As observed during January 2008
4/1/2008
Jasminum nudiflorum is the ideal plant to appreciate from the warmth of your home and a pleasure to encounter when garden visiting at this dreich time of year.
The winter jasmine is hardy, adaptable to all soils and aspects, reliable to flower, easily propagated, living well with neglect or reacting vigorously to seasonal pruning. This is one plant that deserves a place in every garden. Native to Northern China, it has been cultivated in Britain since 1844.
The stem is square in cross section with a pithy centre. It remains green for two years and then turns light brown with age. The scandent growth is barely self supporting, appreciating a wall where young shoots can be tied in. If grown in the open, try it over an arch of chicken wire. This simple frame will support the early years' growth and soon become hidden by the arching stems.
Deciduous in winter, the fresh yellow flowers are produced from well spaced opposite buds. The corolla is tubular at the base, dividing into six flattened petals giving a good spread of colour. The stigma is prominent to the anthers.
When frosted, the colour drains to leave the petals translucent. Unfurled buds are not affected. Specimens can be seen tucked away in the west border and behind the scenes in the alpine yard.
7/1/2008
Pete Brownless, nursery supervisor for almost two decades, is also the author of the Greenfingers column in our quarterly magazine The Botanics. Pete has been writing this column focusing on plants he grows and knows from personal experience. He's a plantsman who crams his own garden at home with plants from all climatic and altitudinal zones of the world, many of which he has collected personally on expeditions to South America, Japan, China and mainland Europe right to the land bridge with Asia.
By this you will understand how his north facing windowsill in the office (which we have shared for too many years), is populated with an eclectic range of potted plants. Even the pots themselves have style.
In the attached image from left to right can be seen:
- Bowiea volubillis, a member of the Hyacinthaceae family. The succulent, scaly, green bulb sits on the soil surface supporting stems that feel distinctly cool to the touch. All green parts of the plant photosynthesise.
- Gymnocalycium mihanovichii c.v. with no chlorophyll grafted onto Hylocereus sp. rootstock where it resembles a designer styled hat. These appear in a selection of chlorophyll reduced or missing colours; yellow, red, burgundy, white, black, often seen in garden centres as a novelty plant.
- Lophopora williamsii. Of mid-green insignificant appearance, but what a background. Known as Peyote, the Mexican and Arizonian Indians used to chew the plant to induce visions for medicinal and ceremonial occasions.
- Ceropegia linearis. A second plant in the collection with thin trailing stems needing a form of support. If left to grow along the ground, miniature tubers will form at the nodes. These can be grown on as propagules. The distinctive triangular shaped leaves have white marbled veining, waxy to the feel.
- Rechsteineria leucotricha (syn Sinningia canescens). A Brazilian Gesneriad with a semi-buried tuber. The shoots and leaves are covered in minute white hairs giving a soft downy look to the plant. Flowers are orange and loaded with nectar, which has a habit of dripping out of the tubular calyx.
- Aporocactus flagelliformis, the 'rat tail cacti', with shoots that can reach 1.2metres in length. Ephipytic in the high plateaus of Mexico where the red flowers are pollinated by hummingbirds.
- Clivia miniata, which has long been subjected to an irregular drought experiment; we all forget to water it when Pete is away. Despite this it flowers annually in April. Members of the genera detest root disturbance and will accept dust dry conditions and shade. Clivia species, hybrids and cultivars can be seen in the north side of the Temperate Lands house growing beneath the raised walkway. C. gardenii is in bloom now.
11/1/2008
Tree ferns lend a touch of the exotic and provide key architectural elements in the Queen Mothers Memorial Garden and alongside the Glasshouse ramp. Hailing from such diverse places as Australia and South Africa, these predominantly tender species may not survive our Scottish winters without protection and therefore, as a precaution, individual plants are wrapped in November before the onslaught of the winter chill.
The shortest day may have passed, but the middle of January is the coldest time of year for us. Our temperate maritime climate is moderated by the sea around the British Isles. The latent heat absorbed in the seas during the summer past has now lapsed and we are at the mercy of an icy chill approaching from the east.
It is a prolonged freezing spell that does the damage to tree ferns from the Southern Hemisphere, the odd night of frost will cause little if no damage.
To protect many of our tree ferns, straw is wrapped around the trunks, wired in place with netting. The crowns are especially vulnerable containing the growing point. These are protected with a handful of straw, topped with slates of polystyrene, in turn covered with a second layer of straw. The broken slates of polystyrene as well as insulating also deflect rain water from the crown.
