Thanks for the question.

I need some clarification in your picture.  Is it correct that this picture was taken about three years ago?  I ask this because the three evergreens present are all living. 

If my understanding of this picture is correct, which two were removed and which one is still living?  Please be very specific in your identifying the relevant locations.

What I also need is a new picture showing what this site now looks like.

Also I need a closeup picture of the needles of the one surviving tree.

By the way, there are two different evergreens in the picture you sent.

Thanks for your anticipated response.



It looks as if you intended to respond to my questions but nothing was transmitted.  Please attempt again.  Many thanks.

Here are more specific pictures taken today. There were three of these but the other two turned brown and we dug them out. 

Thanks

Thanks for the new pictures and clarification.  Just two final questions if you don't mind.  

1).  Were the two trees that died and that you dug out, in the same garden (rock mulch) as the surviving tree?

2). If the two trees that died in this same garden, how far were they from the current surviving tree?

For your information, this surviving tree seems to be a red pine.  You can quickly see if this is correct.  If in a single needle bunch there are two needles, this is a red pine.  If my ID is correct, I would guess that the two trees that died were also red pines.

Yes they were in the same rock area and spaced out approximately 4 feet apart

Do have any ideas why the other two turned brown and died and do you think we should replace with same or choose something different? Any suggestions?

Thanks for your latest response. I now think that I have a good idea as to what happened and can make suggestions for moving forward.

Here are my thoughts and conclusions:

1). The three trees that you planted were all Norway (red) pines. Two of these have now died with one still surviving. Since they were in proximity to one other, I have ruled out disease or an insect pest as being involved. If disease and/or insects were factors, I would have trouble understanding why one is still surviving. I would expect that the underlying soil is fine.

2). I believe that the reason why the two pines died was a combination of insufficient water and/or heat stress. Red pines are very susceptible to these two things. I also think that these were contributing factors to the tree deaths that the previous owner experienced. I would disagree with him that excessive water was a contributing factor.  Remember that red pines are trees best suited to cool conditions.

3). I have concerns about where you planted these three pines. Rock mulch can get hot when exposed to sunlight and can elevate the temperature of the underlying soil. It currently is not recommended. See:

https://www.johnson.k-state.edu/lawn-garden/agent-articles/miscellaneous/rock mulch a solution or a problem.html - :~:text=Rock mulch contributes to the,health as the mulch decomposes.

https://www.ag.ndsu.edu/yardandgardenreport/2016-06-30/mulch-madness

4). I wonder if underneath the rock mulch is some type of fabric or plastic layer? At one time, this was common practice. If so, this would be a barrier for water to trickle down to the roots of the pine. This would only exacerbate dehydration and heat stress for the pines.

5). My conclusion is that when these three pines were planted, two of them – the ones that died – were not properly planted. This combined with heat stress and lack of sufficient water led to their demise. The one surviving tree was planted correctly though may still be stressed by elevated temperatures and/or water deficiency. It is hard to predict what its future might be.

Suggestions:

1). Immediately determine if there is any type of covering over the soil under the rock mulch. If there is a covering, removing it would be a huge task. At the very least, remove as much of this covering as possible in any sites in which you would like to do future plantings.  By all means, remove this covering around the surviving red pine out to a distance of at least three feet from the tree.

2). If there is no underlying covering, the rock mulch would be acceptable if there was a good watering system for the garden. This should involve ensuring that any plantings in this garde receive at least two inches of water per week.

3). Plantings under this rock mulch might be more successful with plants that are not as heat susceptible as red pines. See:

https://www.gertens.com/blog/top-ten-drought-tolerant-plants.html

https://www.cbsnews.com/minnesota/news/drought-tolerant-perennials/

4). With respect to the one surviving red pine, don’t attempt to move it. I doubt that it would survive. For this current growing season, just make sure it is extensively watered. This would be of particular importance during the upcoming fall months.

Good luck. I would appreciate receiving any questions/thoughts that you might have.

Thank you so much for your detailed answer and explanation, all very helpful! I looked under the rock and you are correct, there is black plastic.

I am sending a closer picture of the existing pine needles. In  another message you mentioned how to ID a red pine and that in a single needle bunch there would be two needles, but I’m seeing 4-5 needles.  Are there different variations of red pines? Shrub/Is this one a dwarf or miniature?

Also, are there any heat/drought tolerant evergreens? We were hoping to have something to provide privacy in this area.

Thanks again so much

Connie

Thanks for your response.  

Based upon your comments, you do not have a red pine.  All red pines have two needles per bunch.   Nor do I think you have the standard, "run-of-the-mill", Minnesota white pine.  It is, however, some other species of white pine.  I strongly suspect that it is a non-native tree with respect to Minnesota.  What all this means is that my previous response to you needs some modification.  I have sent your pictures to a few other Master Gardeners soliciting their assistance in identifying this tree.  It may be that the answer to your original question as to why the other two trees died is simply the wrong type of tree was put into the garden.  That is why an accurate ID of what you do have is now important.  I will be back in touch with you as to what I find out.

Thank you for confirming that there is black plastic under the rock mulch.  I feared as much.  This suggests that this particular garden was probably put in ten to fifteen years ago.  Trying to remove all this plastic, however desirable that might be, does not seem reasonable from both financial and effort perspectives.  Having it remain in place just means that you need to increase your watering efforts along the lines I previously suggested.  Also as I earlier suggested, with any future plantings in this garden this plastic should be removed from the planting area.

Thank you for both your cooperation and patience.  We will get to the bottom of things!

Good morning.

After consultation with other gardening colleagues, it is our consensus that you have an Eastern White Pine (Pinus strobus). It is a particular cultivar (or variety) for which we cannot arrive at a precise identification. Possibly it is a “Fastigiata” or something similar. See the following:

https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=g950

https://trees.umn.edu/eastern-white-pine-pinus-strobus

It is also our feeling that the presence of rock mulch and/or the black plastic covering have caused the loss of trees, both recently and for your previous owner. Due to their presence as well as high temperatures for the past few growing seasons, heat stress and desiccation occurred in the trees. White pines are not well adapted to deal with these conditions. We believe that it will only be a matter of time before your existing pine will show evidence of these stresses and will need replacement.

Previously I sent to you some suggestions for heat tolerant shrubs that you might consider. If you are looking at a possible evergreen, junipers or arbor vitae might be good choices. Might I suggest that you take a visit to the Minnesota Landscape Arboretum? It is not too far from you. They have a wide collection of trees and shrubs for you to look at.  One or more of them might meet your requirements. See:

https://www.minnesotawildflowers.info/shrub/common-juniper

https://www.nwimn.com/arborvitae-in-minnesota-thriving-evergreens

https://arb.umn.edu/

Then there are the issues of rock mulch and the plastic covering. Complete replacement is probably not in the cards for you. Identify the various places in the garden where you would like to do some plantings. In those areas, move the rock mulch aside and remove the plastic covering for an area of three to four feet in diameter. Do your plantings. Then either put the rock mulch back or instead use some decorative wood mulch. A wood mulch area within a larger rock mulch area might add an interesting visual touch. I’ve seen this done in other similar situations.

Give all this some thought and certainly feel free to get back to us with any additional questions. Good luck!!

Glad to have been of assistance.  Enjoy the Arb.  Tell them what you are looking for.