Acero Palmato

Class

Dicotyledons

Division

Angiospermae

Family

Sapindaceae

Order

Sapindales

Genus

Acer

Species

palmatum

Description

Third-size tree, up to 10 metres tall, deciduous polyennial. Appreciated in landscaping and outdoor ornamentals for its developed habit and elegant foliage with intensely coloured leaves that vary depending on the cultivar or variety grown. It adapts to different soil and climate conditions, including those in urban areas. It is also widely cultivated in the art of bonsai as an impressive species due to the colouration of the leaves before the seasonal fall.

Variety description

A plant of the aceraceae family, the palm maple is also called Japanese maple because most cultivars and varieties of Japanese maple originate from it. Native to Japan, it is a complex species and quite variable in leaf shape and colour. It has red, green, variegated leaves. The leaf has 5 to 7 lobes arranged in a palmate fashion, lanceolate, sometimes very sharp and ending in a thin tip; the margins are serrated or doubly serrated. They are upright trees with rounded tops and wide open crowns. They can reach up to 10 - 12 metres. They are very rustic, robust and adapt to a wide variety of climatic and growing conditions. Japanese maples grow in different types of soil and reach altitudes of up to 1,300 metres. There are varieties grafted to form a drooping crown. The use is mainly ornamental for gardens, terraces, parks and planters. Both in soil and in pots of a suitable size for the species and size. It is also widely cultivated as a bonsai, which means, precisely, 'potted plant'.

Curiosities and special features

Acer palmatum plays a primary role in the art of bonsai, the technique of growing miniature trees with very ancient origins. Originating in China and spreading to Japan, it takes on profound meanings that reconcile philosophical and spiritual principles, in search of a symbiosis between man and nature. Today, also thanks to cultural exchanges and international events in the sector, bonsai cultivation has developed throughout the West.

Origin and distribution

A species native to China, Korea and Japan; now present in Europe with a wide assortment of cultivars and varieties that differ in height attained as well as leaf size and colour.

Leaf

The leaves have palmate lamina with a number of lobes varying from 5 to 7, sometimes acuminate and ending in a thin tip; the leaf margin may be serrated or doubly serrated.

Leaf colour

The solid-coloured foliage turns to bright, shiny shades during the autumn period before falling.

Plant height

The height of the plant varies from 0.4 to 1.5 m, depending on the growing conditions and the variety used; in general, the Japanese maple is a third-size tree.

Lifespan

Deciduous perennial plant.

Where to plant

Suitable for growing in large pots, small pots.

Stem

The stem is woody with homogenous, grey or brown bark depending on the variety.

Flower

It flowers for between 10 and 15 days. It is not particularly attractive to pollinating insects.

Growth

Compact growing tree. Crown formation is continuous in the juvenile phase with semi-woody branches, then lignification is stable and maintains the assigned morphology.

Plant habit

The habitus is erect with a rounded top and wide open crown; there are varieties for landscape use grafted to form a drooping crown.

Branching

It develops Medium branching.

PH

Like many other deciduous trees, Japanese maple requires a soil or substrate pH of between 6.0 and 7.0.

Soil preparation

For use as a tree: before transplanting at the end of winter, choose the most suitable location, in relation to the needs of the plant, and use a spade to make the planting hole at least one third the size of the root or root ball volume, removing any weeds and bulky pebbles. It is also advisable to bury organic or chemical fertiliser, and to add organic matter.

Sun exposure

Suitable for exposures in half shade, light shade, full sun.

For cultivation as a bonsai tree, a full sun exposure in spring and autumn is recommended, while in summer it is suitable for medium shade.

Ideal climate and temperature

The ideal temperature is between 5 and 30 °C for proper vegetative growth.

Use

Appreciated for its bearing and elegant foliage as a plant in:

Outdoor ornamental Ornamental Indoor ornamental

Hardiness

A moderately hardy plant. As a bonsai tree it does not tolerate too much high heat and growth must be regulated and 'kept' with great care through proper exposure to light, by shading, as well as appropriate fertilisation, watering and pruning.

Soil

It adapts to different soil conditions, however, the ideal soil for proper vegetative development must be loose, light and well draining.

For cultivation as a bonsai tree, choose a specific bonsai soil with good drainage capacity; if necessary, a mixture of 30% porous component, 45% clay component (akadama) and 25% peat-based soil can be used.

Difficulty

Overall, cultivation is fairly easy, with a medium level of management effort required.

Growing tips

The following are some specific tips and cultivation aspects to achieve better vegetative growth ofAcer palmatum:

Correct pruning Avoid direct sunlight during the hottest hours Keep the substrate dry at low temperatures Requires abundant but no stagnant watering

Planting

For use as a tree: choose healthy specimens, free from abiotic and biotic stress conditions. Always identify the planting site in advance in relation to the growth conditions required by the species according to the principle 'the right plant in the right place'. Transplant the young plant in loam or loose, light soil, not frozen, to encourage root development. It is advisable to place the root ball in the previously dug planting hole, keeping it well compacted around the root and keeping the plant's collar off the soil surface, and then water after planting without causing water stagnation.

Pruning

For use as a tree: do not prune young plants in the first years of transplanting, whether grown in pots or soil. In winter, during the dormant phase, carry out correct training pruning according to the desired size, shape and width of the foliage. Use braces to guide the shape of the plant to support small and weak branches. Indiscriminate cutting of stems and branches by 'pruning' not only leads to an alteration of the natural habitus of the plant, but also to a lower resistance to biotic and abiotic agents as well as to a greater danger of failure of the entire specimen.

For use as bonsai: keep the shoots short, cutting the growth to 1 or 2 leaf buds throughout the growing season, with continuity so that the plant does not lose its shape. In winter reduce the branches by selecting them so as to leave air between them.

Propagation

Propagation is by grafting and cutting.

Repotting

For use as a tree: when grown in pots or planters the soil must be renewed every two years or at least supplemented with new soil and organic fertiliser.

For use as bonsai: repotting should be carried out every 1 to 2 years before full vegetative awakening, in late winter-early spring, and in more mature plants every 2 to 3 years.

Watering

For use as a tree: needs constant but balanced watering, even several times a week if the season is very hot. If possible, place the plant in partly shaded areas as the leaves can become dehydrated by developing fine, thin tips. Also keep the substrate or soil always slightly moist preventing both water stagnation under the foliage and dryness.

For use as bonsai: water above pot and under crown, allowing to dry slightly between two successive waterings. Water abundantly throughout the growing season, reducing from autumn when the temperature drops sharply. With outdoor plants during the winter it is preferable to keep the soil relatively dry in order to reduce the risk of frost damage.

Fertilising

For use as a tree: when transplanting, carry out a basic fertilisation by applying slow-release organic or chemical fertiliser specifically for ornamental plants to the soil. After proper establishment in the new planting site, if grown as a garden plant, fertilise in spring and early summer with a complex, iron-rich fertiliser.

For use as bonsai: fertilise continuously during the vegetation period with slow-release organic fertiliser specifically for bonsai; the plant will then have the necessary nutrients available through subsequent irrigation. Every month remove exhausted fertiliser granules and replace with new ones. In summer reduce the dosage and from late autumn, with the change of season, change the type of fertiliser using a specific fertiliser with a lower nitrogen content.

Edibility for humans

Non-edible.

Tip

Attention to watering, somewhat delicate care. Water abundantly in spring and summer and also in autumn, if hot. Allow the soil to dry just a little between watering, at least superficially. Avoid over-drying, especially if the plant is kept outdoors and particularly if there is wind, even weak wind, which dries out the substrate quickly. It may also be necessary to water several times a day if the plant is placed in a small pot.