Introduction to Japanese Maples

Size and Habit:

--Some people think all Japanese maples look like this:

They don't. This is a type called dissectum.

--Dissectums are small, right?.

at dissectums are small.

Relatively relatively speaking, yes, but after 30-50 years, they can be 10-12', easily.

There are lots of other kinds of Japanese maples, probably over 1000 varieties:

--Most Japanese maples are wide compared to their height, like shrubs, and branched low.

--They don't have central leaders. They have a decurrent growth habit, or scaffold structure, instead.

--They are small trees, but most are not as small as many people think. The most common height is 15'.
Yes, that's a small tree. Go outside and look around. How many mature trees do you see that are less than 15'?

--But very few are 3-5'. Most of those you see are not mature, have been pruned to size, or have been grown in pots.

--They all do fine when pruned to size or grown in pots (if you do it right). All are good bonsai subjects.

--There are only a few 3-5' dwarfs, mostly green; anything under 15' is considered a dwarf or semi-dwarf.

--The smallest are slow-growing, and don't provide much material for propagation, so they're often rare and expensive.

--Maples are relatively quick to reach half their mature height, but slow to reach all of it, which is why they're perceived as small.

--They don't have aggressive roots, won't crack sidewalks, take well to pruning and root restriction to reduce size.

--High-quality trees are almost always grafted. There's a good reason for that.

Hardiness:

-- Many, but not all, Japanese maples are hardy in USDA Zone 5. Click here for a list. The rest are hardy in zones 6-9.

-- With new or uncommon cultivars, there often isn't enough data to know for sure. If it's not on the list, we don't know.

-- We do not recommend maples for Zone 10 (south Florida, southern California, parts of Texas). They do not like warm winters. The ones at Disneyland get replaced every few years. If you can afford that, knock yourself out.

--They are not houseplants for the same reason. They need a cold dormant period and good air circulation.

--Most don't care for hot, humid southern summers, but some will do well with proper care. Click here for a list.

Siting:

-- Most don't want full sun all day. Morning sun/afternoon shade is best.

--In cool, coastal climates, full sun is ok for most laceleafs & most green cultivars.

--Best planting spots are on the north or east sides of houses or walls, or shaded by larger trees.

--Protect from strong wind.

--Deep shade will cause most red cultivars to turn green.

--Some sun is necessary for good fall color.

Planting:

--Most important factors are continuous moisture and good drainage.
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--Amend heavy, soggy soils with sand, gypsum, or bark.

--If necessary to promote drainage, plant on a raised mound.

--In well-drained, acid soils, no amendments are recommended.

--If soil is alkaline, add peat, spagnum, or other organic matter.

Care:

--Regular watering is the most important thing, especially in the first year. Keep soil evenly moist, never dry and never soggy.

--If water is hard, do an occasional deep watering.

--Water morning or evening if possible. Water at the base of the tree, not on the leaves, if sun is on them.

--Fertilize lightly, once in the spring. That's enough in most soils, especially if you....
--Mulch with organic matter in the fall, but keep mulch and soil away from the trunk..

--Use a balanced fertilizer, such as 10-10-10 or 7-9-5.

--A summer mulch of bark, rock, etc. will help keep soil cool & moist.

--A tree's roots are typically as extensive as the part you see. Water accordingly, to the drip line.

Disease Prevention:

--Maples are susceptible to fungal & bacterial diseases such as Pseudomonas, and Phytopthora.

--Most are preventable with good drainage and good air circulation.

--Additional prevention and cure involves spraying with Phyton-27.

--Phyton-27 is effective, but expensive. Cheaper measures include dormant copper spray and a bioengineered product, Serenade, available at garden centers.

--Sprays are most effective if applied just before buds open.

--Spraying is highly recommended. It's cheaper than buying new trees. We only guarantee arrival in good condition.

Pruning:

--Some people just can't wait to start hacking. LEAVE THEM ALONE until they get beyond the juvenile stage. Did you call a plastic surgeon when your teenager got gangly?

