Personally I think the tree is beautiful and has a really nice shape as is.

Lets see what other people have to say.

If layered and see-through is the look you wanted, the process should have been started years ago. And would have involved staking and training of the lateral branches into a more upright form and the judicious removal of quite a few other branches.

This is really how these trees grow - a large mushroom or umbrella shaped mound. And it looks exactly as it should :-) The layered or see-through look takes a great deal of time and effort and training & pruning skill to achieve. No neglect at all - the tree looks super healthy!

Was just at a large display garden nearby today with a large assortment of Japanese maples and ALL the weeping dissectums looked very much like yours - some were shorter; some were wider and some had green foliage instead of red but all were large mounds.

Also saw the largest lion's head maple I have ever seen but that's a story for another thread :-)

Looks like 'cousin It'. :-)

If you do decide to prune that beauty you had better spend some time boning up on aesthetic pruning- you can ruin it beyond belief with one wrong cut.

Research.

And your research will also help you choose the proper time to prune which isn't necessarily now.

My husband wants to pull it out with the truck because you can't see the waterfall, I'm hoping that thinning it some might stop his bitchin' I don't want to come home and find it yanked out...

Pruning when fully leaved can make it quite difficult and what cearbhaill said, once a branch is cut it can't be put back on. So I would study web pics of properly pruned JM before attempting this.

I would approach the tree from behind and go under it with a small pruning saw and loppers. Remove the branches that hide the waterfall and any other view you want to see. Cut the branches off where they begin and leave no stubs. Leave the rest so you don't end up with a bowl cut.

Here's one of mine.

Yes you can start to prune. (certainly better than ripping it out)

A bit of study helps. Even better to consult your local nursery and start asking if someone in your area can give expert advice. Or a regional botanical garden. No different than researching a renovation on the home...not everyone knows what they are doing.

Look through google image and find some before and after shots. Find a pic that reflects what you want.

I've pruned mine that were 'mops'. And i agree that in your setting it would be nice to expose some trunk/shape. I imagine that was your original intention. What stops us from pruning is fear. When many bark how hard it is or how wrong it is.

These trees are solid and tough especially at the age of yours. And it is healthy and gorgeous.

You can take 1/5th at any time, or a bit at a time as long as temp are under 80. I prefer 60-70. I've been pruning here and there and once you start it is quite satisfying. Almost Zen-like after work for five to 15 minute setting.

I spent two years in fear of destroying mine, then just went at it slowly.

(i have three and two are 8ft tall and 20 feet wide. The mop shape did not fit our entrance...gotta get in the door.)

A small set of snips, quite small, Dramm has one pair that is just 10bucks. Just research the spot on the leaf cluster where to snip. Just start with some of that leaf weight off the bottom, then work a bit up slowly. Once some weight is taken away by all those leaves, the branches start to lift up, so going a bit at a time is best.

I'm good on snips, I've got two Felcos and a really nice needle nosed pair who manufacturer I can't remember but I love them. I can't really get under it though. It overhangs the pond by about four feet, maybe five and the trunk is right at the edge. The bulk of the tree hangs over the pond, it's lop sided shape is the reason I planted it there. I meant to keep it thinned and with a Japanese garden look but I screwed up over ten years ago and cut some major branches by mistake and then stopped pruning it at all. The trunk is nothing special. It does not have nice twists or layered branches (that is where I screwed up taking lower branches off at the trunk instead of part way up) I haven't pruned the Clematis behind the pond in several years either. I had tendonitis in both shoulders and my right elbow and nothing has been pruned much for years.

If it is hard to get to and under, maybe this is one time to hire someone skilled in JM pruning to do the job for you :-) June is actually an excellent time to do canopy thinning and lifting but it really is best to do so from under the tree.

Check with some of your local independent nurseries/garden centers - they usually have a resource folder with contact information on landscape professionals, including skilled pruners. If you were closer, I'd give you the number of my go-to guy for any JM pruning but doubt he would commute to Portland!!

I'd limb it up at the bottom to show a little trunk. Hire a pro if you can afford to, if not, do some research and prune VERY SLOWLY! Take your time and think through each cut. Step back and look at it very carefully after each cut, no matter how small.

Bungie cords help if you are trying to get a more layered look. Wouldn't attempt pruning with all the leaves as it is a valuable specimen. My husband is not allowed near it. We learned the hard way. :)

"Hire a pro if you can afford to"

After you verify their competence.

As I wrote in another thread, my next door neighbor hired someone to trim her JM and I stood and watched them do it with hedge clippers. It is now an ugly toadstool. I can't imagine many rural and small town type areas have JM pruners in the yellow pages- hell, the best nursery near me sells only Bloodgoods, Crimson Queens and Viridis, only this year they were feeling very progressive in offering a Trompenburg. Cutting edge varieties!

The best advice I have is to stare at this tree for a long time and try to visualize things twelve ways from Sunday before you cut. I only have one JM in the public area of my garden (dozens out back) and I am sure neighbors have taken pause at me standing there staring like I am trapped in a never ending fugue state waiting for either inspiration or certainty to strike. I stare at trees a lot. I lay under them, I crawl behind them. I stare during winter when I can see the structure clearly and I even take photos and make notes about limbs I intend to remove when the right time rolls around.

I might also suggest driving around your town looking for trees that have been aesthetically pruned in the correct manner. I stop at houses quite often and have never run across a homeowner who doesn't enjoy talking about how great their plants look. They could give you a pruning reference, or even come over for coffee and perhaps give you some tips and even find it impossible to resist helping.

The beautiful waterfall look you are after is in there. All you need to do is acquire the skill to uncover it.

The OP lives in Portland, OR and if one can't find a professional experienced in the art and science of pruning Japanese maples there, then they simply don't exist!! The Portland Japanese Garden even offers classes in the correct way to prune JM's.

Well, there is that. Oops, me. My own lack of anything colors my world view, lol.

I am an obsessed plant collector and horse owner, no extra funds to hire a pro. I did some grooming on it, removed dead wood and trimmed foliage up out of the water. The trunk is boring, almost perfectly straight and angled out over the water until the very top where it has interesting branch structure.

The rootball is stable, it is somewhat sheltered and has never had much snow or ice. I wish the trunk was twisty like yours but it isn't. I planted it in fall of 1995 from a 3' tall b&b. Didn't think to stake it upright but just did a couple others I have in pots. I angled it out over the pond and let it grow. There is nothing attractive behind it. I hesitate to thin it too much but it's such a blob.