Growing in the Middle Atlas mountains of Morocco at subalpine altitude; 2000 – 2500metres, Ranunculus calandrinoides demands a rocky free draining substrate where the roots can grow down deeply into the soil.
Growing on the alpine wall here in Edinburgh, the glaucous foliage remains evergreen. Sprouting from the leafy clump are the flowers. The petals scrolled delicately in bud, opening through pink to white these reach 150mm maximum height. Looking closer the delicate veining through the petals will become evident.
A lesser known member of Hamamelidaceae
The flower parts burst out of their protective bud casings as the weather warms.
Last Thursday, the 10th February, was the first day this winter that the sun shone for a prolonged period, a total of 7.5 hours. The previous time we had a sunnier day was on November 11th. The weather records show what a sun deprived winter we have experienced. This sunny weather released the much appreciated winter scents. The relative warmth drawing the floral perfumes out into the air from the Hamamelis and Sarcococca species now in bloom through the Garden.
White stemmed Rubus
The tough, thorny, arching stems reach 2 metres in a growing season. At the start of March cut these back to ground level. A fresh crop will emerge and as the rootstocks establish they will colonise ground with underground stems.
These plants originated from seed collected in China. Growing in Sichuan Province near the Balang Shan Pass on the edge of a landslip at 2500 metres.
A season to sneeze
Alnus japonica, a deciduous pyramidal tree, this specimen collected in 1987 by Warner and Howick during travels to Hokkaido Province, Japan. The parent plant was found growing at 50 metres near Urahoro. It tolerates wet infertile soils and is a pioneer plant establishing readily gaining a foothold with roots that bear nitrogen fixing nodules promoting soil stabilisation and facilitatating a secondary plant community to develop.
The male flowers are set within pendulous catkins and open, shedding pollen. The female scaly brown cones (correctly; strobiles) are still visible on the tree from last year. By now these have shed their seed and are becoming brittle.
Chemical compounds produced in the bark of Alnus japonica have been isolated and found to have an anti viral effect against sub types of avian flu.
As observed during February 2010
Continual snow cover since 18th December until 15th January; cold desiccating winds and low temperatures. The 100mm soil minimum reached -13.7oc on 24th December. The air temperature recorded below zero from 1st December 2009 until 10th January, with the exception of Tuesday 15th December when we recorded +0.1oc. These factors combined to make life very difficult for evergreens. With frozen soil around the roots these plants could not take up soil moisture to replace that lost through transpiration. The evapotranspiration rate during periods of cold winds is high and the following plants illustrate damage that has occurred at the Garden this winter.
Two plants with thicker leathery leaves that did not appreciate the cold were the Kadsura japonica at the bridge in the rock garden and the well established Gordonia in the M beds. Both have severe discolouration to the leaves.
Nearby are patches of Bergenia which have "gone flat" with the cold. The normally messy clumps of evergreen leaves almost looked tidy as they reduced their surface area and flopped.
The tightly rolled leaf bud spires of Lysichiton americanus show burnt tops; these will rapidly grow out of this damage as only the outer sheath bears the brunt of the cold damage.
Surprisingly the two metre tall woody Phygelius 'African Queen' has remained green to the tip of its fresh soft shoots. Nearby, last seasons growth on Penstemon c.v. is browned.
In the south facing borders at the front range Callistemon citrinus 'Splendens' has desiccated growth, yet still gives off it's citric odour. Erica caffra from the Cape resembles a Christmas tree on twelfth night having dropped 50% of its needles due to the cold. The east facing border with the Crinum collection is a mass of mush, the leaves having turned prematurely to compost.
Plants are resilient, don't be tempted to grub out or prune cold damaged vegetation until rising temperatures and a more benign climate returns as spring arrives. A mention of spring must include the scented pink blooms of Daphne bholua standing sentinel in the corner of the sunken courtyard to the north of the Front Range. Always a positive sign of better things to come.
A cathedral of catkins
Corylus colurna; a forest tree of grand proportions. With a trunk of deeply fissured bark reaching up to a magnificent cathedral of branches this tree is now laden with catkins. Stand beneath and appreciate the structure of the tree as you gaze up through the deciduous canopy set against a blue sky.
Initially the catkins are a mute yellow tinted red. As they mature, shedding copious amounts of pollen, the colour fades to brown. Held in groups and reaching 70mm in length these bear the male flowers.
The attached magnified light microscope images taken by Frieda Christie show the detail of the shield protecting the pollen holding anthers. These change colour once the pollen has been shed. Spherical grains of pollen shed from the ripening anthers can also be seen, dry and light, these grains are wind distributed.
Not a thing of beauty
The leaf is composed of usually five leaflets, thick and leathery in texture. Held to the branch by a distinctly shaped sheath. The branches have a flexible almost pliable feel to them and consequently the framework becomes wide spreading.
