The following
calendar was produced to act as a general fact sheet and month
by month guide for the keeping and growing of Satsuki Azalea,
primarily as bonsai but also as patio /potted plants. For
a more thorough and definitive guide to Satsuki we would recommend
reading “Floral Treasures of Japan” by Alexander
Kennedy.
Please
remember that although these plants can be brought indoors
for short periods at flowering time they are outdoor varieties
Satsuki
Azaleas have been bred and selected for over 300 years in
Japan and are highly prized for their prolific and often varied
flower colours. Although single coloured varieties of Satsuki
are available the multi-coloured’s are often the most
interesting and therefore, most popular. With their small,
glossy green leaves, their quick growth and ability to withstand
pruning/shaping these plants are ideal candidates for bonsai
styling. For 11 months a year, they can be seen as perfectly
formed bonsai but then for that one special month a year they
erupt in a profusion of colour that makes this species stand
out from all other bonsai.
There is a multitude of flower types and colours available
on the thousands of Satsuki varieties available, the main
four being: Selfs-single colour, Fukurin-coloured centres
with white edges, Sokojiro-white centre with coloured edges
and Shibori-which covers all the stripped, half & half,
flecked and combinations of all these.
Of the
varieties available in the UK Kaho and Gyoten are probably
the most common. Kaho will be recognizable by its mainly white
flowers but also with pink, self’s & pink/white
stripes. Gyoten (a sport of Kaho) has mainly pink flowers
with frilly edges.
The word
Satsuki consists of two Japanese kanji characters; “Sa”,
which is an old term for five, and “Tsuki”, which
is the word for moon. Satsuki therefore means fifth moon,
in other words the fifth moon of the oriental lunar calendar.
This is equivalent to around June in our calendar and refers
to the flowering period, as Satsuki flower around late May
or early June.
There
has been a lot of discussion and debate regarding the origins
of Satsuki azaleas but they are primarily derived from just
two species, Rhododendron indicum, the “river satsuki”,
and Rhododendron tamurae (syn. Eriocarpum), known as the “round
leaved satsuki”. Some modern botanists have suggested
that other species must have been involved because crossing
wild plants of these two species does not give rise to all
Satsuki characteristics. Other experts oppose this view, pointing
out that plants found today in the wild do not reflect the
original, very diverse plant population, because plant hunters
or amateur gardeners have long since collected all unusual
and interesting wild specimens.
JANUARY
& FEBRUARY
These
are quiet months for Satsuki Azaleas, being virtually dormant
at this time of year. Older, larger trees can withstand a
degree or two of frost, but younger plants must be protected.
A cold greenhouse is ideal but if you do not have this facility
try to position trees somewhere where they receive some protection
from the worst of the wind and rain, maybe under the staging
or at the base of a hedge. In either case be prepared to provide
additional frost protection in the form of bubble wrap or
insulating fleece during cold spells.
Cold is
not the main threat to Satsuki in winter -Water logging is,
hence the need to keep trees under cover. In a greenhouse,
leave the door and roof vents open on all but the coldest
days to allow free air movement in the house. This will reduce
the risk of mildew and other fungal diseases occurring and
will also prevent temperature build up during any sunny days
we might have.
Trees
will require water through the winter period but be careful
not to over-water at this time.
The ideal
watering regime, as with all bonsai whatever the species,
is to check each plants needs individually. Many factors determine
a tree’s uptake of water.
Satsuki,
like other forms of Azalea are members of the Ericaceae family
and as such are Lime haters. If you live in a hard water area
use collected rain water if possible.
Last seasons
leaves will have fallen by now. If your trees are protected
from wind these will accumulate on the soil surface and rot.
Remove all fallen leaves, and the yellowing ones still attached
to the tree. You may well be able to see the signs of growth
appearing around the base of flower buds. These will produce
this years shoots and on a healthy plant, there could be anything
up to five around each bud.
MARCH
Plants
over-wintered under cover will start showing signs of growth
this month. New shoots will be seen emerging mainly from around
the base of the flower buds but depending on the vigour of
the tree shoots could be found anywhere on the trunk and branches!
Trees can be brought out from cover on mild, sunny days but
do not be tempted to leave out overnight as a frost could
damage new shoots.
There
are two periods per growing season for re-potting Satsuki,
one just after flowering in late May/early June or now in
late March. If growing-on young, untrained material, now is
ideal as it will allow a full season, unchecked growth. If
it were rapid, growth you are after it would be beneficial
to remove all, if any flower buds.
Feeding
should also begin this month on young and older trees alike.
Specimen plants should be fed regularly from now until bud
burst to help strengthen them prior to flowering.
March
is also a good time of year for refinement wiring of young
growth in foliage pads. Heavy wiring to shape trunks and branches
is best left until the autumn.
‘Kanuma’,
a form of Japanese soil is often said to be the ideal potting
medium for Satsuki Azaleas. The will however grow in any lime
free compost mix.
