Plants

Japanese maple

Acer japonicum ‘Aconitifolium’

The Japanese maple enthralls us from October with its bright red fall color; it is an ornamental tree with a particularly picturesque growth. Things to know about planting and care.

Growth type
  • small tree
  • large shrub
Growth height (from)
from 300.00cm to 500.00cm
Growth width (from)
from 300.00cm to 600.00cm
Growth characteristics
  • sweeping
  • upright
  • loosely
  • multi-trunked
Flower color
  • red
Flowering time (month)
  • April to May
Flower shape
  • Cluster
Flower characteristics
  • unfilled
  • hermaphroditic
page format
  • fiddly
  • lobbed
Sheet properties
  • Autumn coloring
Fruit color
  • brown
  • red
Fruit shape
  • nut fruit
Light
  • sunny to semi-shade
Soil type
  • sandy to loamy
Soil Moisture
  • fresh to moderately humid
ph value
  • neutral to weakly acidic
Lime compatibility
  • sensitive to lime
Nutrient requirements
  • moderately nutritious
Humus
  • rich in humus
Decorative or utility value
  • Flower Decoration
  • Fruit ornaments
  • Leaf ornaments
  • picturesque growth
Toxicity
  • non-toxic
Winter Hardness
  • hardy
Climate zones according to USDA
  • 5
Use
  • Single position
  • Planters
  • Lawn areas
Garden style
  • Roof Garden
  • patio
  • Japanese Garden
  • Park area
  • Rhododendron garden
  • Pot garden

Origin

The wild variety of the Japanese maple (Acer japonicum) comes from the mountain forests of Japan. There it grows at an altitude of 656.16 to 4265.09 feet on slightly acidic soils in the open forest. The wild variety can be rarely found in the market. The “Aconitifolium” variety, the Japanese maple with palmate-shaped leaves, is the most common here. Because of its golden yellow, bright red or dark red fall color, it is sometimes also called the Japanese flame maple, although the Flame maple (Acer ginnala) is actually a different species. The Flame maple (Acer palmatum) and its varieties are often mistakenly sold as Japanese maple, which is its German name.

Growth

The Japanese maple is primarily known for its picturesque growth, a short trunk or multi-stemmed growth and for its upright main branches in young trees. Older the tree, more expansive is its foliage. A mature tree of this species can reach heights of up to 16.4 feet. The palmate-leaved Japanese maple is wide compared to its height, which highlights the beautiful, umbrella-shaped crown.

Leaves

The shapely leaves of the palmate-leaved Japanese maple resemble monkshood, but with a length of 5.51 inches they are significantly larger and pinnately lobed almost to the base of the leaf. As with all maples, the deciduous leaves are arranged opposite each other and turn bright orange to wine-red in fall.

The foliage of the palmate leaved Japanese maple in summer

The foliage of the palmate leaved Japanese maple in summer

Flowers

The small blossoms of the Japanese maple open in late April or early May. They have reddish to purple-colored petals and are found in short clusters in the leaf axils. The stamens are strikingly yellow in color.

Fruit

From a botanical point of view, the fruits are so-called nuts and have distinctive fruit wings, typically found in all maple varieties and are also colloquially known as propellers. They are shiny red in summer and dry up in fall. Thereafter, break open and sail down from the tree. The propellers ensure that the seeds do not fall to the ground directly under the tree, but have an inclined flight path. Depending on the wind conditions, they often land a few meters away from the mother plant, where they have a greater chance of survival.

Location

The Japanese maple is the most comfortable in sunny locations. Therefore, you should plant it south-facing as far as possible. If the plants are still young and have not grown in well, the leaves can get sunburned. That is not a problem, because the tree becomes less and less susceptible to it over the years. Partial shade is not a problem for the Japanese maple. However, it does not form a shapely crown at these locations as it grows.

Soil

The Japanese maple grows best in moist, well drained sandy humus soils. It prefers slightly acidic soils and is very sensitive to lime.

