Caring for Rhododendrons and Azaleas
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
are known as broad leaf evergreens because they do not have needles.
They bloom later in the spring, and are usually propagated in the
fall over bottom heat. Learn more about propogation
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 year's flower buds over the
summer, and 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 ensure 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
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
cannot 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.
Rhododendrons and Azaleas healthy and happy is as simple as
understanding what they like. First of all, they like to grow in a
climate that suits 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
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 broadleaf 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 Millorganite.
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 its
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 outgrew the ones at Larry's house by
twice the rate and we sold them years earlier than the others.
Rhododendrons don't like wet feet. They do well in the shade, but
contrary to popular belief they do even better in full sunlight.
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