I have 3 rhubarb plants in full sun planted next to my garden and are about 3 years old. The plants are all the same type. The 1st plant next to the garden has grown the largest, the 2nd plant next largest, and 3rd least largest. The plants are not very large and stalks are thin. The size and thin stalks get less robust the further from the garden the plant is situated. The smallest of the plants is very close to the alley and a telephone line box. I have bought and added cow manure compost each spring and fall for past 3 years, and this spring only I dug in and watered in a few handfuls of lime to try to improve there growth. I will water the plants deep about 1x/week when it’s not raining. Actually this year the plants are smaller than last year. What’s wrong? What do I need to do? Also this year, the largest of the 3 plants have developed a couple of hard woody looking clumps in the plants center. No idea what this is.. good or not good.