Flowering Cherries
Flowering cherries: 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, apart 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:
1. Prunus subhirtella cultivars and hybrids;
2. Sato-zakura hybrids;
3. 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.
Plants
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.
'Pendula' ('Ito Sakura')
Prunus autumnalis tends to have weeping branches and 'Pendula'
is a cultivar that emphasises this feature. Its flowers
are usually pale pink and open in late winter to early spring.
'Falling Snow' is a cultivar with pure white flowers, while
those of 'Rosea' are deep pink.
Sato-zakura hybrids
'Fugenzo' ( 'Shirofugen' )
'Fugenzo' was one of the first, if not the first, Japanese
cherry to be grown in European gardens. It 's origins can
be traced back to at least the 15th century. Its flowers
are white to very pale pink, opening from pink buds, and
when fully open how two conspicuous green leaf-like pistils
in the centre of the flower.
'Taihaku'
'Taihaku' , also known as the great white cherry, has white
flowers up to 5cm across. It grows to at least 8m tall with
a wider spread and its flowers open at the same time as
its bronze foliage expands, making a pleasant contrast.
Thought to have been lost to cultivation, this cultivar
was identified in Sussex garden from an old Japanese print.
'Ukon'
Although 'Ukon' mean yellowish, this cultivar has very
distinctive pale green flowers and is one of the few unmistakable
cherries. Its foliage develops purplish tones in autumn.
The unusual flower colour contrasts well with the likes
of 'Sekiyama'.
'Amanogawa' ('Erecta')
'Amanogawa' grows to around 6m tall, but only around 1.5m
wide, and has pale pink single flowers with a freesia-like
scent. It blooms in mid-spring and in autumn the foliage
develops striking yellow and red tones.
'Shogetsu' ('Shugetsu', 'Shimidsu-zakura')
'Shogetsu' flowers late and produces pendant clusters of
white, double flowers that open from pink buds. The flower
clusters are up to 15cm long, which makes a tree in full
bloom an arresting sight, especially considering that 'Shogetsu'
is not a large tree and that its weeping habit means it
can be covered in bloom right down to the ground.
'Sekiyama' ('Kanzan')
Certainly among the most popular cherries and most often
sold under the name 'Kanzan', 'Sekiyama' has a relatively
narrow, upright growth habit when young but eventually develops
into a spreading 12m tall tree. Its flowers, which are pink
and very fully double, are carried in pendulous clusters
of five blooms. They open from reddish-pink buds. The foliage
has a slight red tint.
'Ariake' ('Dawn', 'Candida')
This cultivar grows to about 6m tall and flowers in spring
as the foliage develops. The young leaves are a deep bronze
shade that contrasts well with white to very pale pink flowers.
'Kiku-shidare' ('Shidare Sakura')
'Kiku-shidare' is similar in flower to 'Sekiyama', but
it has a weeping growth habit. It is a small tree and is
often smothered in bloom from the topmost branches down
to near ground level. The flowers can each have up to 50
petals.
'Pink Perfection'
'Pink Perfection' was introduced in 1935 by the famous
English nursery Waterer Sons and Crisp. It is a probable
'Sekiyama' × 'Shogetsu' hybrid and has flowers that show
characteristics of both parents; the clustered blooms of
'Shogetsu' and the pink of 'Sekiyama'. The flowers are very
fully double and the young foliage is coppery.
'Kofugen'
'Kofugen' has graceful semi-weeping branches and a fairly
compact growth habit. Its flowers are not really single
but semi-double, though the two whorls of petals are flat
rather than ruffled, so the effect is not that easy to see.
'Shirotae' ('Mt. Fuji') This beautiful tree has a spreading
growth habit that in the best specimens shows distinctly
tiered branches. Its flowers, which are white and semi-double
on mature plants, start to open before the foliage expands.
They are pleasantly scented.
'Takasago'
Although possibly a Prunus × sieboldii cultivar, 'Takasago'
is now more widely listed under the satozakura cherries.
It bears clusters of semi-double pink flowers with bronze-red
new foliage.
'Ojochin' ('Senriko')
This tree, rather squat when young, but eventually 7m tall
bears single white flowers in such profusion as to give
the impression of double blooms. Opening from pink buds,
the flowers are up to 5cm in diameter and among the later
to bloom. 'Ojochin' means large lantern, which aptly describes
the shape of the flowers.
Other hybrids, species and their cultivars
'Accolade'
One of the most popular of all garden cherries, 'Accolade'
is a Prunus sargentii × Prunus subhirtella hybrid that develops
into a flat-topped small tree. In spring it is smothered
in pendulous clusters of large, bright pink, semi-double
flowers.
Yoshino cherry (Prunus × yedoensis)
Well-known as an avenue tree, this Prunus subhirtella ×
Prunus speciosa hybrid is smothered in white to very pale
pink blooms in spring before or as the new leaves develop.
When the flowers are spent they form drifts of fallen petals
around the base of the tree. There are several cultivars,
such as the pink-flowered 'Akebono' The pale pink 'Awanui'
and a weeping form ('Shidare Yoshino' or 'Pendula').
Taiwan cherry (Prunus campanulata)
The Taiwan cherry is valued for its early-flowering habit
and fiery autumn foliage. The flowers, which are usually
a vivid deep pink, are heavy with nectar and very popular
with birds. Taiwan cherry is rather frost tender, though
once established it grows well in most coastal areas.
