|What do I fertilize my Japanese Maple with? It is in a large wooden box/pot. What var of acer palmatum is it?
|Sounds like 'Sango Kaku', which is a coral bark maple. Since your tree is in a container you'll want to be careful with fertilizer. Too much will burn the roots and affect the health of your tree. I find it safest and easiest to feed containerized plants with a half strength dilution of a water soluable fertilizer such as Miracle Gro or Peter's. You can feed in the spring and then every 4-6 weeks during the growing season, making your last application about mid-October. Mix the fertilizer (half as much as recommended on the label) into a container of water and then water your tree with it in place of plain water. Feeding in this manner will provide a constant source of nutrients during the growing season without the fear of over feeding and damaging the roots of your maple.