The inflorescence is a compound umbel. Each individual umbel rounded with flower buds held on short sturdy stalks. All stalks composing the umbel are a purple shade, setting off the inflorescence against the foliage.
They must breed hungry sheep in New Zealand; the ability to graze over the hard spears of Aciphylla subflabellata requires determination. The plant was observed growing in grazed fields on South Island at 516m by father and son team; Barry and Robert Unwin during a plant collecting trip in 2005.
The plant has an open growth habit composed of multitudes of spine ended leaves. Set almost spiral fashion. This winter they have developed a definite brown hue. Benefitting from a free draining root zone these are fast establishing members of the Umbelliferae family.
As observed during February 2009
Braw; a late 16th century Scottish word, a variant of brave. Nowadays meaning fine, excellent, attractive. Words that describe the developing flower buds of Rhododendron lanigerum. At this stage these terminal buds populate the plants near Inverleith House. The scales are a soft felty brown colour. As they expand nearer flowering time they open out and shed to reveal the petals.
Observe the leaves in their drop down state, a physiological adaptation to conserve moisture loss through transpiration, by presenting a reduced leaf surface to the air during cold spells in the winter. It does however give them a bat like appearance. The light brown indumentum covering the reverse of the leaf can be seen in the attached images.
Native to the Eastern Himalayas and China. These plants were collected in Tibet by Frank Kingdon Ward during 1924. Growing to 7 metres as a small tree or large shrub where it forms dense thickets. The bark becomes craggy on young growth and fissures, cracking and breaking off.
As blizzards of snow envelope Britain the "Winter Aconites", Eranthis hyemalis, show through the white blanket that carpets the land. With a wide geographical spread from Europe to the Himalayas this rhizome sends up a stalk of light bronze with immature leaves a similar colour. The underground part of the plant is a rhizome, long, thin and mis-shapen with straggly roots coming off.
The deeply divided leaf is crowned by the bright yellow flower. As temperatures increase the cupped petals open to reveal the flower parts. Left to their own devices the clump soon bulks up, seed is freely produced and in undisturbed soil seedlings are visible around the mother plant. These take three seasons to reach flowering size.
Look at the companion planting in the image, slowly establishing is a seedling of "Annual Meadow Grass", Poa annua. A timely reminder to all that the soil is warming up and the next generation of weeds are developing. Spring is arriving and with lengthening days the opportunity to spend an hour in the garden as the soil dries out and becomes workable must be taken. Get on top of the weeds now and a relaxed summer is guaranteed.
Celebrating the snowman as art
After days of watching news bulletins showing snow covering many areas of Britain; finally last night the flakes started to fall. Silently 50mm of snow layered itself gently over the Botanic Garden. With the grass minimum thermometer reading -9.1oC the snow cover was guaranteed to last.
These images show the diversity of the snowmen as interpreted on lawns and bridge parapets. They range from those with doleful eyes to a giant, the guardian of the rock garden. Many use plant material to illustrate features and one successfully advertises our Terrace café where cold hands tingle as the feeling returns and parents are revived in a warm comfortable environment.
Be quick if you want to see these or add to the collection. The Garden is open from 10.00am - 4.00pm daily.
Store cupboard staples
Viburnum betulifolium is a strong growing deciduous shrub. It is laden with bright red berries, ideal bird food. The shiny surface must act as a visual deterrent as most are uneaten. These remain on the plant late into the winter; only rarely do I see birds pecking away at the berries. It could be that they are waiting for the conversion of the starch content to sugar to make them more palatable.
A vigorous plant sending out from its base sturdy shoots. These easily reach 2.5m in length forming thickets in secondary forest where they are found in Yunnan Province, China.
Gathering of Galanthophiles
The end of the week sees the first Scottish Snowdrop Conference. Held on Friday 20 February at the Garden it is part of the Scottish Snowdrop Festival. In the library foyer is a display of historic photographs and botanical illustrations from the library and archives on the Genus Galanthus. Included is a snowdrop model used by John Hutton Balfour, Regius Keeper 1845 - 1879. Also represented are very early woodcuts of Snowdrops and Snowflakes from 1576 and one of the earliest British representations of Snowdrops and Snowflakes from J.Parkinsons' Paradisi in Sole, 1629. These compliment the species and cultivars growing throughout the Garden.
What better way to highlight one family's passion for plants than to mention two cultivars we grow at RBGE? Galanthus 'Mrs. Backhouse's Spectacles' and G. 'Backhouse No.12', raised by one Robert Ormston Backhouse 1854 - 1940. He and his wife raised these Galanthus cultivars at Sutton St Nicholas in Herefordshire. Robert came from a County Durham Quaker family, previous generations of whom were bankers, horticulturalists, nurserymen, (founding a 100 acre nursery on the outskirts of York), foresters and missionaries amongst many other professions. Earlier generations of the family grew a collection of Narcissus which formed the basis for a classification system of the genus.
