Can an orange tree be saved?

[OriginalGeek]

We live in Orlando. Grandpa has had an orange tree in his backyard for probably 30 years or more but it hasn't produced any usable fruit in at least 5 or 6 years - maybe more. I only recently started paying attention. Now i wish I had paid more attention sooner but there it is.

So is there hope? Start over? Grafting? This will be my house some day and I would love to have some fruit trees. Or even one.

There's a grapefruit tree down in Nokomis that my other grandpa planted on the day I was born (52 and half years ago) and it seemed to be thriving the last time I drove by (that property is no longer in our family but I pass by it on the way to my uncle's house so I can still see it and remember good times)