Can a Dwarf Japanese Maple Live All Year in a Half Barrel in Zone 6?

Beautiful Color From a Container

• Japanese maples are popular landscaping trees that bring aesthetic value to every season. Like many other deciduous trees, they provide a stunning autumn display, with vibrant shades of red, orange and yellow. But Japanese maples also accent the early spring landscape with young leaves that range from yellow to red before they settle into greenish tones during the summer. These sturdy trees are adapted to U.S. Department of Agriculture hardiness zones 4 to 8, and even during winter they provide some interesting color with green or reddish stems grown during the warmer months.

Japanes Maples in Half Barrels

• Japanese maples are widely appreciated for their ability to thrive in containers, even in relatively small containers. You can grow these compact trees in containers as small as 5 gallons, so the approximately 30 gallons provided by a half barrel will ensure that your Japanese maple will not need to be transplanted into a larger container as it grows. The extra quantity of potting soil in a half barrel will help to protect the roots from the cold of winter and the fluctuating temperatures of spring and fall. Nevertheless, the roots will still be more susceptible to cold weather than the roots of a tree planted in the ground, so in USDA zone 6, you may need to move your tree to a sheltered spot during bouts of severely cold weather.

Barrel Prep

• Your half barrel may not come with drainage holes, so you need to drill some holes in the bottom of the barrel to ensure that excessive moisture does not suffocate your tree's roots. Five or six 1-inch-diameter holes should be sufficient. If too much potting soil tends to spill out the holes, you can cover the bottom of the barrel with 1/4-inch hardware cloth. Do not fill the half barrel with ordinary garden soil -- it is very heavy and may not provide adequate nutrition, drainage or aeration. Choose a formulated potting mix that is intended for container plants; an ideal product would contain high-quality compost and perlite in addition to standard materials such as peat.

The Right Cultivar

• Japanese maples in general are well adapted to container culture, but dwarf varieties are more likely to maintain proper growth and health within the confines of a half barrel. These dwarf varieties have mature heights as low as 8 feet, whereas some larger varieties would naturally reach heights of 30 feet if not restricted by limiting rooting area. Two particularly compact varieties are "Crimson Queen" and "Inaba Shidare"; they both have mature heights of 8 to 10 feet and a shrub-like growth habit. A somewhat larger variety is "Bloodgood," which reaches heights of 15 to 20 feet.