'Okame'
Introduced in 1947 by the British authority Collingwood
Ingram, 'Okame' is a hybrid between the Taiwan cherry and
the Fuji cherry (Prunus incisa). It is usually quite hardy,
though this appears to be variable, and it flowers heavily
in early spring. The blooms open in late winter to early
spring before the foliage develops and are a bright soft
pink. 'Pink Cloud' is a similar though more compact cherry
raised by Felix Jury.
Himalayan hill cherry (Prunus cerasoides)
This species is rather frost tender, especially when young,
but is a beautiful tree where it grows well. Not only does
it produce pink flowers in winter, when little else is in
bloom, it has attractive banded bark and the unusual habit
of shedding its foliage in late summer then producing new
leaves before winter. The variety rubea has deeper pink
flowers in spring.
Cyclamen cherry (Prunus cyclamina)
Flowering on bare stems in early spring, the cyclamen
cherry is a hardy small to medium-sized tree from central
China. The flowers, which are rose pink, are followed by
bronze new growth that retains its colour for some weeks
before greening. The leaves fall late in autumn and often
colour well.
Sargent's cherry (Prunus sargentii)
This large and very hardy Japanese species is probably
best known as one of the parents of the very popular hybrid
'Accolade'. It can grow to as much as 18m tall and will
withstand at least -25°C. Its 3 to 4cm wide, bright pink
flowers are complemented by red-brown bark.
Kurile cherry (Prunus nipponica var. kurilensis)
Usually little more than a large shrub, this Japanese cherry
can reach 6m tall under ideal conditions. The flowers, which
are soft pink and open from early spring, are backed by
red sepals that hang on for a while after the flowers have
fallen, thus prolonging the spring colour.
Prunus × sieboldii
This hybrid has given rise to several popular cultivars.
The original cross is a slow-growing small tree with semi-double
3 to 4.5cm wide flowers in spring. The new stems are often
very glossy.
Cultivation
Flowering cherries are largely undemanding plants that
thrive in almost any well-drained soil. For the best display
of flowers they need to see at least half-day sun and if
sheltered from the wind, the blooms and the autumn foliage
will last far longer than if exposed to the full blast of
the elements. Cherries are often seen growing as lawn specimens,
but they can be planted in shrubberies, borders or small
groves. By choosing a selection that flowers in succession,
it's possible to have bloom from mid-winter to early summer.
Cherries are natural companions for azaleas and rhododendrons,
and can be used to beautiful effect as shade trees for the
smaller varieties of these or to shelter a collection of
woodland perennials such as primroses and hostas. Japanese
maples also blend well with cherries and they can combine
to make a brilliant display of autumn foliage.
Pruning
Flowering cherries seldom need major pruning once established.
Young trees can be lightly trimmed to develop a pleasing
shape and mature plant may be kept compact by tipping the
branches, otherwise just remove any vigorous water shoots
and suckers that sprout from the rootstock. Make sure that
any pruning is done in summer to prevent infecting the trees
with silver leaf fungus (Chondrostereum purpureum). Although
this disease is present throughout the year, cherries are
most resistant to it in summer.
Pests and diseases
Apart from the already mentioned silver leaf, there isn't
really very much that goes wrong with flowering cherries
that can't be tolerated. Sawfly larvae (peach or pear slug)
sometimes cause damage to the foliage, and older plants
sometimes suffer from dieback in their older branches, but
these are seldom serious problems. The dieback is sometimes
the result of Armillaria, so it may be advisable to insert
some of the now readily available Trichoderma dowels into
the trunks of any older cherries to prevent the problem
developing.
Propagation
Virtually all of the fancier flowering cherries sold for
garden use are budded or grafted, usually onto Prunus avium
stocks. Although few home gardeners attempt them, these
processes are not difficult. Budding especially, is straightforward
and is carried out in exactly the same way as budding roses.
Species, including the standard Prunus avium stock, can
be raised from seed or from softwood cuttings taken in spring
or early summer. The seed should be removed from the fruit
by soaking for few days until all the flesh has fallen away.
It is usually best to simulate winter conditions by chilling
the seed for a few weeks before sowing.
Graft height
When buying flowering cherries you may be faced with a
choice of graft height. Which you choose largely depends
on the cultivar and the type of growth best suited to your
garden. With weeping cherries choose the highest graft possible
(usually 8ft [2.4m]), to allow the maximum length of flowering
branch. Upright cultivars like 'Sekiyama' are best grafted
near ground level so that their erect habit has a chance
to develop properly, while graft height in not that important
with bushier trees. The important thing to remember, particularly
with high grafted plants, is that the main stem will not
gain much height from the grafting point. The stems of a
weeping cultivar may grow up before arching down, thus adding
some height, but if you choose too low a graft that won'
t make much difference. Low-grafted weeping cherries are,
however, ideal for large tubs where they can be kept trimmed
to shrub-like proportions.
I am a garden book author and horticultural photographer
based in Christchurch, New Zealand. I run a stock photo
library called Country, Farm and Garden (http://www.cfgphoto.com).
This article may be re-published provided this information
is published with it and is clearly visible.
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