Seasonal Plants of Interest, January 2013
The sun’s excrement
Take a look around when the sun is low in the sky and lighting up the lichens on deciduous tree bark. Xanthoria parietina can be found on the bark of Tapiscia sinensis it also grows throughout the arctic, adding a much needed splash of colour to the white surroundings. The Polar Inuit of Northern Greenland call it “sunain anak”, meaning the sun's excrement.
Currently, X. parietina, is one of the commonest lichens in the UK as it loves nitrogen pollution. It especially likes to live near roads and in cities and is used as an indicator of (poor) air quality.
The good news though, is that we also have clean air/nitrogen sensitive lichens growing in the Garden such as Evernia prunastri . Evernia is also used as an indicator of air quality Xanthoria has been used as a dye to colour many things from fabric to Easter eggs.
Strange we have both but I think that it is the range of tree species growing in the Garden that can explain it - the pH of tree bark has a massive impact on lichen distribution with some lichens liking high pH e.g. Xanthoria and others loving low pH. Trees with naturally high pH (like the Tapiscia sinensis) are more likely to support Xanthoria than those with a low pH (such as pines). The wide range of trees at RBGE means the Garden can support a great range of lichens too.
A frosty start to the Rhododendron season.
Rhododendron dauricum is one of the hardiest of the genus, flowering as January starts and often lasting well into February. Found growing through forest margins where it grows to two metres in its area of origin; through eastern and northern Asia. A semi evergreen species that is more or less deciduous with us. Pink to purple/red flowers with anthers a similar colour. The petals of delicate appearance with crinkle cut edges. However, this hardiness does not apply to the flowers which were decimated by the frosts of last week. The light green growth buds are unscathed and the tight flower buds ready to provide a show as the temperature rises.
The roots appreciate a moist cool root run and an annual top-dress with leaf mould or similar light, open organic matter.
So called, as a bunch of the stems of Ruscus aculeatus were tied together and used by butchers to sweep their wooden chopping blocks. The cladodes have a pin point end. Putting a hand into the plant will result in shredded skin so sharp are the spines. These cladodes resemble leaves attached to the main stem but are an adaptation, (the leaf is held at the base of the cladodes), in the centres of which are the flowers. The bright red, two or more seeded fruit is held here. This plant colonising a shaded border beneath a woody canopy is hermaphrodite, bearing both male and female flowers, hence the good crop of berries. Other plants may be separately male or female. A monocot, in the family Ruscaceae, the cladodes have sweeping linear veins.
Hakonechloa macra; is a perennial, clump forming, grass. It is named after Mt.Hakone, on the island of Honshu, Japan and is a monotypic genus. The foliage browns and slowly shreds and desiccates with the ravages of winter.
The winter weather also adds to the beauty; the ice crystals of a hoar frost settling on the foliage and on warmer days, shafts of low sun highlighting the leaf colour. Seed stalks still evident, of open form; draping gracefully downwards into the mass of foliage. Choose an open site and plant a group, the rhizomatous roots soon spread in fertile soil.
Reflections of a deciduous canopy
Reflective plates are set onto sections of timber from trees previously felled at the Garden. These reflect the canopy above. Quercus robur ‘Pulverulenta’ is illustrated in one of the attached images. A long lived native species of Oak beloved by insects and bird life.
Seasonal Plants of Interest, January 2012
Our native Scots Pine (Pinus sylvestris) with one of out Arboricultural Team at the top, as it is dismantles to make it safe in the Upper Woodland Garden after being damaged in the storm of the 3rd. of January.
Frost in season
The weekend of 14 – 16 January brought the coldest weather of the winter, so far, quite a shock to the system given the weather pattern this winter. Walking over ground set solid by the frost; the herbaceous plants that had not been cut back really came into their own. With the amount of moisture in the air it was a true white frost; foliage was covered in crystallised ice.
Seed heads of Iris bulleyana and the remnants of the bullet hard seed in the pods stood proud at the edge of the border and the mass of Astilbe koreana was a treat with the sun reflecting off the stems.
