Posted by Brent Wilson on 9/5/2016 to Planting & Growing Tips
Though delicate looking, Japanese Maples are actually very tough and long-lived trees. They are very easy to grow in the ground or pots. Container culture can extend their useful range. They are extremely easy to grow in containers, a practice taken to it's most extreme form in the art of bonsai.
When considering the magnificent beauty and monetary value your Japanese Maple will add to your property, a little good advice will go a long way to get the most out of your tree.
Here's a breakdown of what you need to know regarding planting a Japanese maple tree...
Most any garden soil will grow Japanese Maples but the soil must be well-drained. They prefer a sandy loam soil with a low to medium amount of organic matter.
As with so many other ornamental plants and trees, constantly wet or soggy soil around the roots of Japanese maples can be problematic. So make sure to plant your Japanese Maple in a well-drained site. Heavy clay or other dense soils should be amended with organic matter. More tips for amending soil below in the step-by-step planting instructions.
Test Soil Drainage Before Planting!
Testing soil drainage is easy, and well worth the time and effort to do before planting your Japanese maple. Start by digging a hole 12" wide by 12" deep in the precise location you intend to plant your Japanese Maple. Fill the hole with water and let it drain. Then, after it drains, fill it with water again, but this time clock how long it takes to drain. In well-drained soil, which is what Japanese Maples require, the water level will go down at a rate of about 1 inch an hour. A faster rate, such as in sandy soil, may signal potentially dry site conditions, and top soil, humus or peat moss can be added to help retain moisture. A slower rate of drainage is a caution that you either need to improve drainage or look for a plant species more tolerant of wet conditions
Japanese Maple grow best in a moderately acid to slightly acid soil ranging from 5.5 to 6.5 on the pH scale. Most average garden soils fall between a pH range of 6.0 to 7.0.
Testing Soil pH
Soil pH is a measurement of the alkalinity or acidity of soil and is measured on a scale of 1-14, with 7 as the neutral mark. Any measurement below 7 indicates acid soil conditions, and anything above 7 indicates alkaline. If you're unsure about the pH of your soil, or whether or not it's suitable for growing a Japanese maple, it's a good idea to test the soil pH in the planting area. You can quickly test soil pH with an inexpensive soil pH tester probe. To raise the pH (make more alkaline) you can add pelletized limestone to the soil. To lower the pH (make more acid) you can apply Soil Sulfur, Aluminum Sulfate, or Chelated Iron. Adding organic compost to the soil or using compost as mulch can also help to increase acidity and maintain acid soil conditions.
Learn More: What is Soil pH and How To Adjust It?
Most Japanese Maples will grow in sun or shade. However, in their natural habitat, you would usually find them growing as understory trees in the dappled sunlight of the forest, or on the edges of woodland borders. Ideally, and especially in hot southern climates, most Japanese Maples prefer to be grown in locations that provide some afternoon shade or filtered sunlight. Direct afternoon sunlight does not kill trees, but the newest leaves of some varieties may burn and/or scald in these conditions. That being said, there are many sun-tolerant Japanese Maple varieties that have demonstrated excellent tolerance of full sun exposure in our central Georgia gardens.
Planting Instructions for Japanese Maple
Below are general guidelines for planting a Japanese maple in various types of soil, ranging from clay to sandy and loam soils.
If your soil drains well, start by digging your planting hole at least three times as wide and no deeper than the root ball of your tree. The wider the hole the better. Place native soil removed from planting hole around the perimeter of the hole or in a wheel barrow or on a tarp.
Depending on the type, fertility and porosity of the soil in the planting area you might want to amend the native soil. When planting in heavy clay or other compacted or poor soils, it is beneficial to thoroughly mix in some organic matter, such as bagged top soil or a good planting mix at a 50/50 ratio with the native soil removed from the planting hole. When planting in very sandy, quick-draining soil you might want to consider mixing in some top soil, peat moss and/or compost to help retain moisture. When planting in well-drained but moist soil with average fertility there is no need to add a soil amendment.
To safely remove your Japanese Maple tree from the nursery container it was growing it's best to use a pair of snips to cut the container away. After removing your Japanese Maple from the container, very carefully loosen some feeder roots around the side and bottom surfaces of the root ball.
