Observed during May 2009
1/5/2009
A wall of colour
Outstanding. Just one word that captures the quality of the Rhododendron display this year. Previously I mentioned a subspecies of Rhododendron arboreum. A hybrid affiliated to this species, R. aff. arboreum hybrid produces a wall of colour covered in mauve trusses of bloom to a height of five metres. Looking behind the wall of vegetation reveals a two metre layer.
The plant at one stage, several years previously, becoming top heavy, collapsing, then sending up skywards shoots that have matured into the growth seen today.
Next to this plant is a more delicate flower, pink in bud to unfurl white, R. bureavii from Northern parts of Yunnan Province, S.W. China.
The leaves of this species also attract attention. The reverse is covered evenly and thickly in brown indumentum.
The flowers of R. yunnanensis (also from S.W.China and N.E. Myanmar) release a heady perfume. This in itself is worth visiting the Garden for. The area around this plant is saturated with this most compelling scent.
Representatives of the collecting prowess of E.H. Wilson and Joseph Rock are worth hunting for. The blue of R. augustinii ssp. augustinii is cascading through the mature plants. Look into the individual flowers of Joseph Rock's, R. augustinii ssp. hardyi. White petals with the top inner lobes marked decisively green. These spatterings of colour are unusual and worthy of comment. Designed to entice pollinators to the flower, in both, the flower parts flail out wildly.
So, for a visual feast of walls of colour, banks of perfume and intricacies of design; walk through the north or east gate and enjoy the experience.
5/5/2009
Paeonia with a problem
Paeonia mascula; with a wide geographical range; Mediterranean to S.E. Asia, this herbaceous species produces carmine red flowers that are stuffed full of yellow anthers. 
A worthwhile member of the genus to cultivate. Depending on provenance flower colour can range white - pink - red. There is wild collected material from Cyprus represented in the collection.
Paeonia wilt, Botrytis paeoniae, can be seen in the attached image. Grey mould colonises soft brown areas of rot which occur at the base of the stems. This grey mould will then gradually colonise all plant surfaces. Remove and ideally burn all infected vegetation, ideally scraping off the soil in the area where the spores may have dropped to. In autumn good hygiene will prevent the disease from carrying through to the following year.
8/5/2009
Iris's handkerchief
Iris iberica var. elegantissima one of the showiest of the Oncocyclus group of Iris. This naturally occurring variety is found in N.W. Turkey and into neighbouring Iran.
The seed parent of this bulbous Iris was found growing on dry rock strewn slopes at 2200m near Erzurum in Turkey. In full bloom the white standards resemble handkerchiefs (cotton of course) strewn about.
These broad creamy white standards are c. 100mm across. Purple streaking and mottling at the base develops into striations then a pepper dusting around the centre tip.
The two falls drop vertically from the centre of the flower. These are scallop shell shaped with white markings on dark mauve colouration. This is a must see plant displayed in the alpine house and with a second bud yet to open, extending the opportunity well into next week.
The centre is a dark mass in three sections, the combination of colour shades and markings throughout the flower; all to attract pollinating insects.
12/5/2009
Intoxicating scent seeking wall space.
Elytropus chilensis a woody evergreen almost unnoticed as you walk through the Chilean plant collection to the north of the Front Range. Flowering profusely tucked beneath other shrubs but in desperate need of a wall to climb. The long scandent growth is thriving in this shaded ground hugging situation to the self satisfying point of producing flowers at each leaf axil of the previous year's growth. In Chile it grows in the shade of rain forest canopy on the sides of the coastal mountains up to the edge of the tree line at c. 2000 metres.
The small leaves have a glossy upper surface and are set opposite each other on the stem. The flowers hang down from these axils, five petalled, tinted pink on the lower inner surface. The scent drifting out is dismissed at first, but there is something intoxicating about the intensity of the smell. Well worth the walk to the north of the Front Range to sniff test.
