You are overthinking this. Plant the variety you want according to the tops and don't worry about the roots. They'll find their space and their way as long as they're in soil.

You are overthinking this.

==>> thats exactly what i was thinking.. as i was reading thru ... [this and the other post]

perhaps you ought to think of the dead roots as future compost ...

the only issue i might consider.. is that rotting wood uses water and burns nitrogen ... as as it decomposes.. watering might be tricky to figure out ... and if nitro goes down ... you will have a yellowing tree ...

but i would not try to add any fert in advance... dont fix what might never happen ... just try to remember that if you see such ... besides .. if the lawn is fertilized.. this may never really be an issue ..

that link above... that states GGs can be foundation plantings is simply put.. ridiculous ... completely outrageous ... ignore it ... its not surprising its on a website that sells the plant ...

most size estimates with conifers.. are usually at 10 years ... and you can presume.. at 20 years.. they will be twice as large in all dimensions ... to suggest that a 50 foot tree will be 8 feet wide is not not reasonable ...

conifers.. as trees.. never really stop growing ... so never rely on them stopping on some magical height or width ...

the reason there are no real pix of mature trees... is that the GG hasnt been around for 50 years .... you would have to take the two plant from the cross ... look for FOREST pix of those plants.. and then intuit between the two ... it probably isnt going to be smaller than either of the parents ....

im not sure your corner GG will stay on your property.. within 10 years.. well grown ...

ken

As noted, Green Giants are big, fast growing trees and will not remain at an 8' width for very long.....15-20' is a much more reasonable estimate of a mature width, so space accordingly. And although it really doesn't have much of an impact in this situation, there is NO relationship between the canopy spread or width of a tree and its root system. The roots can and will venture as far beyond the canopy edge/spread/dripline as they need to to seek out soil moisture and nutrients, sometimes several 100's of feet.

true I know wood chips/roots/compost/anything really sucks up nitro from soil to turn it back into compost, and yes I am planning to fertilize the soil to help that. If anything, some organic milorganite shouldn't hurt though.

Some of the old maple roots are big, like a 6x6 (more like a 9x9) is in the way of the new GGiant roots, will take a long time to decompose. I'm just hoping the new trees can root under them. The maple roots span out much farther than a GGiant will. edit, unless is true as mentioned a GGiant will span roots farther than usual in order to anchor if something's in the way (hopefully deeper too where the maple didn't root).

True I Was thinking that maybe GGiants are so new (think I read 1960ish along the way of researching) hence you don't see them so mature in home landscapes nor such large ones being removed on youtube even though they are so popular.

I know of a few hedges of these and checked them in google earth street view and noticed they aren't spaced more than about 6-7 feet but doing good, but as mentioned mine would have blockage on almost 3/4 of that corner in diagram hence I will space them out more, whereas a screen/row of these usually has free space front and back to root, and side by side they intermingle roots and share that space, plus their sideways roots possibly being smaller is a bit helped but how they block eachother from side-by-side wind.

They're leaning over because they're rootbound, have as a result not been able to anchor themselves adequately even after the amount of time that has passed since planting.

^ nah it was that the silver maple had enough free space to grow wide (instead of how in a forest, close to other trees, trees grow tall and narrow to reach canopy).

I wasn't clear. It was just 1 tree, the trunk went up about 3-4' and then created two larger 'trunks', and that crotch is where it was starting to rot because it collects rain and debris.

Even if when it was young it was pruned to grow more as one trunk, it had enough open space above that it would have created that outward span higher up in the tree with large limbs. There are a bunch others near-by that have this, limbs will either eventually fall on houses, sheds, pools, fences, etc if the tree isn't condemned and chopped down first. That's why I think near houses one shouldn't plant such large heavy trees, something instead that maxes at about 35-50' is better and still give good wildlife habitat etc like larger trees, and easier to remove and less problems if branches fall. That's what I see in newer developments- some landscape architects know what they're doing and put smaller trees, instead of how it used to be you'd see huge maples buckling sidewalks and then they chop them down, people planting giant pines next to their foundations etc. BTW for ins purposes if a tree falls on someone's property and it was a natural cause ie a hurricane, the tree owner isn't responsible, but if the tree was neglected/rotted and falls then it's the tree owner's fault, even if it was a hurricane but neglect/rot is the deciding factor, a good ins adjuster would see where the limb disconnected from and see rot since wherever a tree splits into a drastic crotch V can to collect rain and debris and rot.

I am removing these roots. Almost every resource says to just make sure to plant a few feet away, and many testimonies say their new tree is doing fine years later, but even 8ft away I am hitting like 3x3 fresh lumber I can make furniture with lol.

Ultimately I think this is a unique scenario because I checked youtube vids like below and although some of those trunks are much smaller than the Silver Maple, the ratio of roots-to-trunk size seems way different as if this Silver Maple made clusters of much thicker and longer roots for its size - I think it's because the sandy/clay grading soil when they built the development makes things root shallow in this location. This is how a lot of developments are built, they use cheap sandy/clay stuff for the main grading and then only about 18" of good soil on top for the grass and trees, and also I've heard this whole side of town was basically a swap or something once upon a time, google maps even shows a blue line (river) along this fence line but there's never been a river, maybe an underground spring or something hence the map's river line starts and ends with no body of water and I've replaced fence posts here when it hasn't rained and basically hit an underground river (the wood underground was solid because no oxygen is why fence posts usually rot at the base only).

I removed the stumps and roots of a row of blue point junipers that were chopped down like 7 years prior and they were still solid.

If the roots look like the below vids, then yes go ahead and plant close and don't even worry about that little amount of roots in fact yes it'll just add organic matter I'd prefer to leave some roots if it's sandy/clay which is what I'm doing adding small roots back into the mix and mixing the sandy sub soil with the dark rich compost topsoil.

