Admired by all for their elegant habit and their flamboyant colors, Japanese maples require very specific growing conditions. From substrate to watering, from the best planting period to the ideal exposure, you will know everything about these fascinating trees!
How to properly water a Japanese maple?
An Acer should be watered very often but moderately. The humidity level of the air determines the frequency of watering. If it is planted in the undergrowth or under the cover of large trees among dense vegetation, it will better withstand heat episodes thanks to the evapo-transpiration of other plants. The watering will be less sustained in this case, but it is important to keep in mind that this tree feeds itself first of all by its superficial roots. The soil must be kept fresh at this level by regular watering and mulching.
Be careful not to over-water as soggy soil can cause root disease.
How to water a newly planted Japanese maple?
A very abundant watering is done at planting to eliminate any air pockets around the roots. If it rains and the soil is wet on the surface, avoid watering for 15 days because the new roots form better if the soil is not soaked. After that, one watering per week is sufficient until May, when temperatures rise and growth really starts. The frequency of watering increases to every 5 days.
In winter, let nature take its course, except in regions where it does not rain. Watering once a week or even every 10 days will be sufficient.
How to prune a Japanese maple?
It all depends on the species and variety! Some maples do not need pruning, such as true dwarf varieties like 'Hupps Dwarf' or ground cover varieties. The green and red Acer dissectum cultivars have a drooping habit, which widens and then forms real waterfalls; their juvenile branches cover the older ones. For all these varieties, a simple pruning at the end of winter will be necessary to remove the dead wood.
For the other species and varieties of Japanese maples, pruning must be done in a very clean way on branches of 3 to 5 cm in diameter maximum so that the wounds can close as soon as possible.
close as quickly as possible.
On a typical young Acer palmatum, training pruning consists in increasing the number of low branches. Growth will be slowed down but the roots will develop better. In late February, prune to 3 or 4 pairs of buds. The last pair should face the outside of the tree. In subsequent years, prune the previous year's growth to 3 buds still facing outward.
For other species and cultivars, it is necessary to observe the size of the buds and their distribution on the branches. If these buds are smaller and smaller as they rise, the training pruning can be short. On the contrary, if the terminal bud is the biggest, it will be necessary to avoid short pruning.
Once the tree is formed, a transparent pruning is sufficient; it consists in thinning out all the branches to favor the penetration of light and wind while taking care to preserve a beautiful silhouette of the tree and to respect its port.
Growing conditions of the Japanese maple
To properly grow a Japanese maple, it is necessary to get as close as possible to the growing conditions of its natural environment. These maples grow in the undergrowth bathed by a humid climate in summer and less frequent rains in winter.
In these regions, the porous volcanic soil with a neutral or acidic tendency suits them perfectly. The cover of the undergrowth provides them with a subdued light, they are never exposed for long hours to the burning sun but benefit from a few rays of light at the right time of the day. An exposure sheltered from the wind, to the North-West or North-East to receive only a few sunrays in the morning or evening seems ideal.
The Japanese maple fears above all the heat wave and the drought, a balanced watering and frequent misting in case of very dry air will always be beneficial. However, the soil must not retain excess water or be impermeable, compact and asphyxiating. A well drained, fertile, fresh soil with a neutral to acid pH is necessary for its culture.
Is it necessary to prune the shoots on grafted Japanese maples?
If a branch comes out under the grafting point on a Japanese maple, it is necessary to remove it flush with the trunk because the rootstock could then become stronger than the graft and you would lose the characteristics of the tree you have chosen.
Can I water a Japanese maple with tap water?
If the pH of your water is neutral or acid, tap water can be used. If the water is hard, you should store rainwater in water harvesters or tanks to water your maples. If you have a shortage of rainwater, it is possible to compensate by using "pH -" (available in swimming pool stores and sometimes even in supermarkets). These tablets are added to tap water to lower its pH if it is basic.
Can I grow a Japanese maple in a pot?
It is possible to grow the Japanese maple in a pot, for example, if the soil at home is chalky or if you want to decorate your terrace. A plastic pot is preferable because the roots of the maple tend to stick to the walls of clay pots. Knowing that frequent repotting is necessary, it will be easier.
- Choose a pot with a diameter 10 cm larger than the original one.
- Place a layer of pozzolan or clay balls at the bottom of the pot to ensure drainage. Plant your maple tree in a rich mixture of one part good potting soil, one part heather soil and one part compost.
- Water once or twice a week without leaving any water in the saucer.
- Scratch a mixture of ground horn and dried blood at the foot in March, taking care not to hurt the superficial roots.
- In winter protect the pot from rain and wind.
Can you make maple syrup with a Japanese maple?
No. The most used species are large maple trees such as Acer saccharum and Acer nigrum which must be more than 30 years old and whose trunk must exceed 30 cm in diameter so that the collection of the sap does not generate too many risks for the health of the tree.
Harvesting takes place from mid-February to mid-March when night temperatures are negative and day temperatures are below 5°C. Do not expect to harvest maple syrup in the Mediterranean area!
Why do the leaves of my Japanese maple seem 'toasted'?
At the beginning of cultivation, it is not rare that this phenomenon appears for various reasons. The main one is an insufficient root system to ensure the cooling of the leaves. With the years, the maple will be less sensitive to climatic variations. Another cause: an exposure to too much sun or too much wind.
If, in addition to frying, the leaves fall, it is necessary to reduce watering without suspending it.
Why doesn't my maple tree develop new leaves in spring?
This is the obvious symptom of a cultivation problem and a problem with the roots. A substrate that is too heavy, retaining excess water, can be responsible for root asphyxia. It will then be necessary to review its planting in a much more draining environment if the plant can still be saved.
It is also possible that your maple tree does not have enough roots to feed all the branches and ensure the formation of buds. Adding mycorrhizae to the soil can help, as can adding compost. Reducing the aerial surface by light pruning will be welcome.
Also watch out for root aphids which can easily weaken a young tree!
What is a Japanese maple?
"Japanese maple" is a generic term for several species of small trees that are very popular in Japanese gardens and landscape art. Among these species: Acer palmatum and Acer japonicum are the most common, they are divided into many cultivars according to the characteristics of their foliage, their size and their port.
When and how to repot a Japanese maple?
About every two years, repot by gradually increasing the volume of the pot, at the end of February/beginning of March, when the buds start to swell.
A pot with a diameter of 10 cm or more will be sufficient. A mixture composed of 1/3 potting soil, 1/3 compost and 1/3 heather soil will be perfect. Don't forget the drainage with pozzolan!
When to harvest the seeds of Japanese maple?
The seeds or 'samaras' are harvested at maturity around October.
When to sow the seeds of Japanese maple?
Seeds can be sown as soon as they are mature after soaking for 24 hours in warm water. Place them in boxes or in small individual pots filled with potting soil and sand; in a sheltered corner of the garden, stratification will occur naturally.
In regions with very mild winters, a two-month stay in the refrigerator may be necessary before sowing to lift the dormancy.
What to do during a heat wave for potted maples?
Water at least two to three times a week in the early morning or evening after sunset and mist every evening long enough for the foliage to benefit.
Mulch the plant to keep the shallow root hairs cool.
What is the name of the maple fruit?
The fruit of the maple tree is a samara. The seed is attached to a supporting surface that looks like a membranous wing. With the action of the wind, the seed is thus moved to a good distance. This membrane also has the property of floating, so it can be carried away by heavy rains.
