Hinoki Cypress (Chamaecyparis obtusa)

Hinoki cypress is native to Japan and is a slow-growing ornamental tree. It usually reaches heights of 35 m tall with a trunk up to 1 m in diameter. Due to the large, tight foliage on this tree, it is often used as a hedge or privacy screen.

I. Appearance and Characteristics 

Chamaecyparis obtusa (Japanese cypress, hinoki cypress or hinoki; Japanese: 檜 or 桧, hinoki) is a species of cypress native to central Japan in East Asia, and widely cultivated in the temperate northern hemisphere for its high-quality timber and ornamental qualities, with many cultivars commercially available.

The Hinoki cypress typically reaches heights of 50 to 75 feet (15 to 23 meters) with a spread of 15 to 25 feet (4.5 to 7.6 meters) at maturity. Exceptional specimens can grow even taller, with the maximum known height being around 120 feet (36 meters). The growth rate of this species is relatively slow, averaging less than 12 inches (30 cm) per year. Its roots are fibrous and spread widely, but they are not known to cause significant problems with infrastructure or other plants.

Leaves

The leaves of Chamaecyparis obtusa are small, scale-like, and arranged in opposite pairs. They are typically dark green with a glossy sheen and have a white stomatal band on the underside, which is a key characteristic for identification. Botanically, the leaves are described as imbricate with a gland on the back of the overlapping scales, which can exude a resinous substance.

Flower

The Hinoki cypress is monoecious, meaning it bears both male and female reproductive structures on the same plant. The male cones are small, globular, and yellow, appearing at the tips of the branches. Female cones are slightly larger, green when immature, and mature to a brown color. They are globular and consist of a few scales. The blooming period occurs in the spring, and the cones mature by autumn.

Fruit

The fruit of Chamaecyparis obtusa is a small, woody cone that matures in the fall. The cones are globular, about 8-12 mm in diameter, and consist of several shield-shaped scales that are arranged in opposite pairs.

Stem

The stem of the Hinoki cypress is straight and supports a pyramidal conical crown. The bark is reddish-brown, fibrous, and has a tendency to peel in long, narrow strips.

II. How to Grow and Care

Sunlight

A Hinoki cypress tree does best in an area with full sun for at least six hours daily. Avoid areas with direct afternoon sun in hot climates because the tree can develop sun scorch.

Temperature and Humidity

The Hinoki cypress tree enjoys a humid climate. In the U.S., it’s best suited for 5 through 8, which cover the majority of the middle of the country.

Watering

During the first year after planting, Hinoki cypress requires regular watering, but once established, this plant is relatively drought tolerant and will need to be watered only during prolonged periods of drought. When the soil around the plant feels dry, the plant should be watered. Water during the active growing season (spring, summer, fall) but cut back on watering when winter arrives.

Soil

Hinoki cypress prefers moist, neutral soil to slightly acidic (pH 5.0 to 6.0.). The soil should be porous and well-drained to prevent excess water around the plant. Apply a 2- to 4-inch layer of mulch around the tree’s base to help retain moisture, keep the soil cool, and fend off weeds that could harm the tree.

Fertilizing

Hinoki cypress doesn’t have any particular fertilizing requirements unless the tree shows signs of nutrient deficiency. New plants that haven’t been established yet may benefit from an organic, slow-release fertilizer designed for acid-loving plants and applied once in spring, at the beginning of the growing season.

Planting Instructions

When planting Hinoki cypress, select a site with well-draining soil and sufficient space for the tree to reach its mature size. Dig a hole twice as wide as the root ball and just as deep, placing the tree at the same depth it was in the container or nursery. Backfill with native soil mixed with compost to encourage root growth, and water thoroughly after planting.

Pruning

When the upright branches of a Hinoki cypress tree forks, you can prune it. Cut into new wood rather than the older brown branches. Prune back dead branches and those that seem out of place to keep the tree looking its best. Ideally, prune during the summer months.

Propagation

The best time to propagate Hinoki cypress by cuttings is late summer, fall, or winter or by sowing seeds outdoors in spring. Hinoki cypress trees feature globose seed cones that are 1/3 to 1/2 inch in diameter.

Although most Hinoki cypress trees are cultivars, growing them from seed won’t produce a tree that is true to type. Vegetative propagation from cuttings is the better method.

Hinoki cypress can be easily propagated through cuttings. Here’s how:

• Use a sharp knife to remove a piece of stem about 4 inches long.
• Remove the bottom foliage up to 2 inches from the cut end. Wet the cut end and dip it in the rooting hormone. 
• Plant the cutting in a pot filled with moist, well-draining, rich soil.
• Place a plastic bag over the cutting like a tent, using sticks to keep it in place. Don’t let the plastic have any contact with the cutting. Covering the cutting this way retains moisture. 
• Place the pot in a warm location but away from direct sunlight. Keep the soil evenly moist and water as needed.
• When the cutting sits firmly in the soil and does not move when you gently tug on it, roots have formed. At that point, you can remove the plastic bag and move the pot to a sunny location. Another safe sign is when roots grow out of the pot’s drain holes. Transplant the sapling in your landscape in the spring.

