How Tall Does Boxwood Grow

If you’re planning a hedge, a foundation planting, or a classic garden border, you’ve probably asked yourself, ‘how tall does boxwood grow?’ Understanding the maximum height and spread of these versatile shrubs is the first step to choosing the right variety and keeping it looking its best for years to come. The answer isn’t simple, because it depends almost entirely on the specific type you plant.

Boxwoods (Buxus) are slow-growing, evergreen shrubs prized for their dense foliage and ability to withstand heavy pruning. While they are often seen as small, clipped forms, some can become sizable garden specimens if left untrimmed. Knowing their potential size helps you avoid the common mistake of planting a variety that will quickly outgrow its space, saving you from constant pruning or difficult removal later.

This core question has a range of answers. In general, most common boxwood varieties used in landscaping will reach a mature height between 2 and 8 feet, with a similar spread. However, there are dwarf types that stay under 3 feet and a few species that can grow into small trees over 15 feet tall if left unpruned for decades. The spread is equally important, as many boxwoods naturally grow as wide as they are tall, forming a rounded mound.

Factors That Influence Boxwood Size

Several key elements determine how big your boxwood will actually get. It’s not just about the plant’s genetics.

Variety/Cultivar: This is the most critical factor. Always check the plant tag for its expected mature size.
Sunlight: Boxwoods in full sun tend to grow denser but may stay slightly smaller. In deep shade, they often become leggy and can stretch more.
Soil and Nutrients: Rich, well-drained soil with consistent moisture supports healthier, more robust growth. Poor, dry soil stunts them.
Pruning: This is your primary tool for controlling size. Regular shearing keeps them compact, while infrequent pruning allows for natural growth.
Climate: Growth rates vary by region. A boxwood in the warm, long-season South may grow faster than one in a cooler Northern climate.

Maximum Height and Spread of Popular Boxwood Varieties

Here’s a practical guide to the potential size of common boxwoods. Remember, “mature size” often refers to a 15-20 year timeframe due to their slow growth.

Small/Dwarf Varieties (Under 3 feet)

‘Sprinter’ (Buxus microphylla): Fast for a boxwood. Height: 2-4 ft. Spread: 3-4 ft.
‘Green Gem’ (Buxus hybrid): Very hardy, rounded ball. Height: 2-3 ft. Spread: 2-3 ft.
‘Green Velvet’ (Buxus hybrid): Popular rounded form. Height: 3-4 ft. Spread: 3-4 ft.
‘Morris Midget’ (Buxus sinica): Extremely slow, tiny mound. Height: 1-1.5 ft. Spread: 1-1.5 ft.

Medium Varieties (4 to 8 feet)

Common Boxwood (Buxus sempervirens): The classic. Can be kept small but left alone, it reaches 5-8 ft. tall and wide.
‘Green Mountain’ (Buxus hybrid): Conical shape. Height: 4-5 ft. Spread: 2-3 ft.
English Boxwood (Buxus sempervirens ‘Suffruticosa’): Very slow, dense. Height: 3-5 ft. Spread: 3-5 ft.
Japanese Boxwood (Buxus microphylla var. japonica): Heat-tolerant. Height: 4-6 ft. Spread: 4-6 ft.

Large Varieties/Tree Forms (Over 8 feet)

American Boxwood (Buxus sempervirens ‘Arborescens’): Can grow 10-15 ft. tall and 8-10 ft. wide, often used as a small tree.
Buxus sempervirens ‘Dee Runk’: Upright, columnar habit. Height: 8-12 ft. Spread: 2-3 ft.
Buxus sempervirens ‘Fastigiata’: Another tall, narrow option. Height: 8-10 ft. Spread: 2-3 ft.

How to Control and Maintain Your Boxwood’s Size

You are not at the mercy of your boxwood’s genetic potential. With proper technique, you can manage its growth effectively.

Pruning for Shape and Size Control

Prune in late spring or early summer after the first flush of new growth has hardened off slightly. Avoid late summer/fall pruning, as this can encourage tender new growth that may winterkill.

Use the Right Tools: Keep hand shears for detailed work and hedge trimmers for large, flat surfaces. Always ensure blades are sharp.
Thin, Don’t Just Shear: For healthiest plants, occasionally reach inside and prune out entire branches back to a main stem. This improves air circulation and light penetration, reducing disease risk.
Shape Gradually: Never remove more than one-third of the total foliage in a single year. If a plant is severely overgrown, reduce it over two or three seasons.
Maintain a Taper: For hedges, prune so the base is slightly wider than the top. This allows sunlight to reach the lower branches, preventing them from becoming bare.

Planting for Future Growth

Smart planting prevents future headaches. Always space boxwoods based on their mature width, not their size at purchase. For a seamless hedge, space plants about half of their mature spread apart. For example, if a variety spreads 4 feet, plant them 2 feet apart. If you want individual mounds, space them at least as far apart as their mature width.

Troubleshooting Common Size-Related Problems

Leggy, Sparse Growth at the Bottom: Usually caused by too much shade, overcrowding, or only shearing the top. Thin interior branches and ensure the plant gets enough light.
Rapid, Unusual Growth Spurts: Can be a response to over-fertilization, especially with high-nitrogen fertilizers. Stick to a balanced, slow-release fertilizer in spring.
Stunted Growth: Check for poor drainage (wet feet), compacted soil, root rot, or boxwood blight. Poor nutrition can also be a factor.
Winter Dieback: Browning or dead patches can make a plant look misshapen. Prune out dead wood in spring and consider providing winter wind protection for vulnerable varieties.

FAQ: Your Boxwood Size Questions Answered

What is the fastest growing boxwood?

The ‘Sprinter’ boxwood lives up to its name and is consider one of the fastest. Some varieties of Japanese boxwood (Buxus microphylla var. japonica) also grow relatively quickly compared to others.

Can I keep a boxwood small forever?

Yes, absolutely. Through annual pruning, you can maintain a boxwood at a desired size for decades. Choose a dwarf variety if your target size is very small (under 2 feet) to make maintenance easier.

How wide do boxwood shrubs get?

Most common varieties grow as wide as they are tall, forming a natural globe shape. Always plan for the mature spread, which for many types is 3-6 feet. Columnar varieties are the exception, with spreads only 2-3 feet wide.

What happens if I don’t prune my boxwood?

It will grow to its natural mature height and spread, which for some types can mean becoming a large, broad shrub or even a small tree. It may also become less dense inside as foliage concentrates on the outer edges.

How can I make my boxwood grow taller?

To encourage upward growth, limit pruning on the top of the plant while still pruning the sides to maintain health. Ensure it has ideal conditions: well-drained soil, consistent moisture, and appropriate fertilizer. Patience is key, as they are inherently slow growers.

Choosing the right boxwood for your space starts with a clear understanding of its potential. By matching a variety’s natural maximum height and spread to your garden’s needs, you set yourself up for success. With informed planting and mindful pruning, you can enjoy these timeless, elegant shrubs without them ever outgrowing their welcome.