The images show a slight difference in the darkness and size of the green splash on the inner tepals. Larger and darker in G. 'Mrs. Backhouse's Spectacles'. This cultivar also appears more bulbous in bud. I guarantee a lot of people will pore over these minute differences on Friday!
Sticks in the snow
The recent snow has given the edge to plants grown for their winter stem colour. The light green stems of Cornus stolonifera ‘Flaviramea' show up as the sun, low on the winter horizon, sends a shaft of light through the border. The species, C. stolonifera, having red bark, is native to North America where it is widespread.
The best way to manage these deciduous shrubs is by stooling annually. In late March, just prior to bud burst, ruthlessly cut to ground level all the previous years' growth. As the plant ages it becomes a mass of twigs from which fresh growth appears. If left to its own devices it reaches 3 metres with intertwined growth. The vigour and glabrous stem colour is lost with ageing.
For previous years' highlights during this month, see the February Garden Highlights Archive page.
As observed during February 2008
A Himalayan treasure
Various forms of Daphne bholua are planted throughout the Garden. The earliest to flower is towering up 5 metres from the sheltered courtyard to the north of the Glasshouses Front Range. Carefully lean over the railings and breathe in the heavy scent exuding from this plant. The flower clusters terminate last year's growth, a light violet in bud, opening white.
This plant is native to the Eastern Himalayan mountain range and is found as an understory plant beneath Tsuga dumosa forest, with evergreen Magnolia and Quercus sp. The image shows a plant with white flowers in November on the road from Dochula, Bhutan at c.2900m where views to the snow capped summits of the Himalayan peaks border Tibet. As with cultivated specimens, the evergreen leaves have a chlorotic appearance to the edges which are prone to curl in on themselves.
The flower colour within the species is variable and the plant growing to the west of the Orchids & Cycads glasshouse is very lightly shaded pink in bud. From a distance, the overall appearance is of a mass of white bloom. This plant is one of the seedlings collected at an altitude of c.3000m by Peter Smithers on the Daman Ridge, Nepal.
Another collection from Eastern Nepal, growing at a slightly higher elevation c.3200m, was made by Spring-Smyth, who was an officer in the Gurkha regiment. His find was given the cultivar name 'Gurkha'. Differing from the evergreen type species this cultivar flowers on deciduous wood. 'Gurkha' has fusty purple pointed buds. These elongate and emerge from a sheath of sepals as terminal clusters on the previous year's growth. This growth is highly polished wood pitted by leaf scars. A good specimen grows in the south-facing border adjacent to the Alpine House. Again, as if to prove the variation within the species, this has an overall deep pink appearance and an upright form of growth.
Avoid standing or walking on cultivated soil when appreciating these plants. Constant foot traffic over cultivated areas will result in compaction and loss of pore space in the root zone resulting in a reduction in vigour of the plants.
An alpine odyssey
This week has brought lengthening days, warmth from the sun and bud burst from many of the dormant clumps of herbaceous plants throughout the Garden - all signs that spring will soon be with us. It may take longer for the soil to warm up this year on account of the increased rainfall we in Edinburgh have experienced this January, a total of 167.1mm. This compares with the past 19 years' average of 72.8mm. Sunshine levels have also been low which may be due in part to rain having fallen on 26 of the 31 days of January 2008.
This week the Alpine House is worth a visit. Of special mention is Helleborus thibetanus, a native to China originally discovered by Pere Armand David in 1869 in Sichuan Province but not introduced to cultivation until the 1980s.
A choice plant rarely seen in cultivation, it bears light pink petals in globose hung form on a stalk of 150mm. Within the head are a ring of fresh green nectaries. The leaves have red thread veins running from the leaf stalk into the divided leaflets. The watercolour-washed green surface of the leaf is imprinted with a textbook true network of veins. A saw tooth edge from the leaf tip running two thirds of the length completes the picture of a choice member of the family Ranunculaceae.
Also providing colour on the south side of the alpine house are representatives of the spring flowering bulbs and corms; Narcissus, Crocus, Cyclamen; Gymnospermum, Ranunculus, Corydalis and a promise of a good show from Primula allionii are also present, all pot grown and sunk into the raised benches of sand to maintain a cool root zone.
Rose - a thorny issue
Rosa sericea ssp. omeiensis forma pteracantha - the longest sequence of names and the most decorative of thorns are this plant's claim to fame. As there was no possibility of finding a bunch of twelve red roses in bud in the Garden, this species will have to suffice representing St Valentine's Day.
