I think any organic matter can be turned into mulch. You could pile it up in a far corner and wait, or put it through a wood chipper.

I think Ingrid composted in place by leaving the trimmings chopped up under her plants.

I think rose trimmings might harbor fungal disease or pests and shouldn't be used as mulch .

can the white crust be Powdery mildew ?

Pink rose, powdery mildew maybe. I’m used to seeing it in the spring. Overwatering perhaps?
It can’t be due to rain because we have ..none.

I am also seeing Powdery Mildew this Winter for the first time on some new roses I have in pots . I think it is caused by high humidity with cool & dry weather . I sprayed Bioadvanced on the roses affected and it has been controlled .

I would never compost the leaves unless they're super clean--no rust, no black spots, no insects etc. I do save the thorniest branches sans leaves to lay on my daughter's garden, on any open bare spot between plants. They prevent the neighborhood stray cats from doing their business all over.

Pink rose, dry and cool here too but low to humidity. Maybe it has to do with the watering system? This rose gets drip irrigation as well as overspray from the lawn sprinklers. Recently their watering times changed .. could that be a factor?

Soozie, although my prunings have no obvious problems — beyond the one I raised here — I couldn’t swear that they’re pristine. So I’ll send them wherever our local collection service sends green waste.

Soozie Q -- what a great idea. Brilliant! I'd like to invite the cats to come and eat the gophers. But then they might take the birds, too...

I have such a hard time pruning all of mine because I feel like I should be trying to root everything I prune off. Which takes an enormous amount of time!

Carla in Sac

Carla, when I pruned one of my two Geranium Reds last week, I plunked four cuttings into a plastic cup. It has been knocked over by the wind twice, and knocked over another time by (crows?). I keep putting off pruning the ones I want to take cuttings of!

Sylvia, are you doing okay with the Castaic fire burning north of you?