Plants to look for in June

The dry, warm weather may mean that some plants will not be in flower as long as might usually be expected. These are some which have featured as previous June Plant of the Month.
Aesculus indica 'Sidney Pearce' Cornus 'Norman Haddon' Delphinium cultivar Lavendula stoechas subsp. pedunculata Piptanthus nepalensis - S Turner
Aesculus indica ‘Sydney Pearce’
The Indian horse chestnut, a very free-flowering tree, is beautifully positioned at the top of the Thompson Road drive. The white flowers, in large panicles, are blotched with yellow, turning pinky-red after a bee’s visit. It is named after a curator at Kew, where it originated in 1928. Fortunately, it does not suffer from the leaf miner which is travelling north and so damaging A. hippocastanum, the common horse chestnut.
Cornus 'Norman Haddon'
A walk along Four Seasons Garden is always rewarding, full of plant interest. At the entrance to the pavilions’ control room Cornus ‘Norman Hadden’, a lovely spreading small tree, is covered in tiny flowers surrounded by pointed creamy white bracts. These gradually turn pink; long-lasting red fruits follow in autumn. A parent of C. ‘Norman Hadden’, C. capitata, can be found by the railings at the top of the Himalayan bed to the left of the bearpit.
Delphinium cultivars
At this time of year delphiniums stand about in the garden like rockets, and a stroll down the main borders to see an enormous stand of the deep purple –blue blooms coming into flower, will not disappoint. Delphinium is a genus of 30 species in the Ranunculaceae (buttercup). It is native throughout the Northern Hemisphere, but may also be found on high mountains of tropical Africa. Most of the delphinium hybrids and cultivars we see in our gardens are derived from Delphinium elatum, which originated in Western Europe to East Asia, and were first hybridized by the firm of Kelway at Langport, Somerset, about 1875. In the 20th century more work was done by Blackmore & Langdon of Bath to produce many of the beautiful blooms we have today. The hybrids are available in doubles and singles, tall or short, from primrose yellow through cream and white, to pale and dark blue, violet-mauve, dark purple and amethyst to almost pink.
Lavendula stoechas subsp. pedunculata
One of the most interesting areas in the Garden is the Mediterranean Climate Garden (area L on map). This is mainly because the area contains numerous unusual plants, many of them only seen in cool glasshouses or in mild areas of the country. Lavendula stoechas (French lavender), has long been in cultivation, but only hardy in warm, dry gardens. The leaves are greyish; the dense flower spikes are topped with large, purple, showy bracts. The subspecies pedunculata, orginated from Spain and Portugal. It is distinctive with its heads of tiny flowers on long stalks, and topped by long ‘ears’ – leaf like bracts which look almost comical.
Meconopsis Fertile Blue Group 'Lingholm'
Meconopsis betonicifolia, the popular Himalayan Blue Poppy was known as Meconopsis baileyi for many years after its discovery in 1886. It enjoys growing in lime-free moist soil in a cool atmosphere. These requirements mean that it can be seen thriving in Scotland and Cumbria. Although the named perennial cultivars can only be propagated by division, most species are raised from seed. By far the most important cultivar is Meconopsis ‘Lingholm’ and its value was recognised in 2005, when it was awarded the RHS Award of Garden Merit. Because of its variability in colour this plant is now named within ‘The Fertile Blue Group’ together with four other cultivars. Several cultivars of blue poppy can be found in the Woodland Garden (Area Q).
Rhododendron 'Old Port' Weigela florida
Rhododendron 'Old Port'
Springtime in the Gardens always brings an enormous variety of rhododendrons into flower. They enjoy the moist, slightly acidic, fertile soil with a degree of shelter. The genus Rhododendron is one of the largest, numbering over five hundred species, and an enormous number of hybrids. This hybrid, known to be over 100 years old, exudes subtle charm: at 10ft high, its spreading dome is covered in rich plum coloured flowers with wavy lobes in dense clusters. You will find Rhododendron 'Old Port' where the Evolution and Asian gardens meet. Visit throughout the month to see a succession of rhododendrons come into bloom.
Weigela National Collection
Sheffield Botanical Gardens holds the National Collection of Weigela, deciduous shrubs in the family Caprifoliaceae. The first species to be collected, Weigela florida, was found by the Scottish plant hunter Robert Fortune in 1845. Distribution was in North China, Korea and Manchuria. Following the opening of Japan to Westerners, several Weigela species were discovered there in the 1850s and 1860s. The genus is named after the German scientist Christian Ehrenfried Weigel (1748-1831). The flowers range from white, pink, red and yellow and are borne on short lateral twigs on year-old branches. The fruit is a dry capsule containing numerous small winged seeds. The collection was set up in 1984, and continues to grow, as modern cultivars are continually being produced, initially in France and Holland, and more recently from Canada. Many of these have coloured foliage and have a dwarf habit, which is much more suitable to smaller gardens.
For more information see Weigela National Collection