I'll jump in, but anyone with more detailed and technical info feel free to offer a better explanation :-)

Few Japanese maples are offered on their own roots. That is because seed grown maples will typically differ from their parent(s), so if you want a specific cultivar, it will be a grafted specimen with the graft taken as a cutting from a known cultivated form. That will ensure a true genetic copy of the desired plant.

The difference between a high and a low graft is usually relegated to weeping or laceleaf forms - the higher the graft, the more upright the growth habit will be, at least initially. The lower the graft, the more domed, mushroom-shaped the plant will be. With upright growing forms, the placement of the graft is not so critical although low grafted uprights also tend to generate lower branching as well.

Zone 5 is often considered borderline for many cultivars of JM's, although this forum certainly has enough folks who are able to grow at least some successfully in that climate. But Acer palmatum is only one species of Asian maple, many of which are significantly hardier in colder climates. I'd look also to A. japonica, sieboldianum, tegmentosum, truncatum or tschonoskii.

Garden gals explanation is a good one...you are pretty far at the top of zone 5 even if you are in southern WI so it will be tricky ...you might want to give your exact location and maybe someone here with experience form your area will be able to suggest specific stuff...since as has been said many times zones are not a perfect way to choose... you must also consider the location of where you plan to plant and how much protection that will afford and your willingness to heavily mulch and protect them, or simply keep them in pots...
Most "collectors" consider low grafts best and preferable on uprights and hate and won't buy high grafts on said uprights...I do not know why??? ....but on weeping types high is preferred and as Gal said necessary for their form. Some growers graft high to advertise BIGGER trees which is I think a crock EG: 3FT JM TREES!!!! 2.5 feet of root stock and 6" of your actual tree;>) David

No more detailed or technical, but I can add a little:

Producing maples for the masses is an economically driven venture. There are many cultivars that are very difficult to propagate via cuttings with high failure rates the rule, and as Pam noted, seedlings are a crap shoot. This is one reason that many cultivars are grafted. Another reason is cold-hardiness. Grafting to a more hardy understock expands the market area and allows the use of scions whose roots might not be as hardy as the understock.

Upright growing plants are usually grafted low, at the basal flare, to help camouflage the transition in bark color and texture at the union. This would also be the case for cultivars that are grown specifically for the appearance of their bark. Trees with a shrubby habit can be grafted low or high, on a standard understock - usually two or three year old seedlings or cuttings. Those grafted low, might have a vigorous side branch pruned to the vertical and lower branches removed if a single trunk or added height is desired for sales appeal. Those grafted high include the forms Pam mentioned, the plants that tend to weep or grow with a congested habit.

Al

Usually Japanese maples with high grafts are weeping dissectum varieties. Grafting high allows the plant to achieve the "mushroom" shape that many people like more quickly. If grafted low, a weeping variety often will have to be staked and shaped to create an more upright leader, which otherwise might tend to grow more sideways. However, a plant with a low craft also can by shaped to an interesting form with care and proper staking. Another reason why low grafts might be desirable is the appearance of the trunk. Often the base stock that varieties are grafted onto is green, whereas the scion that is grafted onto may be a red variety that could look mismatched until the trunk finally turns gray. Also, as trees get older, often the graft juncture will swell and perhaps look kind of funny if higher up on the trunk. Those might be some reasons why low grafts are considered more desirable by some.

I thought that's what I said. ;o)

Al

Here's the deal--no explanation will be given as it is too much an inflammatory topic.

The propagation of maples is economically driven--therby grafting produces the highest yield and brings a larger plant to market faster. This has already been said and is true. For someone who just wants to enjoy a few maples, it either does not matter how the maple is propagated or it matters a great deal--that is up to you.

A palmatum grown in zone 5 will be be risky on its own roots (by this I mean a cutting-grown cultivar or variety) until it has a good root system and is of some size--this could be as many as 7 years or more and good luck finding a cutting grown plant. It will be the strongest in the end if grown correctly.

