Cork Bark Elm advice needed.

[GrampaMoses]

Hello, I have these 2 cork bark elms. The one on the left I've had for 3 years, repotted and root pruned 2 years ago. The one on the right is a root cutting from that repot, so it's 2 years old since the root cutting. I haven't pruned or repotted either since then. I was planning to repot both of these this spring, but was waiting for buds to turn green.

As you can see, everything is growing (even my tropicals are outside) but these have not woken up yet. I've done multiple scratch tests and found some twiggy branches to be dead, but other larger branches to be green. No buds have turned green yet. My conclusion is that I didn't winter them properly. I thought they were cold hardy to zone 5, so I just stuck them under my skirted deck and thought that would be enough. Next year, they'll go in my garage for extra protection.


Dead.


Live.

It's been very rainy here lately, and I'm wondering if it's safer to just stick them outside in full sun and ignore the rain, or if it's better to move them indoors by a South facing window and under a 1000W LED grow board. That way I can control the watering better.

 

[BrianBay9]

I would leave them outside. There's nothing you can do but be patient. Some of my elms are the last of my trees to get moving.

 

[River's Edge]

View attachment 300504

Hello, I have these 2 cork bark elms. The one on the left I've had for 3 years, repotted and root pruned 2 years ago. The one on the right is a root cutting from that repot, so it's 2 years old since the root cutting. I haven't pruned or repotted either since then. I was planning to repot both of these this spring, but was waiting for buds to turn green.

As you can see, everything is growing (even my tropicals are outside) but these have not woken up yet. I've done multiple scratch tests and found some twiggy branches to be dead, but other larger branches to be green. No buds have turned green yet. My conclusion is that I didn't winter them properly. I thought they were cold hardy to zone 5, so I just stuck them under my skirted deck and thought that would be enough. Next year, they'll go in my garage for extra protection.

View attachment 300505
Dead.

View attachment 300506
Live.

It's been very rainy here lately, and I'm wondering if it's safer to just stick them outside in full sun and ignore the rain, or if it's better to move them indoors by a South facing window and under a 1000W LED grow board. That way I can control the watering better.

View attachment 300507

If the soil is free draining and not accumulating water inside, then I would place outside and allow nature to take its course. If you have concerns that the soil is too moisture retentive or compacted then protect from rain but still leave outside would be my advice.

 

[MrWunderful]

Not sure what overnight lows are like in OH, but I would leave outside 100%. Arent Chinese elms hardy there?

 

[GrampaMoses]

Thanks for the thoughts.

They're planted in a variation of Boon's mix: Napa 8822, pumice, and lava rock.

SW Ohio winters can get as low as -20F, so I'm thinking during the worst of our winter, it must have damaged the roots of these two trees. Currently, it's 36F-42F at night, but we have one more frost coming soon (I'll move all my trees into the garage that night).

I decided to cut the tie down wires and check the roots. They were black and slimy, smelled bad, and fell apart to the touch. Other roots seemed fine, so I'm hoping it can recover.



I guess I'll put them outside in full sun and make sure not to over water them while they recover.

I put them back in their pots and haven't done anything more to them.

Can I do a light repot now? (Removing only dead roots and putting it back in the same pot with a little fresh soil at the bottom.)

Or should I wait for green buds to finally show up before messing with the roots?

 

[Shibui]

I don't think a root trim would hurt now, even though they are having problems. Spring is when I prefer to repot Chinese elms here but later seems to be better than earlier so your emergency repot probably comes at the best time of year. Good luck.
There are some growers over here that don't bother with Chinese elm because they get occasional dead branches. I haven't had that experience often enough to worry about.

Some of my elms are the last of my trees to get moving.

Interesting to read this. Chinese elms are the first to start growing here - assuming cork bark refers to the corky bark Chinese elm? I start to see green buds from mid winter on the Chinese elms. Other species can be later though.

 

[BrianBay9]

I don't think a root trim would hurt now, even though they are having problems. Spring is when I prefer to repot Chinese elms here but later seems to be better than earlier so your emergency repot probably comes at the best time of year. Good luck.
There are some growers over here that don't bother with Chinese elm because they get occasional dead branches. I haven't had that experience often enough to worry about.


Interesting to read this. Chinese elms are the first to start growing here - assuming cork bark refers to the corky bark Chinese elm? I start to see green buds from mid winter on the Chinese elms. Other species can be later though.

Sorry, there are other elms with corky bark. I didn't realize you were referring to Ulmus parvifolia specifically. Yes, my Chinese elms come out early. Several American else can bud very late.