Question about rooting tree-form Geraniums

Question about rooting tree-form Geraniums

Hi, I have some 3 year old Geraniums that just this winter started going into the tree form. Not sure what the technical word is for it, but they started growing huge, vertical and with a texture of green wood. I have seen them growing outdoors like this as hedges in California before and didn't realize the regular storebought Geraniums could do it too. A few weeks ago a cat snapped off a couple of the vertical branches and I went to root them and discovered they won't root in water. Never had any trouble with the softer/earlier version of these. Could someone instruct me as to how to salvage these otherwise healthy stalks? They're pretty big and they like the water OK but I can't leave them on my kitchen counter forever, heh. Thank you!
Sunroot  / Jerusalem artichoke

Sunroot / Jerusalem artichoke

Holy Crap! What the …

Holy Crap! What the …

Welcome to My Apartment

Welcome to My Apartment

Wild Child

Wild Child

Black Forest Cake

Black Forest Cake

Weed ID

Weed ID