--Pruning retards root growth.

--Unless you know what you're doing (if so, why are you reading this?) prune only to remove dead or diseased branches and crossed branches, but...
--Remove any growth below the graft. Why?

--Prune back branches that block the sidewalk or hit you in the head when passing by. You don't need that.

--Optionally you can, once a tree is fairly mature, remove twiggy interior growth to show the branching structure, Japanese-style.

--If a variegate leafs out green, wait a year. If it does it again, prune out the green branch.

--When and how to prune Japanese maples is a subject of debate. Some say cut close to bud pairs, don't leave stubs, and don't paint the cut with anything. Others say Japanese maples are exceptions to these rules.

--Most sources agree that late fall is the time to do it, but....
--Vertrees, who "wrote the book" on Japanese maples, says major pruning should be done just before leafout, and corrective pruning done any time.

Variability

--Many Japanese maples change colors and color combinations throughout the year.

--Appearance is very responsive to sun/shade exposure, soil type, fertilization, soil moisture, and other environmental conditions.

-- A photo of one tree in one place at one time may not represent all trees at all times and places.

--Still, a specimen of a given cultivar should be genetically identical with all other specimens of that cultivar, so in similar environments, they will look the same.

Propagation

--Seeds from your tree will produce new maples, but NOT THE ONE YOU HAVE.
A seedling of 'Tiger Rose' will not be a 'Tiger Rose'. Why?

--Cuttings may work, but usually not well; the roots will probably be weak. Why?

--Grafting is the way to go, so if you wish to propagate your trees, you need to learn how.

--The understock for the graft is a species Acer palmatum, that is, the kind you would get from seed. You can grow seedlings to graft onto.

--Although seeds won't reproduce the cultivar you have, they may produce attractive trees. Maybe one will be so unique and attractive that you can name it, sell it, and get rich. How to start seeds

Names & History

--Most Japanese maples are cultivated varieties of one species, Acer palmatum. Acer is Latin for maple. Sugar maple is Acer saccharum. Similarly, all dogs are one species, Canis familiaris, whereas the coyote is the species Canis latrans. Other Acer species often called Japanese maples are Acer japonicum and Acer shirasawanum. These are somewhat hardier than Acer palmatum, so worth looking at for zone 5 and maybe 4.

--Names like 'Emperor' and 'Crimson Queen' designate cultivars. 'Cultivar' is short for 'cultivated variety'. Cultivars only persist because they are cultivated, not in the wild.

--The full name of a cultivar would be, for example, Acer palmatum 'Crimson Queen', with the cultivar name in single quotes and not italicized.

--Acer palmatum is variable in the wild. Most look alike, (they're green) but a few seedlings are unique. Japanese nurserymen recognized this hundreds of years ago, and started propagating the interesting ones by grafting.

--A Japanese list of cultivars exists that is dated 1710. And you don't have yours yet?

--Japanese cultivar names tend to be interesting, evocative, and poetic, as well as being descriptive of a tree's unique quality. Some English names are too, but many are prosaic, e.g. 'Jim's Red'.

--New cultlivars are now developed (or more often, found among seedlings) in many areas of the world, including Europe, Australia, New Zealand, and America, in addition to Japan.

Other Information Sources:

--The book most cited as the bible on the subject of Japanese maples is Japanese Maples: Momiji and Kaede Third Edition by J. D. Vertrees and Peter Gregory, Revised and expanded by Peter Gregory. Vertrees, now deceased, wrote the original book; Gregory has updated it to include newer cultivars.

--Another contender is Maples for Gardens, by C.J. van Gelderen and D.M. van Gelderen. The van Gelderens own Firma C. Esveld in The Netherlands, a nursery that has perhaps the largest collection of Japanese maples in the world and has introduced several cultivars.

--Both books, and a paperback abridgement of Vertrees, are available from Timber Press.