Does anyone know ???

I have a hedge (who doesn't) of Caragana wrapping around the North and NW edge of my yard I just discovered the seeds are edible ...anyhow I can't find any info on how long they last the house has been here since 1915 we've been here for 4 years so I don't know how long this Caragana hedge has been here I find it easy to pull the branches right out of the ground with the greatest of ease so likely there is some root rot going on it was 12 feet tall and 15 feet wide when we moved in so I cut it all down to 5 feet wide and 6 feet tall . I like the hedge and it produces amazing piles of composted material right within root branch foliage . I'm pretty sure I can use it for my garden because Caraganas take nitrogen from the air and provide excellent nutrients for nearby plants. The material in which it (its own leaves and seeds) grows is soft like a pillow so its very useful material and also the hedge gives us great privacy ...I'm not sure if Caragana was ever meant to be cut so low but I like having it around, but I am both concerned and curious about how long the hedge will live the best I could find on the internet was, 'average'... whatever that means .