Raspberries- I have Heritage raspberries. I fertilize with all-purpose garden...
Raspberries- I have Heritage raspberries. I fertilize with all-purpose garden fertilizer and elemental sulfur each spring, since our soil is basic. I mulch with composted pony manure. Last year all of my canes started to die back, starting at the tip, right as they were making flowers. Some died back all the way to the crown. Others died back part-way. There was no sign of insects or disease. This year, the 2nd year canes are making leaves up to the point where they died last summer. The foliage looks healthy. Do you have any ideas on what may have caused this? If it was a mistake I made in caring for them, I would like to correct it, so we can get some raspberries this year. Thanks Eileen Jacobson
It's hard to know what caused this without seeing the plants. Do you have any pictures of the plants as they were starting to die back? A couple of things can cause this dieback. The raspberry horntail, a borer that eats out the middle of the young primocanes will cause the top of the cane to wilt in midsummer. If this was the cause, you can see the hollow canes from where they burrowed through. Horntail is very common in Utah County, and the USU extension website has a fact sheet on horntail identification and management. Another possibility would be heat or salt stress, this would look very different, with the leaves showing "burning" or dieback along the leaf edges.
If you can get some pictures, take them to the county extension office in Provo and see if they can help you.