Potting and Repotting 

Dwarf Hinoki cypress varieties can be grown in containers. Select a pot with large drain holes that are large and deep enough to accommodate the tree as it grows. Hinoki cypress does not like to be transplanted, so the fewer times you have to repot it because it has outgrown its pot, the better.

When repotting it to a larger container, gently tip it onto its side and slide out the tree with as much soil as possible. Move it to its new container, filling it with well-draining, rich potting soil.

Overwintering

Protect the trees against hard frost and icy winds, usually when temperatures exceed 20 degrees Fahrenheit, by wrapping them in burlap or enclosing them in a burlap tent. If your Hinoki cypress is potted, it will require winterizing and continued sun exposure. Place it in an unheated greenhouse or sunny enclosed porch for the winter.

Pests and Diseases

Common Pests & Plant Diseases

Hinoki cypress can be affected by juniper scale insects whose feeding causes foliage discoloration. Managing a heavy infestation might require the application of an insecticide. Another potential pest is bagworms; the nests they form can be removed manually.1

Blight is a fungal disease that primarily affects young trees.1 It’s usually best to water in the morning so the leaves dry during the day. Avoid watering from overhead or leaving standing water on the foliage to control blight.

Common Problems with Hinoki Cypress Trees

Hinoki cypress trees are low-maintenance, easy-going plants once they’re established after a few years.

Yellowing or Browning Hinoki Cypress

Hinoki cypress will shed some of its needles each year in late fall as part of its natural life cycle, but before it does, those leaves will turn brown.

Other reasons for a plant turning brown can include too much or too little water or sunlight, poor drainage, root rot, or insufficient nutrients, usually nitrogen. These trees prefer more acidic soil with pH levels of 6.0. If too alkaline, the roots might not be able to absorb iron from the soil, which can cause chlorosis or yellowing of the needles. Check these factors, do a soil test, or wait until the spring to see how the plant rebounds.

III. Types of Hinoki Cypress Trees

There are more than 200 cultivars of Hinoki cypress trees, including dwarf bonsai types that only grow to 12 inches. Popular small cultivars include:

• ‘Butter Ball’: A globose dwarf variety that showcases bright yellow tips on its foliage with darker green inner foliage
• ‘Confucious’: An intermediate-size plant that has yellow-gold foliage with bronze-green tips, maturing to 4 to 5 feet
• ‘Ellie B’.: A miniature variety with dark green foliage in the warm months and bronze tones in the winter
• ‘Gemstone’: Features an irregular upright form and matures slowly; has varied shades of light and dark green foliage
• ‘Gracilis’: Showcases open branches and a pyramidal form; has more of a slender shape than other types of cultivars
• ‘Fernspray Gold’: Grows to about 10 feet and needs ample moisture; features sprays of green and yellow branches
• ‘Just Dandy’: Grows to the size of a large beach ball within a few years and remains wider than it is tall; has tight foliage
• ‘Kosteri’: Grows to 1.5 to 2 feet tall after 10 years; features light olive-green foliage
• ‘Melody’: Features lacy, bright yellow foliage that resists burning in full sun. Requires well-drained soil; narrow when young but fills out as it matures
• ‘Nana’: Dark green and grows to about 6 to 8 inches tall after 10 years; considered an industry standard that grows well throughout the entire year
• ‘Nana Gracilis’: Features tiny, richly textured branches; a dwarf cultivar, it grows 4 to 5 feet tall after 10 years
• ‘Nana Lutea’: The slow-growing golden-yellow counterpart to ‘Nana Gracilis’; prefers a little bit more shade than other cultivars, particularly during harsh summer months
• ‘Reis Dwarf’: A dwarf variety that can be pruned into unusual formations as a bonsai tree
• ‘Sunny Swirl’: Characterized by the cockscombs that sometimes develop at the tips; features mahogany-red bark and yellow, green, and gold foliage
• ‘Tetragona Aurea’: Grows to 6 feet tall after 10 years, but old plants may reach 20 feet tall; features a narrow crown and irregular branches

IV. Uses and Benefits 

• Ornamental uses

It is also a popular ornamental tree in parks and gardens, both in Japan and elsewhere in temperate climates, including western Europe and parts of North America. A large number of cultivars have been selected for garden planting, including dwarf forms, forms with yellow leaves, and forms with congested foliage. It is also often grown as bonsai.

• Timber

It is grown for its high-quality timber in Japan, where it is used as a material for building palaces, temples, shrines, traditional noh theaters, baths, table tennis blades and masu. The wood is lemon-scented, light pinkish-brown, with a rich, straight grain, and is highly rot-resistant. For example, Horyuji Temple and Osaka Castle are built from hinoki wood. The hinoki grown in Kiso, used for building Ise Shrine, are called 御神木 go-shin-boku, or “divine trees”.