As mentioned above, roots of Japanese maples do no like constantly soggy or wet soil, what some call "wet feet." Therefore, it's best to plant them in a well-draining location. Too, you never know when a long, rainy period of wet weather will come that keeps even level or slightly sloped ground saturated. Therefore, I almost always recommend planting a Japanese Maple in a raised mound, which allows roots to grow down to the water table rather than stand in it.
Well-Drained Soil: If the soil in the planting area is well-drained at all times (drains 1-inch or so per hour), even during periods of rainy weather, set your tree in the planting hole so that the top edge of the rootball sits slightly above ground level (an inch or so). You may need to add some soil mix to the bottom of the planting hole to achieve proper planting height.
Moderately Drained Soil: If the soil is moderately drained (drains at less than 1-inch per hour) place the tree in the planting hole with 1/4 (or several inches) of the of the root ball above the ground level. You may need to add some soil mix to the bottom of the planting hole to achieve proper planting height.
Quick Draining Soil: If your soil is very quick draining, such as in loose, sandy soil, plant with the top edge of the rootball level with the ground and make sure to add some top soil or peat moss to the native soil removed from the planting hole to help retain moisture.
Poorly Drained Soil: If the soil in the planting area is poorly drained (less than 1/2 inch per hour) or tends to hold water during long, rainy periods, and there's nothing you can do to improve drainage, but you still want to plant a Japanese maple in the spot, we recommend either selecting a different tree species that will tolerate wet soil, or maybe planting in a large raised mound that allows the rootball to be entirely above ground.
Note: Before backfilling the planting hole around the rootball of your Japanese maple, stand back to take a look and make sure it is properly positioned. Rotate if necessary to achieve best position.
After setting your Japanese maple in the planting hole, use your hand to begin back-filling your soil mixture around the root ball, tamping as you go to remove air pockets. When you have filled the hole to the halfway point you can soak the soil. Then continue back-filling to the top edge of the root ball.
Note: If you are planting with the root ball above ground level, taper your soil mixture gradually to the ground level, essentially creating a raised mound, as shown in the planting diagram above. To avoid suffocating your plant, do not put any soil on top of the root ball. Mulch is okay.
Step 6 (Optional)
When planting a Japanese maple in a location that is far from a water source, and in a well-drained site, you can use your remaining soil mixture to build a low (2-3 inch high) water retaining berm (catch basin / doughnut) around the outside perimeter of the planting hole. This basin will help to collect water from rainfall and irrigation, often reducing the need for hand-watering. The berm can be removed after a year or so, when your tree has established itself.
Next, deeply water the planting area, including the root ball, to a depth equal to the height of the root ball.
Apply a 1 to 2" layer of cured, shredded or chipped wood mulch or pine straw around the planting area to conserve moisture and to suppress weed growth. As the mulch decomposes it will add vital nutrients to the soil that your tree will appreciate.
Note: Avoid the use of freshly chipped or shredded wood for mulch until it has cured in a pile for at least 6 months, a year is better. Avoid placing or piling mulch directly against the base of your plant as this could cause the bark to rot.
Stake your newly planted tree if necessary. Shorter trees usually do not require staking.
Staking a Newly Planted Japanese Maple
Single Stake Method
For smaller trees, use one long stake driven firmly into the ground so that it crosses the trunk of the tree at an angle a foot or two above the ground (depending on height of tree). Use a piece of cloth or a section of rubber water hose to tie trunk loosely against the stake. Loop the cloth around the trunk of the tree and then cross the ends over one another before looping and tying it around the stake. Doing so help to keep the tree trunk from rubbing against the stake in windy weather. Avoid using metal wire as a tie as it can cut into the bark of your tree.
Triple Stake Method
For taller trees, you can drive three 18" long stakes at a 45 degree angle into the ground beyond the outside perimeter of the planting hole. Space the stakes evenly around the planting hole. Use wire or nylon string to tie from the stake to the tree. To protect the bark of your tree, make sure to run the string or wire through rubber hosing where it will come into contact with the trunk or branches. More on this just below.
To ensure your string or wires do not slide down the trunk of your tree, when tying your string or wire to the tree, you will need to tie above a branch. Otherwise your wires will slide down the trunk. To prevent damage to the bark of your tree, rubber hosepipe should be used where the wire touches the stem or branches.
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