APRIL
This is
the month when Satsuki’s really begin to wake up after
the winter’s rest, particularly if they have been over-wintered
under cover. Main areas of growth are as mentioned above but
also “sucker” like growths are commonly seen growing
from roots at or just below the soil surface. Unwanted growth
can easily be rubbed off but before you do have a good look
at the design of the tree first to assess if any of these
shoots might be in just the right place to develop into new
branches. On strong growing varieties of Satsuki up to five
or more shoots will grow from around the base of flower buds
so to stop the flowers being swamped by foliage later in the
year it is best to thin these out to two, preferably horizontal
shoots either side of the bud.
Continue
feeding throughout this month using fertilizers specially
formulated for ericaceous plants. As an alternative, there
is an excellent fertilizer from Japan called “Biogold.”
This comes as small cubes that you press into the surface
of the soil. Unfortunately, this is only available from Bonsai
Nurseries.
Trees
still under cover can be brought out now but be careful of
sudden frosts. They are unlikely to kill a tree
but they can damage flower buds.
MAY
Flower
buds will be swelling nicely now, in fact some will be showing
colour or even be open depending on weather conditions and
how the plant has been over wintered. Strong growing shoots
from the base of the buds should be trimmed back to allow
the flowers space to open. Because of the prolific number
of flowers, a tree can produce, to reduce stress it is good
practice to reduce the number by anything between 30 –
50%. On a show tree, this can be achieved by removing most
of the flowers from the back. On young plants, being grown
on it would be advisable to remove all the flowers to encourage
maximum growth.
Stop feeding
now. This will encourage a longer flowering period. Providing
some kind of temporary shelter to protect the buds and flowers
from rain will stop them from discolouring. For the same reason,
be extra careful when watering. This temporary shelter will
also serve as a sunshade to help stop flowers fading prematurely.
This is a busy time in the growth pattern of Satsuki and demand
for water will increase
accordingly.
JUNE
Remove
all flower heads. Although this can be a tedious, time consuming
job it is important to prevent the production of seed, which
puts undue stress on a tree at a time when it needs to recover
from the rigours of flowering. New growth slows for a short
period after flowering and this is an ideal time for repotting,
wiring and pruning/trimming to shape. Feeding can re –commence
once flowering has finished but wait a few weeks if trees
have been repotted. Likewise, care should be taken not to
over water newly repotted trees. As mentioned previously,
Satsuki, like all other azaleas and rhododendrons, produce
a profusion of new shoots from the base of old flower buds.
With Satsuki, it is best to remove all unwanted shoots leaving
just two, one either side of the bud. These are then trimmed
back to two pairs of leaves.
JULY
Some late
flowering varieties will still be in flower this month. Allowing
trees to flower this late in the year can have a long-term
detrimental effect on the plants health. Hard as it seems,
all flower buds/flowers should be removed, especially if the
tree is about to be repotted. Leaving flowers on this late
will weaken the tree at a time when it should be producing
next year’s flower buds. A short time after flowering
is over a second spurt of growth occurs.
Satsuki
are relatively pest free but keep a watch out for greenfly,
red spider mite and vine weevil.
Satsuki’s
will tolerate or even appreciate a position in full sun but
will tolerate semi-shade.
AUGUST
All repotting
and pruning should be finished by now. From now on Satsuki’s
should be allowed to build up strength for the winter and
it is also during this period that next years flower buds
are produced. Continue regular feeding and watering.
This year’s
shoots will still be extending but slowing down now. These
shoots will carry next year’s flowers. Any shoots that
were trimmed earlier in the season might well be showing secondary
shoots growing from them. If these are strong enough they
will also produce flower buds. Some light trimming and removal
of unwanted
growth can still be carried out but remember that trimming
at this time of year will mean removing flower buds.
SEPTEMBER
Pretty
much as per August. Growth will be slowing right down now;
subsequently watering needs will be less however continue
feeding.
OCTOBER
As previously
described, Satsuki have two distinct growth periods, one in
the spring prior to flowering and again after flowering. The
leaves produced in the first flush of growth will start changing
colour this month and eventually fall. Unfortunately there
is no spectacular autumn colour display like many other Bonsai
subjects, just a change from Green to Yellow although I have
seen the leaves of red varieties turn to a shade of red like
a maple, but this only happens occasionally.
The second flush of growth in the summer, mainly clustered
around the flower buds, will remain on throughout the winter.
Remove all leaf litter from the surface of the compost.
NOVEMBER & DECEMBER.
Generally
as October. Late October/early November is the time of year
to start preparing winter quarters for trees. A cold greenhouse
is ideal but any cover that will offer some protection from
heavy frosts and in particular, constant, heavy rain will
do. Remember that Satsuki’s are not deciduous so a dark
shed or garage will not do! During the winter try to provide
as much ventilation and light as possible to avoid mildew.
Water as required -do not over water.
