here is a lot to love about Japanese maples. They have fantastic branch structure and come in several forms, like upright and weeping. Many have gorgeous burgundy leaves, and some even sport multi-color leaves. They fit in small spaces where other trees don’t, and they can be drop-dead gorgeous. Don’t let their small size fool you: Japanese maples are pretty tough and deserve a place in our landscapes.
They do have their limits, though. Most are hardy to our Zone 6 weather; however, most are not hardy in Zone 5, just one agricultural zone colder, so it is possible for them to suffer in extreme cold. In 2010, the year of Snowmageddon, Shadowlawn Avenue lost four mature Japanese maples. They simply were frozen by the onslaught of freezing rain that clung to the branches, a foot of snow, and lingering cold temps. It was a difficult loss. I bought several new Japanese maples in the years following, and I checked the tag and online to see what the agricultural hardiness zone was for each.
Japanese maples generally like morning sun and afternoon shade. Although the tags say they can handle full sun, I have found that these understory trees really appreciate some protection from the worst heat of the day. Also take into consideration radiated heat from a street or sidewalk. These trees are unlikely to be healthy street or parking lot trees.
Once established, Japanese maples are low maintenance. Have a trained arborist do the trimming, and for heaven’s sake please don’t trim your weeping Japanese maple with hedge trimmers.
There is a Japanese maple for every site. I am going to talk about six good choices for the Mt. Lebanon landscape or garden. I have experience with such trees and know them well. And of course, they are all hardy to this region.
When choosing your Japanese maple, always keep the background in mind. If your home is red brick you might choose from the green-leafed varieties. Conversely, if your home is yellow brick, as is so common in Pittsburgh, the red-leafed varieties will provide a beautiful contrast.
First up, let’s look at Sango Kaku, otherwise known as coral bark maple. This great tree gives four seasons of interest, and you can’t get much better than that.
Most notable are the bright coral twigs in winter. Spring brings beautiful yellow/chartreuse leaves, rimmed in red, that fade to green. In the fall, this tree blazes with neon orange leaves. The mature height is 25 feet high and 20 feet wide; when you plant, make sure you give your tree enough room. If a tree is going to be 20 feet wide, it needs to be placed about 10 feet from the house. You could plant it closer to the house if it’s in a shady location, and it won’t ever reach 20 feet wide. I love to use this tree next to a porch or near a window where it can be seen up close.
One of the most common Japanese maples in the retail trade is known as Bloodgood. This tree can reach 30-by-30 feet, but is likely smaller at 20-by-20. Bloodgood’s claim to fame is that its leaves hold their burgundy color most of the season, especially if it gets a good shot of morning sun.
Bloodgood is a workhorse in the garden: tough, but very pretty. Pretty companion plants include large golden hostas and Annabelle hydrangeas.
If you want something that stays small, Shishigashira could be a great choice. Shishi is quite diminutive, almost shrublike, topping out at about 15-by-10 feet, but likely smaller. Shishi’s claim to fame is its small, crinkly, intense green leaves that add a lot of texture to a planting. Those attributes are nice, but its fall color is something to behold. This tiny tree packs a wallop by turning multiple neon shades of red, green, orange, yellow, and violet. Shishi can be pricey and scarce. If you see one you like, buy it.
For many years, it was not possible to find a Japanese maple that was taller than wide. Not so anymore. Red Sentinel is that tree. Red Sentinel is a relative of the Bloodgood, but its narrow habit allows us to use it where Bloodgood would simply be too wide—its low branches would cover a front door. Red Sentinel will never overwhelm your front door. Its mature height is 12 feet and width is 8 feet. I have had one in my garden for about 10 years, and it is quite diminutive. Imagine two of these beauties flanking either side of the front door of a white brick, center-entrance colonial. The contrast in summer color is striking, and the winter silhouette of deep burgundy branches would be really nice as well.
Weeping Japanese maples are also an American garden favorite. And why not? The habit or shape of the branches offers an alternative in our shrub beds and landscapes. Be careful where you put these little beauties because they seem to always get too wide or too tall. Believe me when I say they are not easy to move.
Make sure you know the name of the cultivated variety you are considering before you go to the nursery.
I have a beautiful Japanese maple in the back yard that was supposed to be 5-by-5 feet. It is in full shade and shares a bed with a giant white oak tree. What does that tell you? It tells me this Japanese maple is reaching for sun, so it got wider than normal and is probably not getting its fair share of water; the pH is not neutral but acidic for the oak tree and it’s also competing with a ground cover and several hydrangeas. The giant oak is getting everything, so my sweet Japanese maple is nearly twice as wide as I was told, and never reached its 5-foot height.
Although weeping, another maple, Tamukeyama, presents itself in layers. The mature height is about 8 feet, and width is 12. So that means the center of the tree should be at least 6 feet away from the foundation of a house or a sidewalk. Its leaf color is burgundy, and it holds the color very well throughout the season.
Waterfall is a very popular green-leafed weeping variety, cascading with slightly larger leaves. Its bright green leaves have a longer, more flowing appearance resembling a soothing waterfall. Fall color is yellow with a hint of crimson. This outstanding cultivar holds well in full sun and can grow to about 6 feet.
All in all, whatever you choose, your home and garden will benefit from having one or more of these small trees that provide so much beauty and interest.
Once you’ve selected your tree, follow these steps for planting. Dig your hole twice as wide and no deeper than the rootball, and then put the soil aside. Add up to 50 percent compost and mix it in thoroughly. If it is clumpy, break up the clumps with a shovel until it’s smooth. In general, maples are shallow rooted, so keep those roots near the surface. Most likely you will need to do a little excavating to find the main roots. Carefully, without scratching the trunk, scrape off the excess soil covering the roots.
Next, fill the hole with water, and see if the water drains into the surrounding soil within 30 minutes. Japanese maples do not like to sit in standing water; this leads to root rot, which will eventually kill the tree. If your tree is balled and burlapped, set it in the hole with the crown slightly above grade, backfill a quarter of the way, and then cut the burlap off as low as you can get it.
You’ll be leaving only a small amount of burlap underneath the tree. If there is a cage, use bolt cutters to cut it off. Then fill the hole halfway with your backfill, making sure your tree is supported and standing on its own. Once again, fill the hole with water. This time, the goal is to thoroughly hydrate the root ball of the tree. Once you are satisfied the root ball is saturated, fill the rest of the hole, making sure the crown of your tree is not covered by more than half an inch of soil. Once you have filled the hole, water until the soil around the tree is mushy. Water again when the soil is just moist to the touch.
We mulch for a variety of reasons, and the highest priority is plant health. Putting up to three inches of natural double- or triple-shredded hardwood mulch on the root zone is beneficial. Don’t mulch up the trunk of the tree—it is bad for the tree’s health. Mark the turf, and dig it out with a flat shovel, getting just under the surface of the grass. Throw the leftovers in your compost. For newly planted trees the size of a Japanese maple, a 5-foot diameter circle of mulch is fine.
If you want a long-lived tree, keep the roots healthy. The biggest mistakes homeowners make when planting a tree is planting too deep and not watering enough. I can’t tell you how many times I have walked on a property and seen a Japanese maple buried in the ground six or eight inches too deep. The tree may grow pretty well initially, but it will decline—it simply won’t thrive and will not become the beautiful addition to the landscape you had envisioned. With a possible lifespan of more than 100 years, it is well worth taking care of your tree.
Claire Schuchman is a Phipps Master Gardener.