I believe my rhubarb plants are too overcrowded as most of the stalks are very thin. Could you please tell me what time of year I should thin them out and how I should go about doing that?
The Gardener’s Answer
Hi, Kimberley: How long has your rhubarb been in the ground? This cool-season perennial vegetable can grow to be overcrowded but this usually takes several years. So depending on how old your plants are they may need to be divided. If they have only been in the ground for a couple of years it may be a nutrient issue; you can have your soil tested to determine if it’s lacking essential nutrients. An indication of crowns being overcrowded is the stalks reducing in size so this indeed may be the issue. The best time to divide your rhubarb is in the early spring as soon as the ground can be worked. When the time comes, take your spade and gently lift the plants from the ground, shake off the soil, and divide them into apple size pieces. It is always best to have a plan before you start breaking the crowns apart. It is not an exact science and you do not have to be nice about it; rhubarb is a pretty tough plant and will take some man-handling. It does not matter the method of division, you can use your hands or a tool, whatever is easier for you. Each new plant should have at least one bud and undamaged roots. Get them back in the ground as soon as possible and treat them as you would any new planting. Do not harvest them the first year and only lightly the second; the third year and the following years after you can harvest up to one-half of the stalks. The rest need to remain on the plant so the foliage can store nutrients for the crown. Over-harvesting can also result in thin stalks.