As can be seen from the two images, the broad, flattened spines are variable in colour, shape and size. In colour they vary from near translucent to a dull brown through many attractive shades of red. The stems are often populated with a multitude of small spines.
This strong-growing rose is best pruned to allow young shoots to regenerate from the base of the plant - the young wood produces the best stem and spine colour. As the wood ages, the colours depreciate in their intensity.
An early currant
An evergreen shrub with leathery leaves, Ribes laurifolium is a native of west China, introduced to Britain in 1908 by Ernest Wilson. The flowers are produced in racemes that elongate pendulously over a week of warm weather to 75-80mm in length. When in tight bud, these are more attractive than the extended inflorescence at maturity.
The flowers take on a white appearance en mass, however each of the five petals and central boss has a distinct lime-green shade. These are fused at the base from where the single sepal arises, acting as a shield to the individual flower.
Planted opposite the Arid Land House, tucked away on a south-facing wall beneath a canopy of vegetation, this evergreen is thriving on dappled sunshine. The nectaries at the base of the individual flowers are glistening with liquid, sweet to the taste. In the nectar pool are splashes of orange colour, invisible to the naked eye, resembling vestigial anther heads. Most descriptions of this plant describe it as dioecious, that is male and female flowers produced on separate plants. In these images, taken through a light microscope in the Garden's SEM Suite (6.5 x magnification) by Frieda Christie, distinctive anthers can be seen, held free from the petals with a short filament strand.
The plant is slow to establish but will grow to about 1.8 metres with weak woody shoots when cultivated successfully. It is best grown through or up a support, allowing the pendulous flowers to be seen to full advantage.
A choice plant from the coastal mountains of Chile
Latua pubiflora is not to be missed. Possibly one of the choicest plants to come out of recent plant collecting expeditions to Chile. This introduction is from the joint University of Chile, RBGE expedition during 1998.
It was noted as an unprepossessing plant with yellow fruit found growing as a spiny shrub to 2.5m in alluvial gravel deposits on the eastern bank of the Rio Quihuis in the Los Lagos region of coastal mountains within Southern Chile. Growing at an altitude of 140 metres on a sparsely vegetated river bank.
Called "El Loco" as it is highly toxic when ingested, as is typical of many Solanaceae family members.
Staged opening of the flower buds occurs. These appear from the dormant growth buds and expand to 40mm into tubular corollas with a 5 pointed splayed end beyond which the extended stigma protrudes. The buds are encased by dark purple sepals which are forced open by the extending bright purple corolla tube. Hidden within are the 5 anthers held on filaments, the base of which are covered in fine white hairs.
Here in the nursery it reaches 4 metres as a very healthy strong growing deciduous shrub. As the girth of the main stem increases the bark splits revealing fissures, dark green and brown in colour. As previously mentioned it is spiny, these are prominent and extremely vicious spines. The growth can be managed by cutting back to ground level after flowering in April. This will give rise to the prolific production of watershoots from the pruning cuts. If this is done every six years the plant will remain manageable. Our plant, now ten years old has great vigour and a wide spreading head.
Young plants growing in a nursery bed can languish for several seasons then vigorous shoots will sprout from the base of the plant and reach 1.3 metres during the course of a single growing season. Could this be the hedging plant of the 21st century; reliably floriferous, barbed to repel, and responding positively to pruning cuts?
For a detailed description of Latua pubiflora read the article by Martin Gardner and Sabina Knees in The New Plantsman September 2000; Vol 7 Part three, pp.184 - 190.
Spring bulbs and leaf mould
Spring bulbs are making their presence known; the Crocus cultivars are in flower on the west slope from Inverleith House and at the east gate. Groups of Narcissus bugei from Spain and Scilla mischtschenkoana from Turkey, Iran and the Caucasus in the demonstration garden and alpine area. Miniature Narcissus cyclamineus, Leucojum and Iris in the Rock garden.
The arrival of warmer weather also heralds the appearance of the green cotyledons of germinating weed seeds. Now is the time to spread material from the compost heap as mulch over cultivated soil to smother these before flowering stage is reached and a potential further generation of seed is produced.
The diamond geezer of organic matter is leaf mould. In the Garden we collect the leaf fall from the previous autumn; store and by turning regularly produce crumbly, friable leaf mould. This is returned to cultivated areas of the Garden as mulch increasing the humus content of the soil.
The image illustrates the different rate of breakdown of the softer cellulose tissue compared to the lignin within the leaf. Deciduous leaves decompose faster than the more leathery resilience of the evergreen species. All will make ideal feedstock for the leaf heap. Check around border edges where leaves congregate over winter and rake out to allow grass to recover.