Can you not move one?

They are both over 15' tall and I haven't had luck moving any of the volunteers in the past. I don't have any other space for it either.

Could one mysteriously end up to the right of the walking path curve?

^__ This is my thinking too.

Two same species trees will grow just fine with that much distance between them.

Someday, the crown will appear to be as one tree, with two trunks coming up from the ground.

As long as they both get enough sun during the day. imho:

I say leave them both

Are the Junipers to the right of the KCT's yours? KCT's can get very large and will likely deprive them of sun. Personally, I'd take the KCT's over the Junipers.

As you probably know, they are slow for the first five years or so. Once they are established, they can grow 3'/year or more after that. I've got a KCT that was planted 11-years ago and is approaching 25', with most of that growth occuring in the past 5-6 years. They're difficult to transplant, so that's probably not an option.

KCT can make for a gorgeous specimen, but be prepared for considerable cleanup, as it seems the entire canopy is falling come cool weather. With two of them, you'll double your "pleasure."

Hi @krissamn:

You have me intrigued by the two volunteer Gymnocladus dioicus in your landscape - AND that you've unsuccessfully tried to transplant previous volunteers.

Are there some prolifically fecund female Kentucky Coffeetree in the neighborhood? Or, is some Neolithic large ruminant just an occasional visitor, making a deposit?

Inquiring minds from the central Kentucky Bluegrass region - home to some great KY Coffeetrees - want to know...

I could have given more detail. I had a KCT that died about five years ago. It was the first tree I ever planted, Prairie Titan ordered from Klehm's Song Sparrow. Unfortunately, I didn't prune it well when it was young and it split in a storm. I've had a lot of babies that I tried to move and none made it. These two sprouted in a good location and seem to be thriving right now, 15' and 20' in 3 years. I'm being pretty aggressive in my pruning because of what happened to the parent tree and trying to avoid the honey locust as much as possible. The tree in the middle is clearly getting less sun, it's shorter and 1/2" smaller diameter. All the trees are closer to the house than ideal.

I appreciate all the feedback and suggestions and am glad I asked before taking action. I'm going to keep it.

Are these trees the general KCT or Prairie Titan? Either way they are my favorite trees. I have seen them planted a lot more in city plantings around Minneapolis and it makes me happy

Maackia, I agree, the juniper will for sure go before the KCT. It keeps getting split in the winter with snow load and I was surprised it bounced back as well as it did this summer..

Thank you for the additional information, @krissamn. That confirms what I suspected.

Your original tree - Prairie Titan - had grown in your landscape long enough to establish a healthy root system that persists despite having lost its original above ground trunk and crown. This root system is continuing to put out new stems to grow new leaves in an effort to keep itself alive - a survival strategy of many woody plants that are termed colonizers.

With closer examination of some of the youngsters you previously tried to transplant, you would probably find just that kind of evidence: a new stem emerging from a horizontal root, and not much else. It is pretty hard to get that to survive, when separated from its parent structural system.

So: your two trees are likely dual stems from a shared root system. Trying to eliminate one will cause additional suckering (attempting to recreate leafy surface for photosynthesizing), and confounding your attempt to have only one "tree". Worse: if you tried to kill the additional stems with anything like a nonselective herbicide, you would damage and/or kill any conjoined part you were trying to keep.

Prairie Titan - as a male clonal selection - is grafted onto seedling KCT understock/root systems. Your new stems are going to be genetically identical to the original understock - not to Prairie Titan. It will be many years in the future that you may get to see these stems flower, and then be able to tell whether the understock was male or female.

I have five Prairie Titan planted around here at the Valley, now approaching about 25 years of age. I have not lost any of them to storms or anything else, but anywhere that the roots roam and that I've disturbed them by planting and cultivating, there are KCT sprouts. It is an annual (or more frequent) effort to nip them off and discourage additional trunks in unintended places.

Here's one of mine from 2012, surrounded by Bottlebrush Buckeye at my front walk. There are regularly occasional sprouts in planting beds up around the porch in the right background, and amazingly I find them more than 50' feet away in more remote Viburnum collection plantings.

I can attest that KCTs like to sprout from their roots, but it usually seems that a happy established tree does it relatively little. Cut one down tho, even a small one, and sprouts will usually occur in alot of spots.

ViburnumValley, thank you for all the info. That totally makes sense now why they all died. I'll wait in anticipation to see the sex of my rebirthed favorite tree. 

Beautiful Prairie Titan, I'm not familiar with bottlebrush buckeye but it's so pretty at the base of the tree.