Zelkova , Olmo Giapponese

Class

Dicotyledoneae

Division

Angiospermae

Family

Ulmaceae

Order

Rosales

Genus

Zelkova

Species

serrata

Description

A deciduous perennial plant, known as Japanese Elm and widely appreciated, in different styles, as a bonsai species for its elegant plant architecture enhanced by the particular colour shade of the bark in adult specimens and the foliage that takes on yellow-orange hues during the autumn period.

Variety description

Plant of the ulmaceae family. In the wild, it is a spontaneous tree from the Caucasian regions, with a globular crown and branches extending from the base. It has a grey, fairly smooth bark, which flakes off with age, showing a yellow-orange-coloured underlying bark. The leaf is deciduous, small, elliptical, simple and fits into the branch with a very short petiole. The upper page is deep green, with a slightly wrinkled lamina and small whitish hairs. The underside is paler, with fine hairs along the main vein. It is grown in pots of different sizes, from 10 cm up to 50-60 cm for special specimens. It is more common to find it in 12-25 cm pots.

Curiosities and special features

Zelkova serrata is often referred to by the term Keyaki in the ancient art form of bonsai, a technique for growing miniature trees that originated in China and spread to Japan, with profound meanings that reconcile philosophical and spiritual principles in the search for 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

Species native to a territorial range extending from China to the southern Kuril Islands and eastern Asia.

Leaf

The small deciduous leaves have a simple elliptical lamina and are inserted into the branch with a very short petiole.

Leaf colour

Homogenous in colour, the upper page is deep green, with a slightly wrinkled lamina and small whitish hairs, while the lower page is lighter, with a thin down along the main vein.

Plant height

The height of the plant varies between 0.2 and 1.5 m, depending on the size of the pot and the setting of the specimen.

Lifespan

Deciduous Leaf perennial plant.

Where to plant

Suitable for growing as bonsai in large pots, small pots.

Stem

The woody stem has a grey, fairly smooth bark that flakes off with age, showing a yellow-orange-coloured underlying bark; the variety has no thorns.

Growth

Medium-vigorous Growth plant.

Plant habit

The developed habitus is bushy with globular foliage.

Branching

Medium with branches also starting from the base.

PH

It requires a pH of 5.5 to 6.5 in the growth and cultivation soil.

Sun exposure

Suitable for the following exposures: half shade, full sun exposure, indoors in not very hot areas.

Ideal climate and temperature

The ideal temperature is between 12 and 25 °CThevital temperature is between 0.0 and 40 °C. Sheltering from cold winds is recommended.

Use

Appreciated in the art of bonsai in:

Exterior ornamental field Indoor ornamental field

Hardiness

A species of medium-high rusticity.

Soil

Utilizzare substrato standard per bonsai oppure una miscela con 30% di componente porosa (pomice, granulato vulcanico...), 40% di parte argillosa (akadama) e 30% di terriccio standard a base di torba.

Difficulty

Cultivation of Zelkova serrata is easy, giving it added value. Like all bonsai trees, it should be cared for very regularly.

Growing tips

Here are some useful cultivation tips specific to achieving optimum vegetative development:

Expose the plant to maximum light Avoid direct sunlight during the hottest hours Always keep the substrate moist

Pruning

Prune continuously during the growing season every 2 or 3 new Leafs formed. In winter, when the plant has lost its leaves, carry out pruning.

Propagation

Mainly from cutting.

Repotting

Repotting every 1 to 2 years, in early spring. For larger specimens every 3 to 4 years.

Watering

Water regularly and continuously, avoiding dryness and stagnation. Prefer irrigation by sprinkling over the pot, under the foliage. On very dry days, spray the foliage with demineralised water during the hottest hours, not in direct sunlight.
In winter, with a defoliated plant, water rarely, on warm days and in the central hours.

Fertilising

Carry out manuring with specific organic granular fertiliser, adjusting the formulations between the vegetative period and the resting period. Spread fertiliser granules over the pot on a monthly basis, burying them lightly and removing those that are exhausted.

Edibility for humans

Non-edible.

Tip

If the substrate dries out too much, which should be avoided as much as possible, immerse the pot in water for 4-5 minutes. Allow to drip and after a couple of hours water regularly. On very dry days, spray the foliage with demineralised water during the hottest hours, not in direct sunlight Every month replace the fertiliser granules, removing exhausted ones.