For several years now, the Japanese maple (Acer palmatum), which is native to the Japanese islands, has also been increasingly found in German gardens. The rather small, shrub-like growing tree impresses with its frugality and its distinctive foliage, which turns a beautiful orange to red in autumn. Red Japanese maple has a particularly strong color, which can, however, be affected by excessive fertilization.
How should you properly fertilize a Japanese maple tree?
Fan maples should be fertilized moderately so as not to affect the autumn color. For planted trees, compost twice a year in April and June is sufficient. Maples grown in pots should be supplied with a complete fertilizer or special maple fertilizer every three to four weeks during the growing season.
Excessive fertilization prevents autumn colors
Basically, the Japanese maple prefers soil rich in humus and nutrients, but should only be fertilized moderately. Unfortunately, too much fertilization means that the wonderful autumn colors either remain unsatisfactory or even fail completely. The same applies if it is not sunny enough in autumn, because: the more sun the Japanese maple can soak up, the more intensely its foliage will be colored.
Prefer organic fertilizers
For this reason, planted Japanese maples in particular should firstly be supplied with little and, secondly, only with selected fertilizers. If the tree is in normal garden soil, it is basically enough to add compost twice a year. Work in the first portion carefully at the beginning of budding in April, followed by the second portion around mid to late June. Be careful, however, because the Japanese maple has its roots very close to the surface of the earth. If necessary, you can fertilize until around the beginning or middle of August, but you should not fertilize later. This would delay the maturation of this year's shoots before winter and also influence the autumn color.
Fertilize Japanese maple regularly in the pot
In contrast to planted specimens, Japanese maples grown in pots should be supplied with a good complete fertilizer every three to four weeks during the growing season. Special maple fertilizer (€9.00 on Amazon), which is available in well-stocked garden stores, is very suitable for this purpose. But the same applies to fertilization here: less is more.
Incorporate compost when planting
Instead, you should incorporate a large portion of mature compost or, for potted plants, compost soil into the substrate or excavation when planting. The soil can be further improved by adding expanded clay or clay granules and/or coarse sand. This procedure is particularly recommended for heavy, poorly permeable soils.
Tip
Especially for potted plants and on hot summer days, fertilization should be applied in liquid form, for example by adding the product to the irrigation water.
