Well, I can help with the fertilizer thing.
You mentioned a "real boost".
My advice, boost not!
These are trees not some pumkin for the fair. Slow steady fat growth is way better than long whippy insect smorgasboard growth.
Here's some info on my site.
We are all about trees - fertilizing
Also, I'd suggest that soil conditioning has far better long term effects. Mulch, organic material, worms, right fungi etc makes for a long term happy tree.
