Mistake number one is to give the maple large amounts of nitrogen in the first and second years. A small amount of organic slow-release fertilizer in the spring would be much better for your plants. I have had really good success fertilizing in late April with Fox Farm Japanese Maple fertilizer 4-8-5 and Dr. Earth 5-5-5. Fertilizing Japanese maples, how and when should it be done? You have to ask yourself why you have the compulsion to fertilize your Japanese maple.
Japanese maples are garden favorites with their graceful, slender trunks and delicate leaves. To keep your tree happy, you?ll need to site it. Tip 2 Fertilizing your Japanese maple with the proper type of fertilizer should be done either in late winter while the ground is still cold (frozen?), or after the last freeze in spring. I recommend using a slow or controlled release type fertilizer. A general guideline to use for mature Japanese maple trees is 1/10 pound of nitrogen for every 1 inch of tree trunk diameter measured at 4 1/2 feet from the ground.
If you fertilize other plants in the Japanese maple trees’ area at the same time, use the guideline of 1/10 pound of nitrogen per 100 square feet. These trees need special care for healthy growth, including fertilization. Know when to fertilize young and mature Japanese maple trees to help them produce. Get feeding and watering tips for Japanese maples from the experts at Wilson Bros Gardens.