From there, rootstock and graft quality being equal, as well as scion heath, the closer to the soil line--the stronger the resulting plant and the longer it will live. It is more likely that a maple grafted near the basal flare and staked or trained upward will live a longer life, maybe much longer, than the same variety grafted on a tall standard (a tall graft)---other factors being equal.

MJH

Thanks for all the replies and info. I know that growing the maples here will be difficult. Mountain maples has some recommended zone 5 cultivars and I received some good input from the Wisconsin forums. I'll also be growing a Korean Maple or two to help ensure something survives.

Thanks again

Think down the road to the point where your tenderly-cared-for weeping dissectum type is large enough to be opened up to reveal the trunk structure for added interest. Do you want a straight stick with branching going off sideways at about 24", or do you want a trunk that diverges into major scaffold branches all the way up? Bulk buyers demand the high grafts because it cuts several years off the interim between grafting and retail readiness, and buyers demand the resulting economy. But the most valuable specimen-sized dissectae I have seen -- one a 15' wide Watnong and one a slightly smaller Garnet -- have very interesting structure from the ground up. Result? Over $1000 increase in price offered by a specimen broker because of exceptional underpinnings instead of a straight trunk.

But the most valuable specimen-sized dissectae I have seen -- one a 15' wide Watnong and one a slightly smaller Garnet -- have very interesting structure from the ground up. Result? Over $1000 increase in price offered by a specimen broker because of exceptional underpinnings instead of a straight trunk.

Silvervista ... I assume you feel even dissectum/weeping varieties should be low grafted 2-6" from the base??? ( unless I'm reading your above statement incorrectly) similarly to uprights...I have not heard this but is is interesting ...please illucidate...David

That's correct! The only drawback is that the scion would then need to be staked for several years to gain the height that the tall-graft started out with. And careful attention to placement and pruning of low branches so they help form a strong and graceful framework.

If it would ever stop pouring rain (no end in sight, and flood watch on all our rivers right now), I would get out while the trees are dormant and get photos. The difference is very clear cut -- graceful interplay of lower structure vs. straight pole with mushroom on top.

Value aside, and from an aesthetic perspective only, I agree that movement in the stem is to be much preferred over a staked standard. A string-straight stem that suddenly develops movement 3 or 4 ft above grade looks very contrived/unnatural, not just in Acer, either.

Movement can be introduced in stems of surprising caliper in a number of ways, and the movement need only be subtle to have the desired effect. Trees up to 1/2 inch diam can be wired temporarily like bonsai. Low side branches can often be utilized to introduce movement by training them to near vertical and removing the young tree top. Creative stake placement can be used to train a tree in one direction & a second or third stake can be used to change direction and create movement. Trees can be tied to stays to create movement.

Bending techniques are best set in place at the onset of bud movement & watched carefully for signs of damage to cambial tissues (from fastenings). Remove or relocate fastenings a short distance from the original location before damage occurs.

Approach grafting the trees own branches is a simple and foolproof way to insure appropriate branch placement if no branch occurs at the desired location.

Forgive me if you guys knew all the above. I'm new to the forum, but not to trees & I might be too eager to contribute.

Al

Silervista...yes post some pics when you get a chance and thanks Al for your innovative ideas... I have an older weeping disectum ( name unknown I think they just called it a cutleaf japanese red maple ;>) )about 10+ years it lost most of its lower branches from shading by the upper ones and since it a high graft?? ( it may not have been grafted I can't tell now and in the "olden" days around here none were grafted ,just seed grown, and available locally THEN ...the first grafted JM's I saw around here was about 5 years ago )Anywho whether it was a high graft or just trimed up as such.... it is a beautiful tree but has that weeping unbrella look about it .... I assume with proper trimming and a LOW graft the lower branches and leaves can be kept??? which would make for a much more "natural" look...and since even with some shading and dying branches the overall weeping look would be much closer to ground level and therefore NOT so unbrella like ...GOOD ideas thanks David