Ninebark propagation thru cuttings

Hey all!

I’ve got a couple of Amber Jubilee Ninebark shrubs I’ve been trying to propagate for personal use. I’ve tried putting them in potting soil, a peat/pearlite combo, and finally sand. They all seem to suffer from rot at the base which tells me the medium is too wet. Seems like sand is working the best, but there’s still rot at the base of some. It’s likely that the sand is too wet and shallow (2-3”).
* I should add that I used a rooting hormone and a plastic done on all trials. These were places under LED grow lights in the basement.

Unfortunately it’s a little too late in the season for softwood cuttings.
Next season I’ll try again with sand, but I’m going to use a deeper tray.

Would love to hear any advice you guys have!

Thanks!

Posibly try some without dome covering so that surface of the sand can dry and not be a source of infection.  I had the interesting experience of receiving a fig tree rooted in biochar. Easy to root of course but the quality of the roots was outstanding and it adapted to the transplant without any set back.