From the microscope images the anthers are covered in minute bristle like white hairs, a secondary group of hairs can be seen at the base of the petal chamber. Notice the globules of nectar which are contained within the base of the flower parts. Observe the translucent, almost ice crystal, colour change at the tip of the anther. The fascinating detail and intricacies of design within the plant kingdom are revealed through the lens on the microscope.
15/5/2009
Visible from space
Descending into Edinburgh airport and picking out landmarks is generally the way to pass the time in anticipation of landing in the capital.
On a return flight our Director of Horticulture anxious to confirm the Garden was still here was nonplussed to observe a mass of yellow at its centre. This is the young foliage of Quercus rubra "The Red Oak", introduced from Eastern North America in 1724.
The tree is set to the north east of Inverleith House and the broad spread canopy of foliage visible from many points in the Garden. There is a cultivar 'Aurea' and this may be a representative of it. As the season progresses the foliage turns green and as a finale produces desirable autumn colour.
19/5/2009
Salad days
Magnolia acuminata, also known as "The Cucumber Tree". It takes this common name from the shape and appearance of the fruit which swells to resemble a cucumber after petal fall. The flowers are not big and blousy as in other members of the genus but merge with the spring foliage. There is a green metallic sheen to them in the sunshine. With a sweet, honeyed fragrance the flowers sit upright on the previous year's growth.
A native to eastern North America where it makes a broad specimen as a large forest tree to 30 metres height. In Canada it is recognised as endangered.
As a topical reminder to keep fresh salad appearing on the kitchen table; remember to keep up with the sowing of small amounts of seed frequently at this time of year. No amount of salt on a woody radish will improve its texture!
26/5/2009
The Himalayan Blue Poppy
A new planting of Meconopsis Hybrids can be seen in the woodland garden, one of the best being M. 'Slieve Donard'. This hybrid has an Edinburgh city pedigree dating from about 1935. Dr. Curle a former Director of the Royal Scottish Museum used M. grandis and M. betonicifolia as breeding parents; 
raising many seedlings. Some of these found their way to the long gone Slieve Donard Nursery, Co.Down, Northern Ireland. Here they were bulked up and the Slieve Donard form selected out and introduced to the trade. With us; flowering commenced in the middle of the month and has now reached its peak.
More detailed information on the nomenclature of the genus can be found at the Meconopsis Group website. The group are currently undertaking a revision of the genus, placing M. 'Slieve Donard' in the Infertile Blue Group.
As a contrast; planted near this group in the woodland garden is M. 'Marit' defined by its large white petals. Both cultivars mentioned send up flower spikes from a basal rosette of leaves. The clumps require splitting and dividing every 3 - 4 years. Appreciating a cool moist root run the addition of composted organic matter at planting will ensure sturdy growth and reliable flower production.
Established plantings can be seen at Dawyck Botanic Garden where it has long been planted along the banks of the Scrape Burn.
29/5/2009
Pin ‘n Pod
Foliage to appreciate in a woodland border is how I would describe the leafy growth produced by these two memorable Rodgersia species. Rough and robust. The images show the variable shades of green and bronze taken by these leaves.
R. pinnata with almost pinnate leaves. The 1990 collection made on the Chungtien Lijiang Dali Expedition (CLD) to Yunnan Province, China has green leaves. Found growing at 3430m amongst Rhododendron on a steep hillside near Longquan Peak. Yet a 1961 accession to the Garden is decidedly purple. The cultivar ‘Irish Bronze' has foliage slower to develop but with a uniform deep purple colour. Flower spikes have good structural form and are covered in small pink flowers.
The favourite has to be R. podophylla; native to Japan and Korea with large palmate leaves. Strong uniform growth to 1.3m. This introduction was collected by Yuji Kurashige at 1200m in Honshu Province, Japan. If you have a soil that retains moisture in a shaded area of the garden then this is the one to prepare the ground for. Add organic matter at planting and once established top dress annually. The flower spike pushes out above the foliage to 1.6m gradually expanding to pagoda like form.
For previous years' highlights during this month, see the May Garden Highlights Archive page.