Salvia - More Ornamental Forms
Over the last few months we have looked at the culinary forms of Salvia, the large growing ornamental forms and the popular smaller species and cultivars. This month I want to cover a couple of the more difficult to grow and unusual forms.
First are the clumping forms like Salvia nemorosa and its hybrids S. x superba and S. x sylvestris. These plants form tight clumps with masses of attractive violet to purple-pink flowers that are hardy quite cold temperatures. They are very popular in the UK where they have been grown for over 200 years. S. nemorosa comes from eastern Europe and western Asia. They all have sessile basal leaves and lanceolate leaves on wispy stems. They are usually propagated by division or stem cuttings although the plants produce relatively few making them hard to propagate in large commercial quantities. They do germinate form seed but few of the cultivars come true to type. Some of the best garden plants in the UK come from this group, including ‘Ostfriesland’, ‘Superba’, ‘Mainacht’ and ‘Rose Queen’.
All of the above varieties are relatively small to medium growing shrubs to around 50-75cm. Most flower in late summer and early autumn and many will flower in their first year. Although small growing plants they still require full sun and well drained soil. The next group are the rosette forming varieties. There are a dozen or so species including the parent of several attractive cultivars; Salvia pratensis and the ancient Mediterranean species Salva sclarea. The latter has been used in medicine and aromatherapy since the ancient Greeks. It is the source of one of the more popular essential oils and has the common name Clary Sage. This is supposed to come from the way the seeds of this plant were used to help ‘clear’ the eye.
Clary Sage is a tough plant that is hardy to quite cold conditions and has become naturalised in much of UK and northern Europe. It has large sessile basal leaves and tall stems topped by colourful flowers and bracts. Growing to over a metre in height it is an excellent plant for the traditional cottage garden.
Salvia pratensis is a similar plant with a tight basal clump of large sessile leaves and 60cm tall flowering stems. It is unusual in the Salvia world as it will flower well in early spring. The specific name, pratensis means growing in meadows. It is found across most of western Europe in open grassy meadows. It needs full sun and moist but well drained soil. The flowers range from deep pink of ‘Rose Peaks’ to the dark blue of ‘Tenorii’.
To demonstrate how variable the genus is you only need to look at the two rosette forming species; S. argentea and S. aethiopis. They are desert like in that they can tolerate quite low temperatures but do not like water. S. argentea has nice white flowers on long stems (to 90cm) in late spring and early summer. S. aethiopis has similar flowers but the stems only grow to 60cm in mid summer. These two varieties are available in the odd specialist or old fashioned plant nursery. They have large foliage with fine white hairs that give them an attractive silver grey appearance. Indeed these two are generally grown for the foliage instead of the flowers. Both are better suited to pots or rockeries as they do not like wet feet or foliage and are banquets for slugs and snails. As pot plants they make an attractive display in the nursery.
The final group of plants are a relatively new addition to the general nursery trade. Some have been around in the collector’s gardens and some are new to Australia. These are the north and east Asian forms from China and Japan. They are true woodland plants and prefer moist, shady locations with winter mulch. Like most other Salvia they do like well drained soil. Three of these are S. koyomae, spreading plant with yellow green leaves and soft yellow flowers, S. nipponica, small shrub with lime green foliage and yellow flowers and Salvia yunnanensis, a medium growing shrub with dark, almost black flowers from the southern provinces of China. Some nurseries call this the Chinese Salvia but there are numerous Salvia from China so it is a misleading name. The first two come from Honshu in Japan. A small region with some very unusual plants.