my own hybrids
|My (ex)-gardens||'Park der Gärten' Germany||ASA Convention 2003||Flowershow ARS||Dutch Rhodo. Society|
|Kalmia latifolia||"Indian Summer" in Maine||wildflowers Costa Blanca||Bernhard Knorr rhodo's||Hans Hachmann Rhodo's||Joe Klimavic azaleas|
|Planting and care are the main subjects of this website. Actually we should "creep into the skin of the plants" and "identify ourselves" with them to find out what their needs are for a healthy growth and fine flowering. And as with all living creatures it depends on their specific circumstances. You find these aspects on the left side of this page. To prevent you from scrolling too much, I split up planting and care in 2 pages with repeated index. My advise is, to take your time to read these comments to help you to enjoy your plants for many years without too much work.|
Everything is connected with everything - rhododendrons, growing and
flowering fine and with the right soil and fertilizing will not easily
have diseases or pests. The more sunlight most hybrids get, the better
they will harden off with a better frostresistance.
Heavy shadow makes a rhododendron grow leggy with less flowers, but a large-leaved rhododendron does not tolerate a lot of sunlight, so the place where you plant it is very important.
If the fall season is very wet, growth can go on for a long time and the plant will not harden off as it should. Early frosts can damage the plants. Climate and how much rainfall is also important. Also with high rainfall the fertilizer will wash out, the colour of the leaves will be lighter yellowish green and the plant will have poor growth. So, the quantity of rain has a lot of consequences for the plants.
If the soil is not good for the rhodos, and the drainage is poor, the roots will rot and diseases like phytophtora will take their chance. Quality of soil and rainfall are coherent aspects.
This all does not mean that planting and care of rhododendrons and azaleas is very complicated. Certainly not if you follow some basic principles. Just read the tips and guidelines below how to enjoy these wonderful plants many years without trouble!!
photo: healthy decideous azalea
photo: mildew on decideous azalea
out a new garden means, that you can plan everything as you want. Then
it is important to consider following things:
I like winding paths with sections where I plant conifers, bamboo,
trees and shrubs, keeping in mind where to plant the rhodos and azaleas.
Where I live now, I had to consider the strong winds from the west,
which especcially large leaved rhodos don't like!! So I had to plant
trees and conifers there for wind protection. If you bought a house with
an existing garden, you have to plan where to plant rhodos and how to
improve the soil, if needed, and which plants you want to remove and
exchange with rhodos and azaleas. Then the question is, how strict you
want to do this. Firm or a bit unorganized.
The time to plant rhododendrons and azaleas is quite long, being the best
in fall and early spring. It depands also on your climate. As long as it
is not freezing or really hot in summer, you can plant. Planting material
in active growth is not advisable. So, let's say, that in climate zones
of 5 and 6 the best planting time is from September till November,
and from April. till-mid May. In the zones 7 and 8 the best time
would be October till mid-December and March till April. Planting in
warmer periods means, that you have to water more frequently. Then it is
also necessary to plant the whole rootball if any possible. Plus, that
mulching is very important in that time to prevent evaporation of the
water. Anyway, mulching is a main issue for the benifit of the plants and
After your decision where to plant the rhododendrons and azaleas you
have to take the right measures for the soil. When the soil conditions
are good already, it is a matter of digging a hole about 3 times the
diameter of the rootball and not deeper than 15 to 20 inches. It is
always good to mix the soil with all kinds of organic materials., like
shredded oak leaf mold, decomposed pine needles, pine bark etc. If you
add pure peat it must be mixed with the surrounding soil. Never plant in
pure peat - it is too acid and has no nutrients.
Rhododendrons and azaleas
require the following soil conditions:
Rhododendrons grow best in the climate zones 5 to 8. Zone 5
is -15 to -20 F, (-29C tot -23C). Zone 8 is 15 to 20 F, ( -12 tot -7C).
Here are more or less the limits. I know that in some parts
of the USA and Finnland some 'Ironclads' can be grown even in zone 4. In
Finnland hybridizers have bred Rhodos that can stand temps of zone 4 or
even 3b. Till -30 to 35 F. (= about -40C) For decidious azaleas the
situation is a bit different, they loose their leaves in fall, and
many can stand zones 5 or even 4.Native azaleas in the USA are doing
fine in some areas, not in others. I know of problems of growing the R.
occidentale in Eastern USA. (East or West - what is the Best?:-)
Evergreen azaleas can't cope with these low temps, but can stand better
high temperatures (to zone 10) than the big leaved rhodos. (see USDA
Hardiness Zones on the internet) Another thing is, that a
certain zone does not mean everything - zone 8 in the UK is very
different from zone 8 in the USA. In the Uk there are hardly such long
and hot summers as in Georgia for instance. A zone indicates the lower
limit of freezing, not (necessarily) the upper limit of the heat!
moisture, so how much rainfall and when;
A. If we have a long fall with in October and November a lot of
rain and relatively mild weather, then the rhodos don't harden off well
enough. It seems as if they think, that spring arrived already and the
sapstream starts again wilth all the consequencies when it starts
freezing suddenly! Another example: some evergreen azaleas don't grow
well in Scotland, but here they do fine. How come? In normal summers
they harden off well here in the Netherlands, but not in Scotland,
because the summers there are not warm and long enough. Some years ago
we had a warm October and I remember October 20 with 20 C, (almost 70
F). On October 30 we had frost of - 7 C (about 20 F). The results were
desastrous with a lot of barksplit, frozen flower buds and frozen
leaves, dropping of next spring. Fortunately this does not happen often.
The question can arise why some rhododendrons are cold hardy and others
not. Late spring frosts can be disastrous by killing the flowers or
flower buds. Even with very hardy rhodos. Some hybrids have an early sap
stream, others later. I don't want too many early flowering hybrids,
because there will always be night frosts and irritation about killed
flowers. Some years ago my wife Reini and I were laying blankets,
curtains and all kind of sheets etc. over early flowering rhodos, but
with our present garden of more than 4 acres and many hundreds of
rhodos, we just accept the loss of flowers.
In some garden magazines or advertisements I read that rhododendrons
should be planted in shaded locations. Well, freely speaking, this is
just nonsens. In dense shade conditions they will grow spindly and will
hardly make flower buds. This also depends of the summer heat you have.
The more bright sunlight, the more filtered light the plants require!
Especcially in early afternoon they appreciate the filtering effect of
some trees with the lower branches trimmed up. You will understand that
this is different when you compare the conditions in Scotland with the
southern states of the USA. Most of the evergreen azaleas and small
leaved rhododendrons can cope with a lot of sun, under the condition of
a moist soil!
Of course it is evident that you want to know the plant-size at maturity.
When you buy a rhododendron or azalea you want to plant them on the
right location - which mostly means the lower ones in the front and the
larger ones in the back. On the labels there is an indication on the
colours, but also the size after 10 years. So you can read f.i. 5 feet.
In general conditions this means that the rhodo or azalea will be
5 feet high after 10 years. And after reading my story above you know
also that in shady conditions with a lot of fertilizer the plant can be
substantial higher! And in full sun with little fertilizer may be 4 feet.
This is also true if you want to know the size after 25 years. And
without (heavy) pruning of course.
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