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Something is amiss with the shade advice!

Posted by sonny300 z8 B.C. (My Page) on
Mon, May 29, 06 at 23:18

Please take a look at (mp page) and note the flowering azeleas, both decidious and evergreen. I just dont get it--why 90% of my azeleas are flowering this year and only 5% of my Rhodos. Thought that azeleas needed more light than rhodos. This makes it hard to believe that the problem is a lack of light. I have never used hollytone before, but am wondering if maybe I should. Just using a light top-dressing of sterialized steer manure the past couple of years. Also, have been spraying every 15 days with Lagon and now see no evidence of notched leaves on new growth-(I did have a lot of weevils.) Would the weevils have inhibited the flowering? Thanks


Follow-Up Postings:

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RE: Something is amiss with the shade advice!

The correct advice is that some azaleas and some rhododendrons need more light than other azaleas and other rhododendrons. The two rhododendrons you have photos of blooming last year are both late blooming R. maximum hybrids and would be genetically inclined to bloom in more shade than other rhododendrons. If they are not blooming this year, then you have problems.

Steer manure is equivalent to .3-.2-.1 . This is a the wrong ratio for rhododendrons and azaleas. The excess of nitrogen will reduce flowering and increase foliage growth.

HollyTone is much better, it is 4-6-4. I am sure you will use more steer manure than HollyTone, so steer manure is much higher in nitrogen.

Probably cutting back on fertilizing all together and perhaps moving rhododendrons where there is less shade of removing some of the shade may be long term solutions. If we knew what varieties of rhododendrons didn't bloom and how much shade they had, we could look at this more objectively.

Lagon is dimethoate, the same as Cygon. On rhododendrons and azaleas it is labeled for Azalea and Rhododendron Lacebugs, Leafminers, Mites, and Whiteflies, but not weevils. Your photo of Rcv. Midsummer shows lots of weevil damage and other insect problems..

The recommendation for weevils is:

Physical Control: Trap them in burlap placed around plants. Shake out every day over a bucket with soapy water.
Use Tanglefoot or other sticky substances around stems to trap adult Weevils as they climb up into the plants. Make sure branches and leaves do not touch the ground.
In greenhouses apply this to all table legs etc. to trap weevils that are crawling around at night.

Biological Control: Use Nematodes (Steinernema carpocapsae and Heterorhabditis heliothidis). Since Weevils do move through the soil they are very vulnerable to Nematodes. Mix Nematodes with water and apply to the soil. Keep area moist otherwise Nematodes dry out and die.
Ground Beetles are predators to Weevils.

Chemical Control: Spray leaves in the evening at dusk as new damage occurs with Malathion or Methoxychlor. Repeat in 10 days or when more leaf damage is evident.
TO CONTROL LARVAE, use Diazinon as a soil drench around Rhodos etc. Do this early spring when weevils were present last year and again in June when there is more evidence of Weevils and repeat 2 weeks later. Repeat again until November as new damage or adult Weevils are noticed.

Here is a link that might be useful: Rhododendrons for Shade


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Some named Rhodos for Rhodyman

Thanks for your reply:re Something is amiss with the shade advice!
Whats not blooming?-County of York, Senator Jackson,Beauty of Littleworth,Mrs A.T.Delamare,Vulcans Flame,Cosmopolitian,America,Grace Seabrook,Lee`s Dark Purple,Azor,Top Banana,Virginia Richards,Carry Ann,Yaku Prince,President Rossevelt,Gold Flimmer,and a half dozen others. Hope this helps you help me.. Thanks and no Camelias, and no Kalmias, quite a list huh?


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RE: Something is amiss with the shade advice!

None of the plants you mention are for full shade.

America: Partial Shade. Best with full sun.
Azor: Partial Shade
Beauty of Littleworth: Partial Shade. Prefers morning sun.
Cary Ann: Partial Shade
Cosmopolitan: Partial Shade
County of York/Catalode: Partial Shade. Prefers light shade.
Goldflimmer: Partial Shade
Grace Seabrook: Partial Shade
Lee`s Dark Purple: Partial Shade
Mrs A.T.Delamare: Partial Shade. Prefers afternoon shade.
President Roosevelt: Partial Shade. Afternoon protection from full sun is suggested.
Senator Henry M. Jackson: Partial Shade
Top Banana: Partial Shade
Virginia Richards: Partial Shade
Vulcan's Flame: Partial Shade

All rhodododendrons require open to medium shade except for two. They are 'Snowlady' and R. schlippenbachii. They will bloom in deep shade. In northern latitudes, plants will tolerate less shade.

Those that are more shade tolerant are: Bow Bells, Dora Amateis, Elviira, Hotei, King George, Mrs. Henry Schroeder (evergreen azalea), Nova Zembla, 'P.J.M'. hybrids (they don't set seed), Ramapo, R. williamsianum, R. calendulaceum, R. carolinianum, R. kuisianum, R. occidentale, and R. poukhanense.

Other than variety, there are a number of other factors that may lead to a failure to set flower buds:

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.

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 rhododendrons 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 rhododendrons 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.

Inspection. 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.


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RE: Something is amiss with the shade advice!

Thanks again Rhodyman;

Well, at the risk of execution, I am going to cut down a couple of Western red cedars. My wife always threatens me with dire consequences whenever I cut down a tree, so it is a constant battle-(I`m the gardner, and she is not).

I`m going to fall a couple of them on the Southeast side of the property which will allow more light from approx. 7:00am till 1:00pm. They are close to my neighbors property, so will get him to supervise me, he is an old logger, and always very helpful. "and hopefully, the better half wont notice".lol

I have been growing Rhodos for 14 years and I do deadhead, and am always looking for the plump buds in Sept. and have always suspected that more light is the answer, that I know just by walking around the neighborhood. Eg: an Ariculatium that is now 14 years old is only 7ft tall, and it should be about double that. Maybe you could direct an Email that she could read that might help me get my Rhodos going--something like, (okay some trees come down, but your husband has treelike Rhodos that will be much more effective, and yes, you will still have your privacy).
I probably should`nt ask you to do that, your advice has been priceless, and asking you to be a mediator probably isn`t fair. But, "boy-oh-boy" would it be appreciated. take care and thanks again for all your help.You are a great asset to this forum.. george


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