Many gardeners think of treating themselves to a Japanese maple, with the idea of creating a small Japanese space or just to enjoy the fall spectacle offered by the remarkable changing colors of this heather shrub. However, it should be noted that Japanese maple is known to be fragile, especially in the first years of cultivation. Among the diseases that affect it, the most common is undoubtedly that of dry leaves. What is the cause and how can it be remedied?
Several symptoms, one and the same cause!
Japanese maple is probably one of the most delicate shrubs to grow, although it doesn’t require a lot of maintenance. Placed in unsuitable conditions, its leaves begin to dry from their tips before gradually curling up. The entire leaf then turns brown, before falling. The entire foliage can thus fall (which is frequent on trees undergoing a first repotting), then reborn very gradually thereafter.
In other cases, the leaves take on their autumn color prematurely, sometimes even in midsummer!
For others, finally, in particular cultivars with green foliage, like Acer palmatum Dissectum Viridis, undoubtedly one of the most beautiful, the leaves sometimes have a reddish border which forms around the edge of the blade before gradually spread to the rest of the leaf. She ends up necrosing.
For these symptoms, one and the same cause! The growing conditions are unsuitable! In particular, your maple is often too hot!
Move it!
The most common mistake is to expose a freshly planted Japanese maple in a pot to full sun, on the south side of the garden or patio; whereas this shrub, on the other hand, likes cooler atmospheres!
The Acer fears too bright light and stifling heat roasting its foliage. Find a place in the shade, under the cover of a large tree for example, or, at a pinch, in partial shade (maple then benefits from thick shade all afternoon) .
On the soil or substrate side, offer it a mixture of garden soil and heather soil. All Acers – palmatum and japonicum: the two commonly referred to as Japanese maple – appreciate acidic soils but fear chalky soils. The problem is, these substrates dry out faster than average. So remember to water the shrub very regularly throughout the summer, allowing time for the water to moisten the entire root ball.
Finally, also spare him the gusts of wind. In summer, they accentuate the drying out of the leaves, while in winter, the same wind stings to the quick!
Bottom Line: To prevent premature dry leaves from appearing on your Japanese maple, move it to a shady area, sheltered from the wind, and keep its soil moist. If the young tree is in the ground, wait for the return of more favorable weather conditions (in October) to move it.