Ilex Crenata Bonsai (Japanese Holly Bonsai) – Species Guide

The ilex crenata bonsai (Japanese Holly Bonsai) is native to Japan, Korea, and some parts of Russia. There are around 400 species in the genus, including evergreen and deciduous trees. The Japanese Holly is a rewarding Bonsai project because its dark green leaves, small white flowers, and black berries make for a beautiful addition to any coffee table or rock garden. The ilex crenata is also an excellent subject for Bonsai beginners.

Positioning Your Ilex Crenata Bonsai

It is important to keep your Japanese Holly Bonsai above 5 degrees celcius/41 degrees fahrenheit. During warm months, this bonsai can be kept outdoors in partial shade to full sun. If kept indoors, place on a windowsill that gets partial or full sun and is away from heaters. During cooler months, keep you Japanese Holly in a cool, unheated room that is well-lit in order to create dormant months for your tree.

Watering

Watering a Japanese Holly Bonsai is a daily activity. First, a humidity tray is strongly recommended for these trees. Place the pot in the humidity tray, but don’t allow the pot to touch the tray. Using rocks or small gravel, raise the pot above the water-line of the tray. Keep water topped off at all times to create a more humid environment for the leaves of the tree. A Japanese Holly will appreciate occasional misting. Water your Japanese Holly / Ilex crenata Bonsai when the soil is still damp, but not soggy. Your bonsai will require more watering during the warmer months, and you should check the soil on a daily basis. In addition to watering, use half-strength bonsai or liquid plant food every two weeks.

Pruning

Pruning and wiring is an important aspect of growing any Bonsai. During early to late spring, cut the new shoots on your Japanese Holly except one or two closest to the stem. You can keep new shoots for propagating if so desired. Wiring, which is another training tool for a bonsai, can be challenging, as the branches may be brittle, so only do this during spring and summer growing seasons, being sure you don’t wrap to tightly and cut off the circulation of the tree.

Re-Potting

Plan to re-pot your ilex crenata every-other year. This is most successful during late spring, when buds begin to open. To check if your Japanese Holly is ready for re-potting, gently lift the tree out of the pot to see if the roots are becoming pot bound. If they are, it is time to re-pot. If they look ok, check again in a year. Re-pot into a ceramic Bonsai pot, 1-3″ deep (depending on previous pot), and a few inches wider than previous pot. Most potting soils are too fine, so you should can add potting bark to the soil as this aids in moisture retention.

Propagation

To propagate the Japanese Holly, use seeds or cuttings. From seed, you must use cold pre-treatment, and then plant in early to late spring. Be patient, as it may take up to three years for sprouting to occur. Cuttings are the easiest way to start a new Ilex Crenata bonsai, especially when they are taken from the current years growth. Cut new growth from a Japanese Holly in early to late spring and start in a separate bonsai pot.