You have recommended Northern gardens wait until early spring to divide their rhubarb. Isn’t that too late? Can I do it in summer?
I like to give advice that will give you the best chance of success with the least amount of effort. Dividing plants in early spring as growth begins is the least stressful for the plant and usually less work for you. I have moved rhubarb plants in mid summer. The large leaves lose lots of moisture during hot summer days, stressing the plants and requiring more watering from me. Fall transplanting in northern regions doesn’t always give the plants time to recover before unpredictable winter arrives.