lost some elms through the winter

[Dave E]

i've been going through my trees the past month to see how they survived the winter and doing some repotting.

everything seems to have done just fine except for some of the elms.

i lost a yatsubusa,a hokkaido,and 3 regular chinese elms.everyone i lost the trunks looked fine and the roots looked fine and healthy,but the base of the trees right at and just below the soil line turned to slime about 2 thirds the way through the trunk. again this only happened to the elms.
my other elms seem fine-trunks and root seem healthy,but i'm starting to get concerned that they are the only trees that the buds haven't shown any kind of activity

any ideas what this could be,assuming it's something i did i'd like to not do it again

 

[sorce]

That's what mine do with sphagnum in em over winter.

I reckon so wet....with a lot of freeze thaws.

Sorce

 

[Dave E]

i was thinking it might of had to do with the freezing temps and than days in the 60's and 70's and than back to freezing etc.. winter we had


i had a bunch of elms in small pots 4" or so which i buried in mulch for some winter protection-the hokkaido and yats were the only one in mulch that had this happen.

the funny thing is the 3 regular chinese elms were in larger pots and the only ones i didn't have covered in mulch and everyone was affected

 

[rockm]

My guess is they stayed too wet during storage. Drainage through the pot under the mulch is VERY important over the winter. I put bricks under all my pots before I cover them with mulch to make sure there is air space underneath to allow quick drainage. I also overwinter them on the flat, level brick patio.

I've also found that some tiny-leaved varieties of C. elm can be less cold hardy than the main species. I had a Catlin elm progressively croak over three years after three colder winter.