Good day everyone! We have seveal trees in containers on our backdeck in East Vancouver. I'm hoping that someone has a suggestion for a really good fertilizer (including where to buy it), perferably time-released. The trees are planted in cedar boxes (modified to be very well drained) in Sunshine mix #4 planting mix. The trees are: -two Portuguese Laurels -a strawberrry arbutus -a rhodo -a tasmanian tree fern -and a windmill palm. We generally plant annuals around the trees in the summer, if that matters. Thanks so much!