Floopy doopy alder

[spandit]

My alder, planted last year, are mostly doing pretty well but as a result, they have large crowns, big leaves on quite small stems.

 

One of them had been blown by the wind so much that the tube had kinked:

 

 

I had to take the tube off but the stem was so bendy the tree couldn't support itself. I've staked it up the best I can but shouldn't it be strong enough to support it's own weight by now?