My first foray into backyard gardening was the 12-foot row of raspberries that came with the house. We moved in in mid-September (1997), and were surprised to be picking raspberries through the end of October. We were equally surprised to find the same canes produce an early summer crop the following June.
The previous owners had planted a mono-crop of Summit, an ever-bearing (or fall-bearing) variety that fruits near the top of new canes in the late summer and early fall, and on year-old canes the following spring. I've since supplemented the row with Golden Summit and Dinkum, along with Tulameen, a summer-bearing variety (fruits only on year-old canes), to fill in the gap. Combined, we enjoy a five-month season of fresh, organic raspberries.
That said, the fall crop is normally a bit of a disappointment compared to the summer, as the ripe berries quickly mold with botrytis under Seattle's relentless rains. Not this year. So far, our unusually dry September has left the raspberries virtually botrytis-free.
It's hard to quantify, as the bulk of the raspberries are eaten right out of the garden; those pictured above went straight into my mouth, and the vast majority of the berries travel no further than the length of my daughter's arm. But this 12-foot row must produce hundreds of dollars of organic fruit a year, with relatively little input. I highly recommend growing raspberries to anybody with a sunny, well-drained spot in their garden.