Why won't my Rhododendrons bloom?
kjkrout
they were about 45 years old, tall, scraggly, and bloomed. I clipped
them all the way back and got a wonderful amount of new growth. I kept
them watered and fertilized with Rhode fertilizer and we haven't had a
bloom since 1996! I stopped fertilizing two - three years ago and
stopped trimming them last year. Still no blooms. What's happened?
KrisHur
branch. After pruning, it takes a season or two for them to grow new growth,
then set a bud on it. They may have developed buds over this season, if not
they should produce buds next year. Go look at the tip of the branches,
there should be a little cone, that's the bud for next year's flower. BTW,
except for rejuvination cut backs one should not prune a rhodie, if you
must, do it after flowering.
Excellent rhodie care site:
http://www.users.fast.net/~shenning/rhodyho.html#anchor291256
Good luck!
"kjkrout" <kjk...@home.com> wrote in message
news:3B84ABB0...@home.com...
TOM KAN PA
tom kan pa
Stephen M. Henning
Failure to set flower buds may be a sign of too much health and vigor in
a plant. One solution my be to prune the roots by cutting around the
plant with a spade or moving the plant. This will check foliage growth
and encourage production of flower buds. Application of nitrogen rich
fertilizers are the main cause of vigor which suppresses flower bud
production. Deadheading flowers as soon as they wilt can promote flower
bud production. Too much shade, a cool wet summer, or inadequate
phosphorus or potassium in the soil may suppress flower bud production.
There are a number of other reasons for a lack of flowers. The effect of
each variable depends upon the variety of the plant. The effects include:
PRUNING. The buds are formed in late summer and early fall so pruning
then or later is not advisable since it will remove flower buds. New
leaf buds will form in the spring, but new flower buds won't form until
the next year.
VARIETY. Some plants will never bloom. Some rhododendron that come from
the seed of a hybrid plant will look good but will never produce flowers
or will produce very poor flowers. To come true to the parent plant, a
hybrid may be propagated by cuttings or tissue culture but not from
seed. A good hybrid seedling only comes about once in a while. For that
reason it is important to know that you are getting a good named
variety or a good species.
FERTILIZING. Nitrogen promotes leaf and branch growth and discourages
flower bud production. It can also force late season growth that gets
killed or stunted by frost damage. Phosphorus promotes flower bud
production and hardiness. Potassium is necessary for well being.
WEATHER. Cold weather can kill flower buds. Usually you see the brown
buds in the spring. Cold spells in the fall or spring can damage buds
that are not hardened off. Bud blast (blooming in fall or winter) uses
up good buds which are then not available at the normal blooming time.
AGE. Most rhododendron take 2 to 3 years to bloom from a rooted cutting
unless forced. Some take longer and some bloom sooner. From seeds the
plant may take 1 or 2 additional years.
EXPOSURE. Some rhododendron need full sun to bloom and others can take
fairly dense shade. In general, the more sun the more flower buds but
also the greater exposure to damage from desiccation in summer or
winter. More shade produces more foliage and less flowers.
You can usually tell if the plant has ever bloomed. A rhododendron that
has bloomed will have the seed pods on it unless it has been
dead-headed. If dead-headed too late after blooming, new flower buds can
be damaged. There are many other cultural variables that influence the
plant's health and hence, its ability to produce flowers.
Failure of flower buds to open could be due to a number of reasons. On a
mature plant if they ever bloomed they will have a few of the seed pods
still here and there. If you can't find any old seed pods, then they may
have never bloomed. In any case, here are a few suggestions that may
help:
BUD SET. The buds could be foliage buds rather than flower buds. In this
case check the previous section about flower buds not setting.
BUD BLAST. Plants which are not sufficiently hardened off or are exposed
to unseasonal warm spells can start bloom prematurely. These blooms are
seldom satisfactory and many times get frozen before opening fully. In
any case, the seasonal bloom is lost. Also, disease may attack the buds
before they open.
LOW TEMPERATURES. The buds could be flower buds that froze during the
winter. Cold climates are too cold for many rhododendrons. Most
rhododendrons have a low temperature at which the flower buds are
damaged and will not produce flowers. It varies greatly from variety to
variety.
NUTRIENTS. Improper nutrients my be a problem that affects cold
hardiness and flower bud set. A few things you can do are to fertilize
with phosphorus (super-phosphate) per directions to increase hardiness
and flower bud set. This can be done any time. Do not use nitrogen rich
fertilizers as they may inhibit flower bud production and also reduce
cold hardiness. Lawn fertilizers are notoriously high in nitrogen and
should be kept away from flowering plants.
ACIDITY. Measure the pH and acidify if necessary. Flowers of sulfur
(powdered sulfur) is the best chemical to use to increase the acidity
[lower the pH]. Do not use aluminum sulfate since aluminum salts build
up in the soil and eventually becomes toxic to many plants including
rhododendron and azaleas.
PROTECTION. If the plants are wrapped in burlap during the winter, they
may gain a few more degrees in hardiness.
DROUGHT. When soil moisture is too low, the buds will not open. Watering
will usually resolve this condition if detected soon enough.
Good luck,
--
Pardon my spam deterrent; send email to shen...@fast.net
Visit my Rhododendron and Azalea web pages at:
http://www.users.fast.net/~shenning/rhody.html
Also visit the Rhododendron and Azalea Bookstore at:
http://members.aol.com/rhodyman/rhodybooks.html
Cheers, Steve Henning in Reading, PA USA http://www.users.fast.net/~shenning
kjkrout
kjkrout
plant for all I know). Once pruned, it filled out nice and thick. I think the
buds are foliage buds. I do get some kind of leaf brown spots. I wonder if
there is a picture of diseases on Rhodes. What name brand fertilizer would you
recommend? I think maybe I over fertilized them the first two years or so. This
year I decided to leave them alone and let mother nature care for them. I
mulched the area, and I'm wondering if that was a no no because they did bloom
prior to mulching, fertilizing, and pruning. The other older Rhodes in the back
yard are doing fine (and shaded by many large trees), although they got a prune
job but just didn't send any new shoots. I know it's not a weather problem, so
it must be fertilizer, mulch, disease is questionable since they did still bloom
when diseased prior to pruning, mulching and fertilizing. I need to upload
pictures!! I have soil testers now, but what PH would I be looking for? All the
web sites are down right now. Oh well. Thanks so much for all the links and
info! Robin
Sometimes you can kill a plant with too much TLC! I left some aloe plants alone
(yep, in my garden!) that were half dead, and mother nature brought them back to
life! They are experimental plants anyway. My aunt in California tells me that
desserts get very cold, and since we often have drought problems, that the aloe
just may survive our weather!
TOM KAN PA
tom kan pa
Marley1372
usually about 5.5