HI all,

Hoping someone can give me some insight here.

As an experiment, I'm trying to root some Rubus glaucus cuttings that I obtained. I've had them for about four weeks rooting in a soil-less mixture, under natural light here in Indiana (so, about 9 hours of daylight right now), and with a plastic bag over them for humidity. (Rubus glaucus is a tropical species, growing around the equator at high elevation.)

Both of these in the picture have indeed actually rooted, and each of them also started to send out leaves. About a week ago, I pulled off the bag, thinking that maybe they could use a bit less humidity now that they'd started to root. The problem is that, within the last few days, both of the canes are turning a darker brownish-purple color (see pics).

I'm not sure what's causing this. It doesn't seem like the canes are rotting, as they still seem firm. And indeed, one the one cane that still has green, it seems the brownish color is progressing from bottom up.

What do you think is happening here? Is this just the canes moving into some kind of maturity, or dormancy, or what? Or is it a disease?

I realize Rubus glaucus is an uncommon species to ask about, but was hoping someone would have insight.

Thanks,

Josh