What is your preference of tree fertilizer for deep root feeding? What about shrubs? Some articles say low nitrogren for mature trees, others say they need quite a bit. Curious what everyone else is doing out there. We've used a 3-2-3 or Earthworks Sea3 & Kick combo in the past, but I have also been looking at Roots PHC 27-9-9 and Growth Products 15-8-4 for Spring.