Prunus subhirtella cultivars and hybrids
While the briefness of their glory has to be acknowledged, cherries really are the hardy spring-flowering trees for temperate climate gardens. I can think of no others, quả cherry from their close Prunus relatives and some of the magnolias that even come close to rivalling flowering cherries for sheer weight of bloom and vibrance of colour.
The genus Prunus, to which the cherries, plums, almonds, apricots and peaches belong, includes around 430 species spread over much of the northern temperate regions and has a toehold in South America. Although including a few evergreen species, such as the well-known cherry laurel (Prunus laurocerasus), the genus is mainly deciduous and generally hardy to the frosts likely to occur in most New Zealand gardens.
The genus Prunus is widely recognised as being divided into 5 or 6 subgenera, though some botanists prefer to recognise these as distinct genera. The subgenus cerasus is the one to which the cherries belong. This group includes a wide variety of species, many of which are not highly ornamental. The species which are of most interest to gardeners are the Chinese and Japanese cherries, not only because they tend to be the most attractive, but also because they tend to be reasonably compact, often have attractive autumn foliage as well as spring flowers and because centuries of development in oriental gardens have produced countless beautiful cultivars.
The Japanese recognise two main groups of flowering cherries: the mountain cherries or yamazakura and the temple or garden cherries, the satozakura. The mountain cherries, which tend to have simple flowers, are largely derived from the original Mountain Cherry (Prunus serrulata var. spontanea), Prunus subhirtella and Prunus incisa. They are mainly cultivated for their early-blooming habit, which is just as well because their rather delicate display would be overwhelmed by the flamboyance of the garden cherries.
The garden cherries are the result of much hybridisation, mostly unrecorded, so we can’t be exactly sure of their origins. Prunus serrulata (in its lowland form) and Prunus subhirtella also feature largely in their background. The other major influences are Prunus sargentii, Prunus speciosa, Prunus apetala and possibly the widespread Bird Cherries (Prunus avium and Prunus padus). The result of these old hybrids and modern developments is the wealth of forms that burst into bloom in our gardens every spring.
Regretfully, that complex parentage and those centuries of development and countless cultivars combined with Western misunderstandings of Japanese names and multiple introductions of the same plants under different names has led to considerable confusion with the names of flowering cherries.
Most of the popular garden plants are lumped together under three general headings:
- Prunus subhirtella cultivars and hybrids;
- Sato-zakura hybrids;
- Hybrids no longer listed under parent species, being instead regarded as just to difficult to classify in that way.
But however you view them, flowering cherries have so much to offer that a little confusion over naming and identification shouldn’t stand in the way of your including them in your garden. And now that many of them are available as container-grown plants that can be bought in flower, it’s really just a matter of choosing the flowers you like.
Nevertheless, it’s nice to know exactly which plant you’re dealing with, so that you can be sure of its performance and size. While most of the larger nurseries and garden centres take care to supply plants that are true to type, make sure on first flowering that your cherries match their label descriptions. Misidentification, or perhaps misrepresentation, is common.
Prunus subhirtella cultivars and hybrids
Although the flowers of Prunus subhirtella are usually small and fairly simple, they appear from early winter well into spring, depending on the cultivar. Not only that, the cultivars themselves are long-flowering, often being in bloom for three weeks to a month. There are many cultivars, but most are similar to, or forms of the two main types listed below.
‘Autumnalis’ ( ‘Jugatsu Sakura’)
This is the most reliable winter-flowering form. It often starts to bloom in late April to early May and can carry flowers right through until mid September. It seldom produces a massive burst of bloom, rather sporadic clusters of flowers. This is just as well because the flowers are damaged by heavy frosts. The flowers of ‘Autumnalis’ are white to pale pink opening from pink buds; those of ‘Autumnalis Rosea’ are the same but with a deep pink centre.