I would leave them alone, unless someone wants to come pay me for them! However, as you said, it's doubtful.

I was just curious if there's a market for rare second hand japanese maples.

Not sure how "rare" they might be.........the photos are not detailed enough to see the trees close up but they look like your common weeping laceleaf maple. In my area, these are in just about every garden in one form or another.

Yes, they are very valuable. A couple of years ago a guy was selling his mother's house and wanted to get rid of the JM in the front yard. This tree had to be growing for a least 10 - 12 years. It wasn't huge but it was a nice size maple. I was the first to jump on it. I tried to pull it out with my truck and a strap. Nothing was budging that tree. I tried for about thirty min. To make a long story short I didn't get the tree. The roots are so deep it would have taken a backhoe to dig it up and transplant. I'm telling you this so you know that someone would have to bring a backhoe of some sort a dig it up. Not sure if you want that on that beautiful lawn. Just saying :)

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The actual 'value' is relative. Uncommon cultivars or those that have been trained/pruned with a great deal of care and have reached a significant size will be of greater value than an ordinary weeping laceleaf, which are a dime a dozen in many areas. And that has to factored against the costs to dig and move, which can often exceed the value of the tree itself!!

It is only worth what someone is willing pay :-)

Okay the JPs are staying! :) They will add value to the backyard. It was convincing to hear a truck couldn't pull up the tree. I was thinking - maybe I could sell off these trees and pay for the new patio - but now I know it won't be possible. I don't think these trees have been pruned in a long time. They are dwarf lace leaf maples. They could use careful pruning. That will be another question for another thread later - how to prune a japanese maple.

"I was thinking - maybe I could sell off these trees and pay for the new patio"

Not unless it was to be a very inexpensive patio :-) It is difficult to determine the exact size of these plants from a distance photo but unless they were really mature and had been very carefully trained and pruned over the years, they are likely not worth more than a few hundred dollars each.........if you could even find a buyer willing to go to the expense and effort to dig and transplant. As stated, these are dead common trees sold everywhere, even at the box stores!!

FWIW, any future questions about these trees would get a much better response on the Maples forum. it is far more active than this forum and focuses on the plants themselves rather than the concept/design of a Japanese garden, as is this forum's intent.

The value is reticent to the cost of the house. They are not overly valuable on their own here I owuld pay between 50-150 at just about an garden center for ones a little smaller but if the one in the back is a full grown tamukeyama I would think it would be a 500$ tree, if it is a standard bloodgood then its a 60$ tree but it does look to be a weeping variety. It really depends on your location and income area. You look like your in the northeast so I don't know. I would say this, think about having a nicely manicured lawn like yours and then take away the nice grass, japanese maples, and boxwoods and you depreciate your house value instantly by 15% of your houses net worth...

Thanks for identifying the species of the tree. That means a lot. They are old trees. I know I can't uproot them or relocate them. But they have a lot of value to me. We'll be landscaping this yard and I love all the old growth trees and plants.