I suppose it would work. it is done commonly around my area with dogwoods, that typically are old growth.

What you are talking about is commonly done in nurseries to produce multiple trunk trees, white bark birches being a prime example. You would need to choose trees with similar growth rates, shapes, and ultimate size. And start with individuals that are the same size at planting, so one won't have a size advantage over the other(s).

when spacing.. i would look to trunk width at 10 or 15 years or so ... and plant them close.. but far enough apart ... that the trunks dont squish each other.. over the years ...

when you get into these weird experiments .. just go for it ... be the first ... as i have said many times before.. i have had many garden shows in my yard.. a couple nationals ... the things that excite peeps.. are the unusual things ... not the run of the mill... which they saw in every other garden they toured ...

what ken said as to matching size potential ...

ken

I accidentally planted two small Norway spruce seedlings in the same hole a few years ago. I had a bucket of seedlings and grabbed two without realizing it.

Now the "twins" are doing well, but it occurs to me that perhaps I should dig one of them out and plant it elsewhere, maybe this fall. So my question is the same as the OP's. Am I condemning these two spruce to death if I leave them where they are? It seems like this must happen in nature sometimes.

Thanks for the responses. So it sounds like it might work... but what trees to use? I am in a zone 5 area. Anyone familiar with some trees that might fit the requirements?

How much sun does your location get?

Is it wet or dry?

If it gets some shade,

How does Cornus florida do in your area?

Cornus kousa is the back up if florida is having issues.

Both might be a bit over planted but for good reason.

It would be full sun all day. I am in SE Idaho so it's a dry area, but it would get plenty of water as it would be planted in my lawn and would be getting the sprinklers every few days.

I am not a sprinkler fan and do not want to sign you up for much work here so I will defer to those who are familiar with Idaho. They may need go onow your elevation btw.

My sprinkler concerns are:

You have to pay attention to the ph of your water if it is the primary source for the trees

What if my home's previous owners planted a shingle oak which required watering to survive here and they did water it? There would have been an 80 foot tall tree in my yard which would have died ($$$$ to remove) or I would have to just turn on my hose all summer to produce that much water.

Some areas have water shortages and eventually you may not be able to water (not here though, my neighbors build in the path of the rivers like idiots).

I water newly planted trees for one month, every day that it does not rain. Then they are on their own. I never water the lawn.

if you are going to plant two together you might want to go with something small.

cercis canadensis planted beside cercis canadensis 'royal white'

cornus florida planted beside cornus florida 'rubra'

cornus kousa planted beside cornus kousa 'satomi'

prunus x yedonesis planted beside prunus x incamp 'Okame'

see what you think of those.

Thanks for the ideas for the trees. Yeah I would prefer smaller trees. And the color isn't as important as the contrast between the two colors. Ill have to investigate those and see if they will grow around here.