Cyathea dregii, C. dealbata and C. smithii have been given this treatment. A fuller description may be found in the article 'Winter Protection of Tree Ferns at the Royal Botanic Garden Edinburgh' by Andrew Ensoll, L.Galloway and A.Wardlaw in Sibbaldia No 5, 2007.
You will note that the Dicksonia antarctica in the QMM Garden have protection in the crown only. The trunk of many Dicksonia species are composed of a mass of intertwined roots increasing in girth annually. As the stem thickens with age, the central core receives more protection naturally. Young plants are the most vulnerable from prolonged freezing temperatures. The difference between the air temperature and the ground temperature is influential in their survival as the crown in a young plant is closer to the ground and will therefore experience lower temperatures.
This difference in temperature can be observed from the weather readings taken at the Garden. The grass minimum or ground temperature was recorded as low as -12.5ºC on a succession of days during December 2007 when the minimum air temperature was recorded as -6ºC. That is 6ºC lower at ground level on a succession of days.
Fronds are blackened and damaged when the air temperature falls below -4.7ºC. This is evident in the image of the blackened fronds in the QMM Garden.
A group of ferns are established in a sheltered quadrangle within the Balfour building complex at the Garden. Within this area these freezing temperatures were not recorded. The difference in appearance of the fronds can be seen in the attached images, both taken on 28 December 2007 following five days with freezing temperature of -4º c or less recorded.
14/1/2008
Galanthus 'Lady Beatrix Stanley' is the first snowdrop of the season, the promise of spring. After the week of storms and heavy rain, the snowdrops are opening to remind us that days are lengthening and the sun will warm the air and dry out the soil.
This cultivar has G. caucasicus parentage, double flowers, the outer petals white with the inner spotted green at the tips. The leaves have a glaucous bloom.
This is the time to remind you of the Scottish Snowdrop Festival, Friday 1 February - Sunday 16 March. A visit to Edinburgh, Dawyck, Logan or any of the other participating gardens is highly recommended.
At this time of year, be aware of spring bulbs growing through lawns and grassland when visiting our Gardens and working in your own garden. Established clumps of daffodils will have started to put out fresh roots from the dormant bulb in August of the previous year. The foliage is now well developed and showing amongst the grass. This is vulnerable to foot traffic damage. Similar advice applies when the lawns are frosted - if possible, stay off them as once the frost lifts your tracks remain as blackened footprints; the defining line of the wheelbarrow is worse still!
21/1/2008
A trio of hellebores
Helleborus orientalis, collected in Turkey by E.K. Balls, is now to be found growing in the upper Woodland Garden. This is a showy clump with fresh, white flowers and as with most hellebores, the sepals fade a shade of green once all the flower parts drop, leaving the prominent stigmas pointing outwards. In hellebores, the petals have become modified to act as nectaries. These appear as the inner ring within the sepals, looking like a multitude of green shovel heads. Also see the variable strain 'Winter Queen' in the Copse.
Growing in the same bed is H. x ericsmithii, a sterile hybrid, the result of crossing H.niger x H.sternii (itself a cross between: argutifolius x lividus) The leaves are etched wine red as is the reverse mid rib. White sepals and fresh yellow flower parts clustered are within. The outer of the sepal is mottled, replicating the colour of the leaves. Again, the colours fade as the sepal shape changes to resemble a green shield. Many forms of this cross are in cultivation some with superior leaf marbling and flower colour shades.
It is named after Eric Smith, a plant breeder and selector who in the 1950s worked at Hilliers nursery, Winchester and later in partnership during the 1970s at the now closed Plantsman Nursery in Dorset. Now there is a term to conjure with - plant selector: someone with an eye for detail able to appreciate diversity. The ability to spot the potential in a variation of leaf shape, intensity of colour or muted shade, the form or appearance that appeals and appears different to the usual batch. The term plant selector underestimates the eye this man had for spotting and then the skill to nurture and grow on for distribution the many selected forms of plants during his lifetime.
Botanic gardens throughout the world are the custodians for much of the biodiversity within the plant kingdom. They are now bound by the terms of the Convention on Biological Diversity (CBD), which came into force on 29 December 1993, following the UN Rio Conference of 1992. Its principle objective is the conservation and sustainable use of biological diversity. Each of the 188 signatories is to develop national strategies based on this objective. It provides for the fair and equitable sharing of benefits arising from its implementation and should allow a country to retain the "intellectual rights" of plants collected within its political boundaries.