Green giants are well-rooted and unlikley to tip over from windthrow, and they might root deeper into the sandy/clay stuff just below the old maple roots, but bottom line is there's too much big roots in the way that I know it'll be better without them, I can't even dig a 1ft wide hole for a new tree without hitting something decent. Some trees cost too much to risk it IMHO at least get some of the old roots out, setting up irrigation, transporting the trees, fertilizing etc better to not risk it if the conditions and old roots are like this. Another thing is if a previous tree/roots had disease, it could enter the new tree, but as long as there's not a ton of old root mass, then maybe it's not a big deal and the soil microbes will correct it, but just wanted to note that about planting near an old stump.

And well, you can't just make quick work of roots with a chainsaw because it'll dull in 5 seconds and you'll spend more time sharpening than cutting (although I might sacrifice a chain for this and test my dremel chainsaw bits for once because usually I just hand file), but it's not too too bad removing roots. It rained hard and turned my project into a pool that I bucket'd mostly out and then filled the finished areas back with soil and it was like working on quicksand but it's getting there and the farther away from the stump the easier it becomes. Sawsall pruning blades dull really fast too and I resharpen them on a bench grinder but it's still takes a while. I've been picking at them with an axe, splitting wedges etc, rain-soaked compost topsoil makes it a lot heavier and everything slippery, been going at it with a jack hammer with a sharpened chisel bit does decently.

This Silver Maple stump was like 3ft wide at the base. I just removed a different maple's stump and roots from the sidewalk grass strip area to plant new sweetbay magnolia and that was about a 1ft maple stump but the ratio of those roots to the large silver maple doesn't correlate, I was able to rather easily remove the whole stump and what seems like the only main roots it put out due to being confined between the sidewalk and street compared to the large Silver Maple really put tons of big roots out.

sorry so long, Another things though is Green Giants are an extremely QUICK growing tree so I would still prefer not to have even medium sized roots near them.

Tree services should offer the option to grind the roots too if they're this big.

The Silver maple roots I'm removing are much bigger for the trunk-to-roots ratio than these trees it seems likely because of the site conditions

https://youtu.be/N3RUifC7Uo8?t=310

https://youtu.be/Fjg7ieBY7Lk?t=434

https://youtu.be/bRTIwWUg4fc?t=152

https://youtu.be/vM24klVyxFk?t=477

If it were me, I'd just take the stump out.

Less problems landscaping and you won't have a mushroom show sprouting there for the next several years.

Concern: Wood chip mulches will tie up nitrogen and cause deficiencies in plants.

Evidence: Actually, many studies have demonstrated that woody mulch materials increase nutrient levels in soils and/or associated plant foliage. My hypothesis is that a zone of nitrogen deficiency exists at the mulch/soil interface, inhibiting weed seed germination while having no influence upon established plant roots below the soil surface. For this reason, it is inadvisable to use high C:N mulches in annual beds or vegetable gardens where the plants of interest do not have deep, extensive root systems.

https://s3.wp.wsu.edu/uploads/sites/403/2015/03/wood-chips.pdf

@Sally Unger Although it's been several months since your post here, I'm hoping you can answer some questions for me regarding your Green Giants. I am wondering how deep your original bed was for your 12' Green Giants and plantings? I am also considering planting green giants in our yard (1/3 acre property and planting along both our side property lines (our back property line faces a common area so I will not plant any there). Our landscaper said that we can place 6' specimens in a bed that is 8' deep and stagger them and also put smaller plants in the bed. I am very worried that these will quickly outgrow that space. In addition, I am concerned that he is planting too many: he wants to plant 18 of them up one of the sides (staggered) in an approximately 80' space, which I am worried is way too many! That being said, I might be willing to plant them if we only do one row of less trees and then add the plantings and lighting, even knowing that I will eventually have to move the plantings (and lighting), as you did. I also wanted to find out if you planted each tree 6' from the other or if you planted them 6' apart on center? Either way, have they grown into eachother and are you able to post a picture? I am very stressed that we will have a space that is too overgrown 10 years from now so I am hoping you can provide some insight. The landscaper's solution is to have him come out every year and trim them, and again I'm worried that will be way too much maintenance, plus I am looking for a more natural look. Just FYI, we are in central NJ and have a large deer population. Thank you @Sally Unger or anyone else that is willing to chime in and help!!

Stressba11 The bed is probably about 10 ft wide with the trees planted along the border. After 10 yrs the trees are about 10 ft wide...5 ft on our property and on the other side they protrude 5 ft over the property line into the neighbors yard. They are a solid hedge. They were planted 6 ft apart measuring from the trunk of one to the other. Our 6 trees are about 30 ft of space from trunk to trunk planted in a straight line. Staggering is a nice idea if you have space but I agree 8 ft will be consumed in a few years with no space for other plants. We have a deer problem but they do not eat the green giants. If you don’t need a solid hedge immediately (we did want one for screening), you can space the trees further apart. And wait for them to grow together. By the way, we planted a single green giant that was 3 ft about 5 yrs ago and it is now about 10 ft tall.

@Sally Unger Thanks so much for your quick reply! We have decided to use the Steeplechase GG variety that doesn't grow as quickly and is not supposed to get as wide so that we can put the in a bed with some other plantings. We are planning to use the Green Giant variety that you used on the other side of our yard for more immediate privacy. Your comments were very helpful in our decision, thanks so much!

We planted a row of 13 GGs on our property around three weeks ago for privacy. They were 12 feet tall and were planted 7 feet apart. I would like to plant some Limelight hydrangeas and grasses, maybe fountain grasses near the GGs, but I'm unsure how far away from them I can plant. Any advice is appreciated.