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Growing and Caring
for Rhododendrons and Azaleas
by Michael J. McGroarty -
www.freeplants.com
Azaleas can be either evergreen or deciduous. Deciduous
Azaleas are known as Mollis or Exbury Azaleas. They bloom in
the early spring with vivid orange and yellow colors. They
can be grown from seed if the seeds are collected in the
fall and sown on top of moist peat at about 70 degrees F.
Evergreen Azaleas are known as broad leaf evergreens because
they are do not have needles. They bloom later in the
spring, and are usually propagated in the fall over bottom
heat, discussed in detail at Rhododendrons are also broad
leaf evergreens and are also propagated over bottom heat in
early winter.
The best time to prune Rhododendrons and Azaleas is in the
spring right after they bloom. These plants start setting
next years flower buds over the summer, so late pruning will
cost you some blooms next year, so get them pruned as soon
as they finish blooming. It’s also a good idea to pick off
the spent blooms so the plants don’t expel a lot of energy
making seeds, unless of course you’d like to grow them from
seed. But keep in mind that they don’t come true from seed.
Seeds from a red Rhododendron are likely to flower pale
lavender. Cuttings insure a duplicate of the parent plant.
How do you prune Rhododendrons and what does pinching a
Rhododendron mean? These are frequently asked questions.
Pinching is a low impact form of pruning that is very
effective for creating nice, tight full plants when you are
growing small plants from seeds or cuttings. Typically a
Rhododendron forms a single new bud at the tip of each
branch. This new bud will develop into another new branch,
another bud will form and the process will continue. If left
alone this will produce a very lanky plant with a lot of
space between the branches forming a very unattractive
plant.
So if you are starting with a plant that is nothing more
than a rooted cutting all you have to do is pinch off this
new growth bud as soon as it is about 3/8” long. Just grab
it between your fingers and snap it completely off. When you
do this the plant usually responds by replacing that single
bud with two, three, or even four new buds in a cluster
around the bud that you pinched off. Each one of these buds
will develop into branches and eventually a single bud will
appear at the tip of each of these branches, and of course
you should come along and pinch each one of those off
forcing the plant to produce multiple buds at the end of
each of these branches.
The more often you pinch off these single buds, the more
branches the plant will form, making a nice, tight, full
plant. This is especially helpful with young plants such as
rooted cuttings or young seedlings.
But what about larger plants, how do I prune them? I prune
mine with hedge shears!!! I just have at it and trim them
like I would a Taxus or a Juniper, and guess what? The
result is a very tight compact plant loaded with beautiful
flowers. My Rhododendrons are so tightly branched that you
can not see through them, and that is the result of vigorous
pruning with hedge shears. Sure you can use hand shears, and
you’ll have a nicer plant because of it, but I just use the
hedge shears because that’s the tool that I happen to have
in my hand as I am going by.
Keeping Rhododendrons and Azaleas healthy and happy is a
simple as understanding what they like. First of all they
like to grow in a climate that suites their tastes. Many
varieties of both don’t like it in the north, and to prove
the point they will up and die as soon as extreme cold
weather hits. Buy plants that are known to be hardy in your
area.
Here in zone 5 (northern Ohio) the following Azaleas seem to
do well. Hino Crimson (red), Stewartstonia (red), Herbert
(lavender), Cascade (white), Delaware Valley (white), and
Rosebud (pink). Hardy Rhododendrons include Roseum Elegans
(pinkish lavender), English Roseum (pinkish lavender), Nova
Zembla (red), Lee’s Dark Purple, Chinoides (white), and
Cunningham’s (white).
How should you fertilize Rhododendrons and Azaleas? These
broad leaf evergreens are laid back and like to take it slow
and easy. Do not fertilize them with quick release nitrogen
fertilizers, it could kill them. Instead give them an
organic snack, like Millorganite or well rotted cow manure
or compost. Millorganite is an organic fertilizer made of
granulated sewage sludge.
No it doesn’t smell any worse than other fertilizers, and
plants like it because it is plant and soil friendly. It
won’t burn the plants, and it actually reactivates the
micro-organisms in the soil. That’s a good thing. Most full
service garden centers carry Milorganite.
A long time ago somebody let the word out that Rhododendrons
are acid loving plants, and people are always asking me if I
think their struggling Rhododendron needs more acid. The
answer is no. Your struggling Rhododendron probably needs a
great big gulp of oxygen around it’s root system.
Rhododendrons do not like wet feet. They don’t even like
high humidity let alone wet soil around their roots. They
like to be high and dry, and like an unobstructed flow of
oxygen to their roots. You can accomplish this by planting
them in a bed raised at least 10” with good rich topsoil.
They will be smiling from branch to branch.
A few years back my friend Larry and I had several hundred
small Rhododendrons that we were going to grow on to larger
plants. We planted most of them in Larry’s backyard which is
fairly good soil, but a little sticky. We didn’t have room
for all of them so we planted the last 105 down the road
from my house in a field we were renting. (Never heard of
anybody renting a field? You should get out more.)
This location had absolutely no water for irrigating and the
soil was very dry and rocky. Other plants at that location
often struggled during the dog days of summer due to the
lack of water, but those Rhododendrons were as happy as pigs
in mud. They out grew the ones at Larry’s house by twice the
rate and we sold them years earlier than the others.
My point? Rhododendrons don’t like wet feet. They do well in
the shade, but contrary to popular belief they do even
better in full sunlight.
Michael J. McGroarty is the author of this article. Visit
his most
interesting website, http://www.freeplants.com and sign up
for his excellent gardening newsletter, and grab a FREE copy
of his E-book, "Easy Plant Propagation" |