The raw material for this is held within the seed capsule. Plant collectors should not make commercial use of wild collected material without those countries government's knowledge and approval.
H. argutifolius, a native to Corsica and Sardinia, is a tall bruiser of a plant growing in the quadrangle and also in the Rhododendron Walk. The glossy green leaves are edged with an intricate pattern of spines, facing forward, not dangerous in the least. The flowers are borne in a terminal clump of a very light green. The anthers and filaments almost spiral back into the sepals as the bud opens. After flowering has finished, these shoots can be cut out, giving space for new growth to break out from the perennial rootstock.
25/1/2008
The thin, ribbon-like petrals and delicate scent of the Chinese witch hazel, Hamamelis mollis, welcomes you on entry to the Garden via the East Gate.
This deciduous shrub readily scents the area around it - it is best appreciated in the early morning when the air is still and other competing smells are reduced. The Phenology team recorded this plant's first flowering of the season on 5 December 2007 but not until 11 December in 2006. From these dates it then takes until early January to be appreciated in full bloom.
Flowering magnificently this month, the paper-thin petals, being almost devoid of moisture, are rarely damaged during frost unlike Viburnum x bodnantense, of which a combination of frost and early sun will cause mass discolouration.
The flower clusters are produced on the previous season's growth. Encased in brown felted sepals the hardly discernable flower parts are held deep within these. Individual flowers are grouped in clusters of three or four, accentuating the mass colour and the contrast of the recurved ruby red sepals and yellow ribbon petals.
The growth buds are covered in minute hairs and resemble the hoof of a deer. Deciduous, the plants also come into their own during autumn with yellow and red pigments through the leaves. This is a strong growing plant that appreciates full sun and a well-drained root run. It dislikes root disturbance and pruning but appreciates a top dressing of well rotted organic matter after flowering.
The cultivar H. mollis 'Pallida' also flowers reliably each year and boasts sulphur yellow petals. It tends to initiate bloom slightly later than the species. Both are in full colour west of the Alpine House, where the contrast in flower colour can be appreciated.
Kalmthout Arboretum in Belgium is holding a Hamamelis festival, from 14 January to 17 February 2008. Here the collection of Hamamelis species, hybrids and cultivars can be appreciated. Also, from 7 to 10 February, Kalmthout is staging an International Helleborus show.
29/1/08
Freezing needles
Prominent to the south of the Rock Garden is Pinus sylvestris 'Aurea', the golden Scots pine, described by Rock Garden Supervisor John Mitchell as a classic addition to the winter landscape.
Not that 'winter' is the most appropriate title this week - yesterday, the 28th, we made the first cut of the lawns this season, and as if to confirm temperatures are rising and spring is on the way, the brown scales on the rhubarb buds have burst revealing the promise of growth, not to mention the makings of a good pudding.
A grafted scion onto P. sylvestris, the cultivar 'Aurea' relies on a prolonged freezing spell to bring out the intense yellow pigments during winter. Close inspection of the needles reveals the deepest yellow at the needle tips shading to light green at their base. From early April, depending on air temperature, the yellow colour reverts to a shade of green until the following winter.
Obtained from Dicksons nurseries of Chester in 1907, this initially slow-to-establish cultivar of our only native pine is now 7 metres in height with a proportionate good spread. The image shows a cross section of stem with the closely spaced annual rings, denoting the slowness of growth each year. The resinous sap is visible spreading over the cut surface. With age, the trunk develops deeply fissured bark and takes on the orange glow of the mature Scots pine. 
In the 19th century, Chester became famous for horticulture. The development of the railways contributed to this growth. The ability to supply industrial Liverpool and Manchester resulted in the amalgamation in the 1880s of two family firms, F&A Dickson and James Dickson and Sons, resulting in 400 acres of land in production. At this time they were possibly the largest plant growers and producers in Britain.
Information gleaned from the accession cards in the plant records office records this specimen as having been planted in February 1939 in the Rock Garden - presumably it had been grown on in the nursery since its accession in 1907.
A younger specimen is established in the east valley of the Rock Garden. Planted in 1963, it is now in its 45th year of growth and has a misleading stature as it cascades down from the rock above which it is planted.
As can be seen from the image, a selection of young grafts are growing in the nursery. These were grafted in 2007 by students from the School of Horticulture. As with all plants it is important to have a diverse age range of material where planting and growing space permits. This also allows the students to select good scion material from the growing plant - an important means of determining future plant selection.