Japanese maple problems: Experts share to avoid to prevent your acer tree from dying

Japanese maples are a coveted small tree, especially the easily recognizable ones with red, weeping, lacy leaves. That beauty comes with a price, though. Japanese maples aren’t the easiest tree to grow and keep alive. More have died than usual in the past few years, according to experts, leaving gardeners puzzled about what’s going wrong. Gardening experts have weighed in on what are some of the most common causes for these plants to die.

Mike McGroarty, gardening expert at Mike’s Backyard Nursery shared fertilizer is bad for Japanese maples. He said: “Garden fertilizers are a significant issue as they will kill Japanese maples and other plants.

“It’s true. The typical garden fertilizer that you buy for your veggie garden will take out ornamental plants like nobody’s business.

“If you plan to use regular garden fertilizer on your Japanese maple you might as well write ‘serial killer’ on the bag.”

This is because garden fertilizers are designed to be released immediately. The expert continued: “A bag of 14-14-14 garden fertilizer contains 14 percent nitrogen, 14 percent phosphorus and 14 percent potassium.

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“Too much fertilizer is also a cause of leaf scorch with brown or yellowing leaves and excess growth with soft stems that can droop.”

Even if gardeners haven’t applied fertilizer to their maple, it is possible excess lawn fertilizer can dilute in rain water and run to the soil around the tree causing the leaves to scorch.

Mark warned: “It should be noted that due to cold weather, additional fertilizer can be a significant problem if it is applied too late in the season or too early as it causes the new growth to be more vulnerable to frost damage.

“The tender new growth turns black when damaged by frost and can be cut back with a pair of pruners without any significant damage to the tree.

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“Once there has been too much fertilizer applied then there is not much you can do other than give it time to recover.”

The expert advised the only time fertilizer is necessary when growing Japanese maples is if they are planted in a pot or sandy soil. But if this is the case gardeners should only use half strength multi-purpose fertiliser.

The expert added: “Personally I prefer to use Miracle Gro fertilizer as it is in granule form, contains all the nutrients at the right concentration for your plants and it releases nutrients slowly to prevent problems associated with too much fertiliser.

“In most gardens however the use of a compost or leaf mold mulch adds nutrients to the soil, improves the soil structure and conserves moisture providing the optimal conditions of your Japanese maple.”

Mike agreed organic matter should always be used over regular fertiliser. He said: “What a Japanese maple really needs is good rich soil that contains a significant amount of organic matter. Really good topsoil is just that, organic matter.

“That’s what made it topsoil. For years and years vegetation falls to the earth and rots and becomes topsoil. That’s what all plants, especially Japanese maples, need.”

But not all gardeners have good soil, so what can they do? The expert suggested using fertilizer with something organic like fish emulsion fertilizer, Millorganite, or another organic fertilizer.

Mike added: “Keep in mind, Millorganite is good for your ornamental plants but not your vegetable garden because it’s made from sewage sludge.

“When installing new plants, especially Japanese maples, mix some rotted (bagged) cow manure with the soil as you fill around the plants.”