I have Cooke's Pakistan Mulberry (which i heard may be slightly more hardier and longer fruit than regular Pakistan) in Zone 7a (Phila, PA... where we have hot n' humid 80F-100F average summers ... and with 25F-45F average winters [of course goes into the extremes occasionally every year; like the teens, single digits, or recently the occasional 50F-60F day with our strange new global warming ]).
I am thinking of removing the base of the tree and shipping it to my uncle in CA.
I've gotten a couple fruits every year, but every year the winter damage is tremendous.
This is a summary of generally how it grew for me:
1st year: lost 50 buds on my new plant (it was a Bush Form tree with 4 nice espalier-like trunks low on the tree from Bay Laurel Nursery i think), minus luckily 1 bud. lets say grew to 4-5ft that summer from that 1 bud.
2nd year: now at 5ft but died back down to 1 bud, 2ft off the ground. lets say it grew 7ft that summer (5ft+initial 2ft)
3rd year: now at 7ft, but died back down to 3ft. lets say it grew 9ft (6ft + initial 3ft) that summer.
4th year: now at 9ft, but then died back down to 4ft. lets say it grew 10-12ft (6+ft + initial 4ft) that summer (grew pretty tall).
5th year: now at 10-12ft, then died back down to 4ft
6th year: generally same as above (5th year: now at 10-12ft, then died back down to 4ft)
It grows then dies back alot and then repeats.
A shame really, the leaves are out of this world. huge 12"+ heart-shaped leaves.
The 1st few feet of my tree is pretty ugly from all the dieback and a new main trunk forming off the side of the true 'main trunk'.
I'd stick to Illinois Everbearing or some other stuff RainTree Nursery offers if in the states.