The aboricultural and Alpine teams tackle the removal of one of 35 large trees lost on the 3rd. Quercus robur, the Common Oak (Pedunculate Oak, English Oak) was 21 meters tall close to the mature average size of 30meters. Quercus robur is native to Asia Minor, North Africa, and the Caucasus. This plant was added to our records in 1969 as we computerised our record system, it was one of the old estate trees.
It is not just the tree that has been lost; it would have been home to many other things. The oak supports the highest biodiversity of insect herbivores of any British plant, over 400 species. The Oaks has plays a large role in folk law The traditional yule log, kept from one year to another to warm the Christmas celebrations, was traditionally hewn from oak. The old saying "Oak before ash, in for a splash...", meaning if oak buds appeared first the summer would be dry, can often be true. Until the middle of the 19th century when iron became the material of choice for building ships, it was estimated that it took 2,000 Oak trees to make a single ship!
This tree will be missed in many ways. But timber from it will be reused in the Garden.
Luckily the Nursery suffered less damage to its infrastructure than the main Garden. However, the skin of one of the largest tunnels was completely blown off. Fortunately, there was no damage to the plants inside. Many of you have asked if we have replacements for the trees that have been lost, the answers is yes we do The Nursery holds a collection of new plants from our own expeditions and those of other botanic gardens; wild origin material from Index Seminum (the name for botanic garden seed lists) and propagations from existing plants. These will form the nucleus of new plantings in the coming year, as areas are cleared.
Amongst the most interesting, Sciadopitys verticillata, is a superb conifer with unusual broad needles. Collected in Japan (Nagano Prefecture: Nagisomachi: Nagisodake: Confierous forest growing on steep ridge running north south. Dominant trees Sciadopitys verticillata and Chamaecyparis obtusa with an understory of Disanthus cercidifolius, Enkianthus campanulatus and Rhododendron degronianum Royal Botanic Garden Edinburgh Southern Japan Expedition 342. 5 Oct 2006). It may take a number of years to reach the 40meters that it is capable of in the wild.
The unfortunate consequence of fallen trees is the plants that they crush on the way down, Rhododendron beesianum, is one of may exiting new Rhododendrons that will help to re green the Wild Garden next to the Rock Garden. It was collected in China (Yunnan: Gongshan: Zizhixian: Along road from Gongshan to Kongdang. E side of Gaoligong Shan. SW facing slope. Cool temperate forest with Tsuga and Picea mixed with broadleaf evergreen trees. Growing on decomposing granite on steep slope below road. Gaoligong Shan Biotic Survey Expedition - Autumn 2002 16519. 23 Sep 2002). It has large showy heads of pink flowers in the spring and will take about 10 years to reach a mature height of 3m.
Acer heldreichii, is a medium sized tree. It has a large range from the Balkans to SE Asia. With an architectural shape and attractive foliage that gives a good display of autumn colour, it will make a good replacement tree. The plant we have is wild collected in Turkey (North-east Anatolia: A8: Artvin; above Murgul; above Damar. Ziyaretçi Das. Degraded vegetation on steep mountain slopes above copper mine, with Picea orientalis and Sorbus aucuaparia co-dominant species. Turkey Darwin Initiative 85. 27 Oct 2005).
Staff were fortunate to meet Nori Shira on a collaborative expedition in Japan a few years ago. He has sent us seed of, Magnolia stellata from Japan (Honshu: Ikawadu, Tahara-shi, Aichi Pref. Near the bottom of a north facing slope. Grows in the boggy area from the spring water, around the edge of the woodland which is a secondary forest. With Cryptomerias, Arunus japonica and Heloniopsis orientalis underneath. Colony with about 100 plants. Shira, Nori 17. 12 Oct 2007). Thought it is common in our gardens it is rare in the wild. These plants flowered for the first time in spring 2011 and they are beautifully suffuses with pink and slightly longer lasting than the white ones we usually see.
