Coral Bark Maple (Acer palmatum ‘Sango-kaku’)

Snow covers the landscape, the sky above stark, with naked trees gray and bleak. When winter is here and it seems that all the color has been drained from the earth, it can get pretty depressing for a gardener. Just when you think you can’t stand this depressing view any longer, your eyes fall upon a leafless tree whose bark seems to glow in a reddish pink color. You rub your eyes, thinking winter has finally driven you mad and now you’re hallucinating red trees. When you look again, however, the red tree still sticks out brightly from the snowy backdrop. Read on for some coral bark tree information.

I. Appearance and Characteristics 

Coral bark maple trees (Acer palmatum ‘Sango-kaku’) are Japanese maples with four seasons of interest in the landscape. In spring, its seven-lobed, simple, palmate leaves open in a bright, lime green or chartreuse color. As spring turns to summer, these leaves turn a deeper green. In autumn, the foliage turns golden yellow and orange. As the foliage drops in fall, the tree’s bark begins to turn an attractive, reddish pink, which intensifies with the cold weather.

Winter bark color will be deeper the more sun the coral bark maple tree receives. However, in warmer climates, they will also benefit from some dappled afternoon shade. With a mature height of 20 to 25 feet (6-8 m.) and a spread of 15 to 20 feet (5-6 m.), they can make nice ornamental understory trees. In the winter landscape, the red-pink bark of coral bark maple trees can be a beautiful contrast to deep green or blue-green evergreens.

II. How to Grow and Care

Sunlight

Light is one of the areas that are tricky with coral bark maple. If you go into a nursery, the tag says it does well in areas from full sun to partial shade. There is a dilemma here, though, because you need to know a little more information. New leaves on Sango Kakus, especially juveniles, are prone to sun scorch, but planting your tree in full sun will give you the best fall coloration.

There is, fortunately, a solution. While the the tree is young, in the early spring you can set a shade screen over smaller trees until they become mature leaves that can handle the full sun, at which point you can remove the screen. In the fall, you will have all the benefits of a tree planted in the full sun without damaged foliage.

Temperature and Humidity

Being native to Korea and Japan, the coral bark maple does not tolerate extreme heat or humidity very well. It prefers moderate temperatures with warm summers that are not too hot and winters that are not too cold. It is not incredibly frost tolerant but can withstand some early frosts if placed in a sunny location. Sticking with the recommended growing zones of USDA 6b to 8a is the safest way to ensure a happy maple.

Watering

One very attractive feature of the coral bark maple is its drought tolerance. Once the tree matures, this Japanese maple makes an excellent choice for people looking for plants for water-wise gardens or those who live in areas prone to drought. It is important to water your tree to establish a robust root system. You can do this by watering your tree weekly during its growing season at a rate of 10 gallons per inch of trunk diameter measured by a caliper at chest height. Doing this for the first two years will ensure that your tree is nice and healthy.

Soil

Your coral bark maple is very adaptable to various soil conditions, and this should not be one of the areas that give you any issues. It prefers moist, well-drained soil but will tolerate heavy clays, sands, and loams all the same. It does not do well in soils with a high pH, instead favoring soils ranging from slightly acidic to neutral.

Fertilizing

The Coral Bark Maple isn’t a heavy feeder, so there’s no need to provide fertilizer frequently. It will benefit from a slow-release fertilizer applied yearly in early spring.

The added nutrients will boost new growth, helping new leaves emerge from the defoliated tree.

Choose a fertilizer high in nitrogen content as this will encourage the lush growth of foliage, which is one main asset of coral bark maple.

Pruning

Pruning a Coral Bark Maple (Acer palmatum ‘Sango Kaku’) is an art that, when done right, can elevate the tree’s aesthetic appeal and overall health.

Prune during late winter or early spring while the tree is dormant for optimal results. Remove dead or diseased branches first. Next, focus on shaping the tree by removing crossing or inward-growing branches. Maintain a balanced, open canopy.

Use clean, sharp pruning tools to ensure clean cuts and prevent injury to the tree. Prune just above a lateral bud or branch junction, following the tree’s natural growth pattern. Avoid leaving stubs and promote quick healing.

If the Coral Bark Maple tree has outgrown its space, prune conservatively, removing no more than one-third of the foliage to avoid stress. Coral Bark Maples have a delicate appearance. Avoid over-pruning to preserve their health and beauty.

Propagation

Propagating coral bark maple is best done using softwood cuttings. Seeds are not a good option for propagation as they will only cause the tree to develop into the original Japanese maples.

Here’s a simple process to propagate:

• Find semi-softwood cuttings, not completely woody or herbaceous, but somewhere in between.
• Cut the branches above the leaf node and remove the lower leaves.
• Quickly dip the end of the stem into a rooting hormone.
• Poke a hole into the potting mix and plant the cutting.
• Water the newly planted cuttings and place them in a location with partial shade.
• Keep the potting mix moist until the roots develop. You’ll know propagation is successful once you notice new leaves emerge in your coral bark maple cuttings.

Pests and Diseases

Although coral bark Japanese maple is generally pest-free, some pests like aphids, scale, maple worms, leafrollers, and leafhoppers may occasionally visit.

You can deal with these pests by spraying them with pressurized water and applying horticultural oil to the infected area.

Anthracnose and bacterial blight are common diseases in Japanese maples. Trim off the diseased parts so the infection won’t spread to other areas.

In cases of severe infection, spraying fungicide might be needed.

III. Coral Bark Maple Similar Trees

• Acer palmatum dissectum ‘Red Dragon’

Red Dragon is a stunning Japanese maple cultivar popular for its reddish-purple foliage compared to the coral red bark tree. It becomes more beautiful as the foliage turns crimson red during fall. It’s a small tree, reaching only an average height of 8 feet high.

Hence, it forms a mounding form and an incredible accent in your garden.

• Acer shirasawanum ‘Aureum’

This species is another relative of the coral bark maple tree known for its yellow-orange spring foliage. The red leaves become visible as the tree’s fall color as the season changes to fall. Aureum is a dwarf variety, reaching only 10 feet high.

• Acer palmatum ‘Beni-kawa’

Native to Japan, Korea, and China, Beni-kawa is another cultivar of Acer palmatum that can reach about 15 feet in height. Its leaves are also soft green during spring but turn yellow-gold during fall. It’s very slow-growing and will fit a small-spaced landscape.

IV. Uses and Benefits 

Coral Bark Maple is perfect as a specimen plant in cottage gardens, city gardens, or Japanese gardens and containers.