Buxus Microphylla [BUK-sus, my-kro-FIL-uh] is a flowering plant in the Buxaceae (Box) family.
It’s a dwarf shrub with evergreen foliage and small white flowers.
You may hear it called by one of its common names including:
- Little leaf box
- Japanese box
- Korean boxwood
The plant is native to Japan, Taiwan, China, and Korea.
Depending on where the plants originated from, they may receive separate classifications.
For example, boxwoods from Taiwan are listed as Buxus microphylla var. tarokoensis.
Korean Boxwood Care
Size and Growth
Buxus microphylla is an evergreen plant typically reaching about 3′ to 4′ feet tall and achieves a spread of 2′ to 4′ feet.
The shrub produces small, bright green leaves measuring just under an inch long.
The oval leaves create a dense canopy over the woody stems.
The thick foliage also makes it suitable for hedging or pruning as a topiary.
Flowering and Fragrance
Korean boxwood has insignificant blooms.
If it blooms, it produces small white flowers with a pleasant fragrance.
The flowers may appear between April and May.
Light and Temperature
Plant or set in partial shade or areas with light shade and several hours of full sun during the early morning or afternoon.
Avoid direct sunlight throughout the entire afternoon as the sunlight may scorch the leaves, especially in cool climates.
The plant is best suited for growth in USDA hardiness zones 6 to 9, covering most of North America except for the Great Plains, where it may get too cold during the winter.
While it can tolerate freezing conditions, it may suffer from branch damage from heavy snow accumulation.
Watering and Feeding
The soil should remain evenly moist throughout the warmer months.
Check the soil frequently and water thoroughly.
Use slow-release plant food at the start of spring and discontinue use at the end of summer.
Soil and Transplanting
Korean boxwood grows best in moist, well-drained soil.
A mixture of sand and clay is commonly used to provide an optimal balance of drainage and water retention.
When planting outdoors, set the root ball just above the soil surface.
This allows the shallow root system to settle without growing too deep.
Transplanting is recommended every few years for potted plants.
Replenishing the soil helps maintain a healthy root system.
Avoid transplanting plants at the start of spring or the end of winter.
Wait until the middle of spring when active growth starts.
Transplant using the same soil recommendations.
Prune the plant to manage its growth.
Thanks to the thick leaves, it is easily shaped into various designs.
Pruning also promotes better air circulation for the plant.
Remove dead or damaged branches each year.
TIP: Never prune before the last threat of frost at the start of spring.
Pruning encourages new growth which may not survive freezing conditions.
How to Propagate Buxus Microphylla
The easiest way to propagate Buxus microphylla is with cuttings.
- Take the cuttings in the middle of summer.
- The cuttings should be at least 4″ inches and contain no insect damage.
- Prepare the soil by combining equal parts sand, peat moss, and vermiculite.
- Use a 6″ inch pot for every three cuttings.
- TIP: Take multiple cuttings as some of the young plants may not take root.
- Remove leaves from the bottom 2″ inches of the cuttings.
- Expose a small portion of the stem by removing a strip of bark near the bottom.
- Dip the cutting in rooting hormone powder and stick in the prepared soil.
- Water thoroughly before placing a plastic bag over each pot.
- Open the bag each day to mist the young plants.
- The plants should take root within a few weeks.
- After the plants take root, transplant to permanent homes using a combination of sand and clay.
Buxus Microphylla Pest or Disease Problems
The biggest problems facing the Korean boxwood include scorching, root rot, and lack of support.
If grown in full sun in open areas and strong winds, the leaves may become scorched and turn a bronze color before falling off.
Root rot is a common issue when grown in poorly drained soil.
If rot develops, transplant the boxwood to a different spot using a sand-clay mixture.
The Korean boxwood also has a shallow root system.
If grown near other plants, the roots may struggle to support the plant.
Some of the main pests include boxwood mites and the boxwood leaf miner.
Treat infested outdoor plants by spraying the foliage with blasts of cold water.
For indoor plants and plants with severe infestations, use a mild insecticide.
Another concern is the toxicity of the plant.
All parts of the plant are poisonous.
Exposure to the skin may cause irritation lasting for a few minutes.
If ingested, the poison can cause nausea, diarrhea, dizziness, and vomiting.
In extreme cases, the poison is fatal.
Due to these concerns, it should never be grown near children and pets.
Suggested Korean Boxwood Uses
The slow-growing Korean boxwood is often used for edging, hedges, or foundations or cultivated as a topiary.