As observed during July 2008
2/7/2008
Feathered edges
The Rock Garden provides many groups of interesting plants to appreciate. In full bloom just now is Dianthus spiculifolius, a tight mound of cushion forming pointed leaves with a blue sheen.
The specimens in the Rock Garden were collected in the Pirin Mountains of south-west Bulgaria, but the species is endemic to the Eastern Carpathian Mountains and now showing variation in the flower colour within the batch of plants.
The five petals emerge rolled is a swirl formation, expanding to show their common feature: the feathered edge. A slight fragrance can be detected with the nostrils close by.
This is a worthwhile member of the genus to cultivate, reliable in flower and retaining its vegetative form.
7/7/2008
Stinking woody Solanaceae
Cestrum parqui, a woody member of the family Solanaceae, is making healthy growth in the Garden. It is native to South America, from Brazil to Argentina. This specimen was collected as seed in Chile at an altitude of 1,000m on steep valley sides of the Rio Maule, where vegetation was dominated by Nothofagus species.
Sited in the Garden in the shelter of a dominant Maytenus boaria to the east and a brick wall to the north, this usually semi-hardy deciduous shrub is flowering profusely. There is evidence of winter dieback in dead shoot tips that have not flushed this year, but generally this is a healthy 4m high and broad specimen producing luxuriant growth. The wood, as it ages, resembles Forsythia with the multitudinous covering of raised lenticels.
The greenish-yellow flowers are produced in inflorescences on the current season's growth. At night they emit a smell not dissimilar to that of gloss paint drying. When trying to place the scent, do not disturb the foliage which has a pungent odour, distinctly unpleasant. The cigar-shaped buds open at the top only to display five flattened petals, leaving the long corolla intact as a tube protecting the flower parts.
10/7/2008
Striking foliage
The greatest asset of Actinidia kolomikta, a member of the kiwi fruit genus, is its leaves. The leaf colouration on young plants is not so pronounced as on an older plant which is growing in sun or partial shade, in soil where the roots can get a good deep run.
The colour of the leaf changes randomly during the growing season to deep pink or white. Some are metallic shades, but in all cases the colour only shows on the upper surface of the leaf. Beneath, the original green pigment remains with red venation.
Often starting to colour from the leaf tip back towards the petiole, some leaves will turn a completely separate colour, others only partially.
Growing on an east-facing wall of Inverleith House is the variety A.kolomikta var. gagnepainii, which was collected in Jilin Province, China, near the border with North Korea.
The vigorous shoots, when split open, reveal a chambered pithy core, brown in colour. This helps to provide flexible strength when buffeted by wind.
15/7/2008
Frontier spirit
Growing high in the Kaghan Valley of the North West Frontier Province of Pakistan is the prickly-leaved Morina longifolia. The flower spikes are populated with creamy white buds. The corolla gradually extending in a lax fashion and colouring pink with a scalloped head. These buds are all held in whorls progressing up the stem.
The leaves develop from a basal rosette and are edged with spines; these become significantly smaller at the bases of the floral whorls. At the apex of the spike these are a shade of dull red. The internodes are soft and felty to the touch in contrast to the sharp spikes.
Planted in a vantage point atop a mound in the Rock Garden, the metre-long spikes are well appreciated from below. This provides the drainage needed for successful cultivation and longevity of this perennial species.
18/7/2008
Cool and crisp as a freshly laundered white shirt
Setting a striking pose in the sunken courtyard of the Front Range Glasshouses is a mature clump of Zantedeschia aethiopica. Native to temperate South Africa, this lush foliaged fleshy rhizomed plant exudes confidence in this cool, damp and shady situation. Here it remains semi-evergreen though in a less favourable position will die back during winter.
The spathe unfurls from green to a pure white, cool to the touch, with the yellow finger-like spadix arising from the centre of the funnel. The flowers are set above the leaf growth to a height of 1.6 metres.
It is now becoming a popular house plant and many cultivars of the species within the genus have arisen in a range of colours. These are sold for interior use and the larger cultivars for garden planting.
22/7/2008
A scent of summer
Lavender is one of those plants, easily propagated, that is found in many British gardens though native to the Mediterranean. It has one drawback: as it ages the plant becomes woody and falls apart in the centre.
Semi-ripe cuttings taken during this month will root readily and make a decent replacement plant for setting out next May.
Lavandula angustifolia 'Hidcote' is a reliable, even-flowered cultivar. The tightly packed lilac flowers are set on stalks that keep the blooms an even distance above the green foliage with the classic lavender scent. The oils from lavendar plants are used in many herbal extracts and distilled as lavender water.
L. lanata, native to southern Spain, is covered with grey lambs ear foliage. Bruising the leaves releases a menthol scent. Long, gangly flower spikes reach to one metre, dividing two or three times as growth progresses.
All lavenders appreciate a dry, sunny situation with an open, free-draining soil. Where this is not provided, plant loss can occur through a wet winter.
Lavender is also a host to cuckoo spit, as seen in the attached image. This is produced by the nymph of the froghopper, a sap-sucking insect. Eggs are laid in the plant tissue in late summer and hatch the following spring. As the emerging nymph feeds on the host plant, it excretes sap which it pumps full of air. This frothy spit-like exudate protects the immature nymph from drying out. Closer investigation of the spit reveals the small green nymph.
25/7/08
Castanea sativa, the Sweet Chestnut
A dominant tree with deeply fissured and twisting bark. The mature specimen at the rock garden divides into three giant limbs at a height of two metres. The fourth, ripped off in a long forgotten storm, now produces epicormic shoots.
Passing by there is a distinctive scent given off by the flowers. The long catkin holds the male flowers; the anthers and filaments. Tucked in at the base of these are the embryo sweet chestnuts, easily recognisable as an immature shape of the prickly shelled husks holding the brown nut.
Requiring a warmer climate to fill out to edible status than Edinburgh usually provides the nuts are disappointingly empty in late August - September when the harvest occurs in its natural geographical zone of southern Europe, North Africa and Asia Minor.
An observation picked up by the Phenology team is that of the four examples of C. sativa growing in the Garden; the rock garden tree is the only one to produce male flower parts on the catkin. The prominent white anthers are evident in the attached image.
29/7/2008
Sea-washed bark
Late July sees Clethra delaveyi clothed in long racemes of scented flowers. These are held gracefully at the ends of the shoots. The fused, cupped white petals shelter the green anthers. These individually open from the base to the terminal point of the raceme in succession.
As the petals drop the prominent style is left held in the folded sepals.
This is a tall, open, deciduous shrub with dark green leaves, the under-surface lighter to grey in colour. The terminal buds are distinctive with a bulbous shape.
At this time of year, the hidden feature deep in the canopy is the sea-washed shades of brown and grey bark on the mature wood.
A native to Yunnan Province in south-west China, it has been cultivated since the early part of the 20th century when it was initially thought to be tender. The Garden's specimen was introduced from seed collected by George Forrest when travelling through the Cangshan mountains near Dali in Yunnan Province during the 1930s.
More recent collections have been made at heights of 2,700 to 3,270 metres on ridges in rhododendron forest and through mixed evergreen and low deciduous forest.