Planting

Loosen the soil up to an inch deep before planting a Japanese maple. If the soil is too loamy, you should enrich it: You can achieve a loose soil structure by mixing in sand and leaf compost. A mulch layer of foliage or bark humus ensures that the moisture remains in the soil. The Japanese maple can also be planted in a large container. Choose a flat and wide container with a volume of at least 20 liters.

Care

In drought periods, the shallow rooters needs to be watered regularly, especially if the location is in full sun. In cold winters, the bark of younger shrubs cracks quickly when exposed to strong sunlight. As a preventive measure, the trunks and main branches of younger plants should be wrapped with strips of jute or covered with cane mats.

Pruning

The Japanese maple does not need regular pruning. It naturally forms a beautiful crown and barely looks old, even at a mature age. Most importantly, do not cut back into the old wood, as this will permanently distort the crown. Remove unruly branches completely in late summer. Pruning to correct the crown are only recommended for very young plants.

Winter protection

The Japanese maple tolerates cold winters very well, but is somewhat susceptible to late frosts, as it sprouts quite early. The crowns of younger plants can be protected for a short time with winter fleece if there is still a risk of late frost after they have sprouted.

Where to plant

The Japanese maple does particularly well as a stand-alone plant. Planted in groups, its picturesque growth does not stand out. However, it can be used for making a wooded border more interesting. To do this, plant it in the front row and slightly offset from the other trees. The palmate-leaved Japanese maple can be planted in the garden, in large tubs, and even in courtyards and parks. Its bright red fall colors appear even more intense against evergreen foliage. Japanese maples with bulb flowers look very beautiful in spring.

Varieties

In addition to the broad palmate-leaved Japanese maple (Acer japonicum “Aconitifolim”), there are two other recommended varieties, which also exhibit a picturesque growth and an intense fall color:

Japanese maple “Aconitifolium” (left) with fruits and fall colors, Japanese maple “Vitifolium” (right) with flowers

The Acer japonicum “Indian Summer” takes on a golden yellow color in fall. Its growth is slow and is less expansive than the palmate-leaved Japanese maple. It has multi-lobed leaves.

The Japanese maple “Vitifolium” has a strong dark red fall color. Its exceptionally large leaves resemble grape leaves in terms of shape. This variety grows very quickly and reaches a maximum height of 6.56 feet.

Propagation

Since all garden variety of the Japanese maple produce fertile seeds, the best way to propagate the plants in the hobby garden is by sowing. However, one has to live with the fact that the offspring are not “true-to-type” and partially resemble the wild species. It is best to harvest the ripe seeds in late summer to early fall (September to October), remove the dry wings and sow the seeds shallow in boxes with potting soil. These are then stored in a shaded place outdoors, covered with a cane mat and kept uniformly moist. The cool winter temperatures and frequent temperature changes result in a natural stratification with which the germination inhibition of the seeds is overcome. They usually sprout at the end of February / beginning of March and should then be moved to an unheated greenhouse, where they are protected from late frosts. After the first year of cultivation, the potted seedlings are overwintered frost-free and can then be planted out in the garden in the next spring.

The true-to-type propagation of garden forms is usually only possible with the Japanese maple through grafting. This is done either in spring by splice grafting or in late summer by approach grafting or cleft grafting on potted bases. The grafted Japanese maples are then further cultivated in the greenhouse. The grafting method is quite complex and the growth rates are often not very high - so it should be left to the professionals.

Diseases and Pests

If the Japanese maple adapts well to its location, it will only rarely become ill or attacked by pests. For example, brown or dry leaves suggest a location that is too windy or too humid. As with several maple species, Verticillium wilt is also a serious disease of the Japanese maple. If the tree is infected, the leaves that were recently green and sappy will become pale and wither quickly, the bark or branches will crack and shoots will seem to break off for no reason. If your Japanese maple is infected with this fungus, you must cut off all infected branches, seal the interfaces thoroughly with tree wax and move the tree in a new container or another location in the garden. It is important that you use fresh soil and discard the previous one as thoroughly as possible. The cuttings are also infested and must not be put on the compost under any circumstances. All garden tools used must be cleaned and disinfected, otherwise recurrence of infestation cannot be ruled out.

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