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The Korean boxwood is a well-known boxwood with gardening enthusiasts. This Asian boxwood type is native to China and Taiwan and is renowned for its tolerance to freezing temperatures (source). If you are interested in this special plant, how long do Korean boxwoods take to grow?
Korean boxwoods take between three and twenty-five years to grow, depending on the cultivar. These boxwoods grow slower than other box trees, averaging one inch (25.4 mm) of growth each year and reaching a maximum height increase of five inches (127 mm).
This article will explain more about when Korean boxwoods reach maturity. It will also provide some useful tips for taking care of your Korean boxwood. Let’s get to it!
When Do Korean Boxwoods Reach Maturity?
The boxwood, or Buxus (which means “box tree” in Latin) is a group of evergreens that comes either in large shrubs or small trees. This garden plant originated in the United States and contained an estimated 150 boxwood cultivars and species in the present (source).
It is already well-known and regarded as suitable for the creation of landscapes.
Korean boxwoods reach maturity when they are between three and twenty-five years old. The maturity age depends on the boxwood’s cultivar and the local soil conditions.
Shrubs under the boxwood family vary in shape, size, soil preferences, and the maintenance they require. Knowing the growth rate or the relative increase in plant size is also crucial in understanding your boxwood’s nature and expected development.
Unlike other species under the boxwood family, Buxus Sinica var. insularis or Korean boxwood grows slowly. Cultivars of this boxwood type vary considerably, from 2 to 7 feet (60.96 – 213.36 cm) tall and up to 10 feet (304.8 cm) broad (source).
Below are a few Korean boxwood cultivars and an estimation of when they will reach maturity:
Buxus sinica var. insularis ‘Sunburst’
‘Sunburst’ is a broad and mounded Korean boxwood variety that boasts a two-toned green and gold leaf coloration. It has a slow growth rate of 1.5 inches (38.1 mm) annually and can typically only reach up to six feet (182.88 cm) after 25 years (source).
Buxus sinica var. insularis ‘Justin Brouwers’
‘Justin Brouwers’ is a small, round, compact boxwood that can only grow approximately two inches (50.8 mm) each year. This Korean boxwood variant can reach a maximum height of about two feet (60.96 cm) and takes 15 years to reach maturity.
Buxus sinica var. insularis ‘Nana’
‘Nana’ grows one to two inches (50.8 mm) annually and has a low mound appearance. It takes 15 years to reach 1.5 feet (45.72 cm) tall and three feet (91.44 cm) wide. This cultivar also has significantly better leaf miner resistance than other variants of the Korean Boxwood.
Buxus sinica var. insularis ‘Wintergreen’
The ‘Wintergreen’ boxwood variety has an oval to rounded shape and will grow up to two inches annually. This is something that is relatively fast for a Korean boxwood. This plant will reach roughly four feet (121.92 cm) in height and two to three feet wide when mature.
Buxus sinica var. insularis ‘Green Mountain’
‘Green Mountain’ is a hybrid of Buxus sinica var. insularis and Buxus sempervirens. It grows around three inches (76.2 mm) a year and has an upright oval shape. The plant will be about four feet (121.92 cm) tall and three feet (91.44 cm) broad in 15 years.
It is good to note that this cultivar can survive extreme winter conditions but is highly susceptible to boxwood leafminers.
Buxus sinica var. insularis ‘Green Velvet’
Similar to Green Mountain, ‘Green Velvet’ is also a hybrid of Buxus sinica var. insularis and Buxus sempervirens. Its shape is moderately rounded or mounded, and it grows around three inches (76.2 mm) yearly.
This variety is exceptionally hardy and can withstand a minimum temperature of – 30°F (-1.11°C). However, it is also vulnerable to boxwood leafminers. This plant will be roughly two feet (60.96 cm) tall and 2.5 feet (76.2 cm) wide and will take 15 years to reach maturity.
How To Take Care of Korean Boxwoods
Korean boxwoods may take a bit longer to grow than other boxwoods, but adequately taking care of them can ensure optimal and steady growth.
Here are some things that can guide you in growing this sought-after shrub:
Use Moist, Well-Drained Soil
Korean boxwood thrives in this type of soil. It would be better if the soil is acidic, loamy, damp, sandy, and claylike to prevent the ground from being saturated with water.
Waterlogged soils deprive plants of oxygen, potentially leading to root rot if they remain unsolved. Proper soil management by adding organic matter can improve soil drainage (source). Mixing sand and clay as the plant’s soil is recommended to offer an appropriate balance of drainage and water retention.
If you are not a professional, learning the correct soil management technique may take some time.
However, it’s a good thing that there are easy and handy-to-use tools like Soil pH Meter (link to Amazon) that can help you monitor your soil nutrition with little effort. With a soil tester like this, you can have a reliable measure of your plant’s soil pH, moisture, and sunlight level.
Plant It In an Area With Full Sun to Partial Shade
Korean boxwoods require full sun to partial shade coverage to grow appropriately.
A place where the shrub would receive at least six hours of direct, unfiltered sunshine per day is optimal. Otherwise, an area with at least two hours of natural daylight or shaded for at least 12 hours can be provided as an alternative (source).
See our guide to Shade-Tolerant or Shade-Loving Evergreens.
Remove Dead Branches Regularly
Leaves that have become lodged in crotches should be removed and destroyed annually, at the very least. Doing so inhibits the growth of fungi like Volutella buxi, which causes the boxwood disease canker or stem blight.
Copper-based fungicides, such as Liquid Copper Fungicide (link to Amazon), can aid in the control of the growth of bacteria and fungi that causes such boxwood diseases.
Protect the Evergreen Foliage From Drying Winter Winds
Winter winds and snow can cause cold damage and stem breakage on Korean boxwoods. It is generally agreed upon that covering the bush using a portion of snow fence, burlap, or any other material is okay as long as it allows air circulation around the plant.
Keeping your boxwood watered properly to maintain soil moisture can also help reduce plant injury during this season.
Boxwoods are some of the most famous plant choices in landscapes. They have many subtypes, including the Korean boxwood, which has its own cultivars.
Korean boxwoods have a slow growth rate that also depends on the boxwood variety. Properly taking care of this plant and putting these ornamental shrubs in your gardens would provide beauty and elegance to its landscape.