I've never heard this...I hope not...my friend has one tree, doing very well here in Central FL...its about 3yr old, and 10ft tall. Would be very cool to see this fruiting here!
Believe it or not, my friend also got a guanabana to fruit in the ground, without protecting it ( he bought the tree at about 3ft tall, and planted it...we had no serious freezes for about 2 yrs, and it made one fruit last year)....but now that we've had a freeze, I think his luck has ran out....the tree will take a year to recover I'm sure.