The nursery has over 3700 accessions waiting in the wings. It comes into it’s own for just such events, however, unfortunately it can not ‘stock’ the time that growth takes, that has been lost. Hopefully new expeditions will replace these plants in subsequent years. It will take many years before some parts of the Garden regain the feeling of maturity they did only a few weeks ago. (The Nursery is not open to the public).
Temperatures reaching double figures have been a daily occurrence this month and so too through December. Even the overnight minimum does not often drop below zero. Apart from this weekend which has been the coldest of the winter so far.
This has resulted in a covering through cultivated soil of seedlings that are continuing to grow. Unfortunately the culmination of this growth is flower and then seed heads. The attached image of Senecio vulgaris “Groundsel” as a mature plant, with seed at the dispersal stage, is typical of the weed flora observed in areas of bare soil.
There are benefits; the luxuriant leafy growth on Claytonia perfoliata, the “Winter Purslane” can be harvested to add a tangy taste to winter salads.
Care needs to be exercised when working through borders controlling the weed population. Emerging foliage of Eranthis hyemalis and that of spring bulbs is easily missed and a good tramping will not improve the bud development.
Do also be aware of interesting seedlings that could be lifted, potted and grow on. In the borders are examples of self seeded Thuja plicata, a western North American conifer with aromatic scent to the foliage when bruised. Seedlings of Ilex aquifolium where bird droppings have contained the seeds of Holly are also frequently seen.
New life from the January 3rd. storm
19260120 Betula utulis var. utilis
Perhaps one of the most important trees lost was part of our historic Chinese collections. The original seed for this plant came from The Arnold Arboretum in the US, the seed was collected in September 1925 by Joseph F. Rock, in China, Gansu, Upper Tebbu Country, Tatsuto, Kadjaku Valley and was received in Edinburgh 3rd. March 1926. It carries his collection number ROC 13648. It was received under the name Betula and recorded in ‘Enumeration of the Ligneous Plants Collected by J. F. Rock on The Arnold Arboretum Expedition to Northwestern China and Northeastern Tibet’. (Journal of the Arnold Arboretum 9(1): 4-27; 9(2&3): 37-125. Arnold Arboretum Library, JP. RVIIIF1-7t. 20. Rehder, Alfred and Ernest H. Wilson. 1928) as Betula albo-sinensis var. septentrionalis. It has since been verified by Dr. Hugh McAllister of Liverpool Univ. B.G. (Ness) a renowned authority on Betula as Betula utulis var. utilis. We believe that the tree has been propagated once before in the 1960s.
To rescue the tree, scion material has been taken. Betula pendula rootstocks were used and a side graft was made. The plants are on a heated grafting pipe to help make the union. The plants will then be scion rooted to remove the rootstock. We hope that the plant will be back in the garden in three to five years time.
“The worst storm for a decade” said the weather forecaster following a day of violent winds and heavy rain. Wind speeds in excess of 100mph were recorded in Edinburgh on Tuesday 3rd January. We returned from the New Year break to a Garden devastated by the storm. Prior to this the worst damage the Garden experienced was during the Boxing Day storm of 1998. Tuesday’s damage far exceeded the devastation caused 14 years ago. We have recorded 34 trees as dead and in addition noted damage to a further 40 trees. Many were uprooted including historic collections by Joseph Rock and Ernest Wilson; others have had their canopy twisted from the trunk, being deposited some distance away on other trees and shrubs causing collateral damage. The loss of mature trees reduces the age class of the living collection and the maturity of the Garden. A dismal sight to start the year but this opening up of canopy space does create planting opportunities. The fabric of the garden also suffered. The chimney stack on the former laundry building adjacent to Inverleith House was caught by the limb of X Cupressocyparis leylandii as it parted company from the main trunk smashing masonry as it collided with the building.
