You likely snapped the branches wiring it.
I've used copper and aluminum wire on azaleas for years with no ill effects. Stating aluminum is toxic because aluminum sulfate has shown signs of plant stress over time in one old study is like calling table salt toxic because it contains sodium and chlorine.
I understand the aluminum
wire won't hurt, but aluminum can be toxic to azaleas.. So can copper in large amounts. Again- will the wire leach out enough to hurt them- obviously not, because I think most of us here have wired them with both and had no ill effects. (I even started using Al wire again after the last time we talked about this and have had no ill effects, so thanks for giving me the courage to do it again because I don't generally keep copper wire on hand much..)
But many sources confirm that aluminum can kill them- one of the most clear and to the point:
"To lower the pH (increase the soil acidity), sprinkle several handfuls of ferrous sulphate around the base of the plant. Never use aluminum sulphate, as the
aluminum is toxic to azaleas."
http://www.azaleas.org/index.pl/azculture.html
This one goes into it a little further:
"Never use aluminum sulfate for making the planting medium more acid. Thousands of azaleas and rhododendrons are killed each year by the addition of aluminum sulfate to planting mediums.
Aluminum ions under very acid conditions are very toxic to all of the rhododendron genus.
Aluminum is not considered to be an essential element for plant growth. In fact, for most plants, high levels of available soil aluminum are toxic causing stunting of root growth and
eventual death if soil aluminum is high enough. Usually the soil pH has to be less than 4.5 for this to happen. Rhododendrons and azaleas are more vulnerable than many other plants."
http://www.rhodyman.net/rhodyho.html
Not arguing with you Brian, I just want to make it clear so nobody goes out and tries to make their soil more acidic for their azaleas with Aluminum Sulphate. I was one of the lucky ones who was recommended to use Al Sulphate for Azaleas early on.. And it ended badly.
I think what happens with these concerns about certain things being toxic is similar to what Oso described above- Basically "I used ____ wire/ fert/ soil on my plant and it died/ branches died/ it declined in health, so ____ must have killed it!" When in actuality, the plant died because of... SOMETHING else.. A cracked branch as you mentioned Brian, or a bug/ disease/ too little water on a hot day...
In this instance I tend to believe the cracked branch theory. They are tough to wire, not very pliable once the branches get any kind of girth, it is easy to knock off new growth by accident, the wire bites in and scars them up fast, they crack easily and have thin bark that does not knit up wounds like that well. They are fast growers sometimes, but that doesn't mean they heal over large wounds quickly either.. Again due to the thin bark I guess? Regardless, I have only had success wiring young branches... Older ones I just use wires to pull them down or find an alternative means of bending...
