Dwarf Hinoki Bonsai Care Guide
Chamaecyparis obtusa is an evergreen conifer native to Taiwan and southern Japan. In its natural habitat the tree can grow to over 75 feet tall, but as a bonsai reaches a perfect height range of 12-24".
Known as a "false cypress", there are other cultivars of this species however this particular variety is hardier than the others, making a better choice for bonsai.
Hinoki is also known as "fire tree" due to its past and present use in fire-starting rituals in Shinto shrines.
With brownish red bark that peels in strips, this bonsai ages attractively. The foliage is made up of flat, dark green fanning fronds that are almost fern-like in appearance and turn to a reddish color during the winter.
Even though the Hinoki is very hardy and can tolerate temperatures to -10 degrees F, the foliage is vulnerable to dieback from drying winds, so some protection is needed especially in freezing weather. This tree should be grown outdoors in full sun. Some experts say it can be kept indoors during winter, but it must have ample light and be placed away from direct heat sources. If sufficient sunlight is not provided, the interior and lower foliage may brown and die.
C. obtusa is known for being somewhat finicky with regards to moisture levels. It is a thirsty plant, particularly during the growth phase, and cannot be permitted to completely dry out. However, it is vulnerable to root rot if over-watered, which could kill it. The foliage is sensitive to the combination of wind and low humidity and could experience dieback if not kept moist enough. Use a fast-draining soil mixture and water during the morning or early afternoon to prevent the tree from sitting in water overnight. Allow the soil to dry a bit between waterings, but mist regularly and/or use a humidity tray to protect the foliage from drying out too much.
Hinoki False Cypress should be fertilized bi-weekly from early spring through fall. The tree does not like lime, so use an acidic mix. If your bonsai is a blue cultivar, you may add one teaspoon Epsom salts in a gallon of water from time to time; this will intensify the foliage's blue color.
Popular Styles: formal or informal upright, literati, slanted, windswept.
This species can be a challenge due to its need for constant foliage maintenance. If not pruned frequently the lower and interior branches tend to die and not grow back. In addition, new growth only happens on green wood. Pinching of foliage is the best way to shape this bonsai. Do not clip as the ends will turn brown.
C. obtusa may be wired but the branches can take some time to assume their new direction and so may require rewiring multiple times in order to prevent the wires from cutting into the bark. Wiring can be done any of time of year, but it's best to wait a few months after repotting before wiring as wiring can drain the plant of its vigor.
Hinoki may be propagated by softwood cuttings taken in late summer. These cuttings tend to root easily in almost any medium. Seed germination can be tricky, they need a cold pre-treatment and may take a year to sprout. Grafting may be used on this species in the summertime.
False Cypress should be repotted every three or four years for young trees and every three to five years as the tree ages. In hotter climates a richer soil blend should be used for moisture retention. The root ball on this tree tends to grow quickly, necessitating significant root pruning (up to a third or half) – each tree is a little different so you will want to customize your repotting and pruning schedule to meet your bonsai's needs. The pot should be large enough to allow for root growth but not so big that it will hold too much water, putting the tree at risk of root rot.
Insects/Pests & Diseases:
As with most bonsai, proper watering and sun exposure will prevent many problems. The False Cypress can be vulnerable to scale and mites. Scale can be removed with a knife, taking care not to damage the tree's bark. Alternatively you can paint each bug with rubbing alcohol to kill them. Loss of color on the tree can indicate spruce or spider mites – an insecticide may be required in this case.
Tip blight can also affect this species, particularly young plants. This condition causes sooty pustules to appear on the bark, cones, and foliage. A fungicide may be used to prevent or control the disease, and affected foliage should be removed completely. Scorch may mimic the appearance of a disease but is caused by excessive hot, dry sun, stress from freezing temperatures, or not enough moisture.