Glasshouses, not known for their flexibility, arched and buckled in the storm. As a consequence upwards of 600 panes of glass were lost. Many flying considerable distances causing alarm and further damage at their final resting place. The Garden remained closed on Wednesday 4th January while the initial clean up operation commenced. Drawing on the combined skills of the horticultural team the work progressed steadily with concerted effort put into opening up the roads and pathways blocked by fallen timber. Reglazing the tropical glasshouses was also of paramount importance. The holes left by the damaged glass means the required temperature levels cannot be reached and with lower temperatures forecast the need for cover is essential. The supply chain then becomes important as although we keep a quantity of spare glass nothing like the quantity required to repair this damage. The nature of the wholesale destruction means it will be a while before order is restored. The weather deteriorated again overnight of the 4th January with high winds and torrential rain; 10.4mm of rain falling in the 24hours to 10.00am Thursday 5th January.
One of the casualties was Pinus coulteri, a magnificent specimen, (meriting a mention by WJ Bean in Trees and Shrubs Hardy in the British Isles), on the west boundary, that twisted apart from the trunk at a height of 20 metres. This tree produces large cones not often seen close up. These disappeared from the fallen remains like snow off a dyke once people realised how accessible they then were. Introduced from California by David Douglas in 1832, this species has the largest cones of the genus. It is often termed “the widow maker” as the weight of a cone dropping from height can cause considerable damage. P. coulteri was named after Thomas Coulter an Irish physician who founded and then became Director of the Herbarium at Trinity College, Dublin. He also travelled to Mexico from where he made botanical excursions to the southern states of the USA. Hence his relationship with the species.
As many of you may have seen in newspapers or on the TV the RBG experienced extensive damage in the recent gales. Below are some photographs of the damage and quotes from our Regius Keeper and Curator. The good news is the Garden is open as usual! Many barriers are in place; please respect them as the danger might not be immediately obvious and some greenhouses may remain temporarily closed for reconstruction work.
Stephen Blackmore CBE FRSE. Regius Keeper & Queen's Botanist
“I carried out an inspection of the damage to glasshouses and the Edinburgh garden with David Knott yesterday. It was distressing to see how much damage has been done , not just in terms of the loss of so many fine trees but also the serious impact on the research glasshouses and the priceless collections they contain.
I was, however, amazed at how quickly order is being restored and want to thank and congratulate everyone involved – staff and volunteers – for making such an outstanding effort. I felt very proud of everyone who has made this remarkable response possible: from clearing the fallen trees, to replacing the huge number of panes of glass that were broken and to picking up the shattered pieces of glass that have been carried far from the glasshouses. A huge amount of work remains to be done, of course, but I am grateful for the extraordinary effort that has been made.
I haven’t been able to get to Dawyck, Benmore or Logan but I know that we have suffered serious damage at all of the Gardens and I don’t doubt that everyone is responding with equal energy and commitment across the organisation.
Our Royal Patron, HRH the Duke of Rothesay, has expressed his concern about the storm damage and I will be sending him an update on the situation on Monday.
The storms has been an inauspicious start to the New Year but it is heartening to see how well we can respond to such challenges.”
David Knott. Curator Living Collection
“The clear up operation from the severe weather on Tuesday is now well under way. We have lost 34 trees ,with many more requiring further investigation and work. This afternoon work on replacing the glass on the Research Block was completed. Over the weekend and well into next week work will continue replacing the glass and repairing the Peat, Rock and Front Range Glasshouses. The Temperate and Tropical Palm Houses are open. [There is also unfortunately considerable damage at Benmore, Dawyck and to a lesser extent Logan.]
However, as those of you who have ventured into the garden and seen the extent of the damage, it will take some considerable time to tidy up and make safe all areas across the garden both outside and under glass.”
The RBGE storm damage in the press
Herald the New Year
Euclinia longiflora, this tropical West African native is a deciduous small tree growing in the tropical Palm House where it appreciates a humid atmosphere. At the end of the year dropping all of its leaves and then rapidly sprouting light green prominently veined fresh foliage.
It is now flowering profusely; long trumpets of highly scented white flowers cover the plant. Internally the sessile anthers are attached directly to the inside of the corolla tube covered in yellow pollen.
For previous years' highlights during this month, see the January Garden Highlights Archive page.