Reuben Blackberry

Question

A couple of weeks ago I bought a Reuben Blackberry plant and I noticed strange red spots on it. Now the leaves are beginning to turn yellow and dry. I used Natural Peat for this plant (local gardeners recommendation).

Answer 1

The simplest explanation for the yellowing leaves is transplant shock, which is very common in the first few months after transplanting:

https://www.gardeningknowhow.com/plant-problems/environmental/learn-how-to-avoid-and-repair-transplant-shock-in-plants.htm

The red spots could be caused by Blackberry Purple Blotch, a disease caused by Septoria fungi, especially if the spots are/were present on the stems as well:

http://whatcom.wsu.edu/ipm/manual/black/purple_blotch.html

Alternatively, the symptoms for Anthracnose might also match for the spots:
https://plantdiseasehandbook.tamu.edu/food-crops/fruit-crops/blackberry-dewberry-and-boysenberry/