful scarlet flowers appear on our specimen well ahead of early to mid spring when the species typically flowers. This perennial evergreen shrub likes to be sheltered from wind, in dappled sunlight in acidic soils and was first brought to the UK in 1956 by Frank Kingdon-Ward from Mount Victoria in west central Burma, now the Republic of the Union of Myanmar.
A subspecies of the tree rhododendron it has broad, dark green leaves, with a silvery-white hairy coating beneath which gives rise to its name, albotomentosum, which means white and hairy. Its growth is expected to be around 1.25 – 1.5m in ten years, ours is 5.8m high and was planted around 50 years ago.
As we approach the first full moon of 2020 on January 10 and then the Old Scots New Year on January 12 the days slowly begin to lengthen, what could be a more welcome sight in our gardens and woodlands than a clump of Galanthus, snowdrops? The Latin name is derived from the Greek for milk and flower – gala anthos – for the purest of dainty white pendulous bell flowers produced in very early spring, and true to its common name often despite snowfall.
Numbering around 20 species of perennials grown from bulbs, the most widespread variety is Galanthus nivalis which is widely naturalised across a large area of Europe stretching from the Pyrenees through Poland in the north, south and east to the caucuses as far as Turkey. Not being a native British wildflower the snowdrop isn’t a protected species in the UK - it was most likely introduced around the early sixteenth century - but has become an anticipated signal of the turning of the year.
This year Mount Stuart’s gardens will be open to the public between January 25 and March 11 as part of Visit Scotland’s Snowdrop Festival.
In the Wee Garden is an interesting plant from the southern hemisphere, the second generation of a specimen collected in 1995 by a visit to New Zealand and Tasmania by the International Dendrology Society, Banksia marginata. Commonly known as the silver banksia or Tasmanian honeysuckle, the genus Banksia was named to honour Sir Joseph Banks, a botanist who sailed with Captain Cook during his first world voyage in 1768-1771.
This woody evergreen shrub has narrow leathery leaves with silver undersides and produces upright, cylindrical, pale yellow flower spikes – inflorescences – which flower from August all through our winter to April, and feature up to 1,000 individual flowers on each spike. Old flowers remain in situ for several years giving the plant an architectural appearance and our plant is 3m in height and 2m in width.
Indigenous Aboriginals historically used Banksia marginata’s flowers to strain water for drinking and made needles from its red coloured wood. The plants’ sweet nectar was drained by soaking in water. Banksia marginata is generally easy to grow in a well-drained, sunny or partly-shaded position and established plants can withstand drought, coastal exposure and temperatures as low as −10 °C.
Our tie-in to this weekend’s Chinese New Year is from the family Berberidaceae, the large-growing and fragrant shrub Mahonia acanthifolia, native to a large area of Asia including south west China.
It’s an open, upright shrub with pinnate, glossy dark green leaves which can be up to a half metre in length with lance-shaped leaflets. In late autumn and early winter 30cm long racemes with dense, yellow flowers are produced in clusters of three or four, followed by bluish-purple berries. Mahonia acanthifolia is considered the finest Mahonia to be cultivated openly in the UK due to its foliage but it needs a sheltered spot and is ideal for banks and hedging, specifically giving early spring colour.
The fruit is edible, the root produces a yellow dye, and the alkaloid-bearing roots, stem, bark and wood are used medicinally.
Our specimen was planted in the 1970’s and is currently 5m in height.
From the family Betulaeae which includes alders and hazels comes Betula costata, the Korean birch, a deciduous hardwood tree. As we approach the two thirds waypoint of meteorological winter this tree gives all year interest with its stunning and complex bark.
In its native Oriental habitat this large attractive birch can reach 30m in height but is more compact in our park style environment with gently drooping branches which in spring produce long slender leaves. The bark varies from cream to silver, peeling showily from the trunk and large branches in broad papery plates to reveal colour subtleties.
Korean birch wood is close-grained with a satin texture, capable of taking a fine polish and is used both as plywood and for furniture. In 1842 J.C. Loudon noted in his Encyclopaedia of Trees and Shrubs that in the Highlands of Scotland birch branches were used for fuel in whisky distillation, the leaves for smoking hams and herring and its bark for tanning leather. Birch sap can be tapped in spring and fermented to make birch wine which in addition to its many medicinal uses in folklore and herbalism make this tree an all rounder!
This tree was planted towards the back of the Rock Garden around 1987 when it was only 70cm tall, it’s now 12m.