When I started my garden three years ago, rhubarb was one of the plants I knew I wanted. I decided to start my own plants from seed, not knowing that you normally would divide an older plant to make new plants. However, my seeds sprouted and grew. So, no problems there!
I decided to go for an older heirloom variety and choose “Glaskin’s perpetual”. This was first registered in England in the 1920. It has a low content of oxalic acid and can therefore be harvested later in the season too. When sown from seeds it takes a couple of years before the plants are established and large enough to harvest from.
Now, in the third year, I was expecting a very good harvest and large plants. However, I now notice that the plants are flowering. Normally, for a vegetable this often means the plant is no good for harvesting. So at first I was very disappointed! Then I did some research to learn more about flowering rhubarbs, and my mood improved.
It seems the stalks are still good for harvesting. Even if the plant flowers it does not have a negative effect on the taste of the stalks. It just means a significant smaller harvest as the plant puts most of its energy into producing the flowers and seeds. Observing my plants now, I see that this is correct – there are fewer stalks than last year.
It is perfectly normal for the plant to produce flowers, and under certain conditions, it just does. Some varieties are more prone to producing flowers; this is often the older, heirloom varieties. If the plant is stressed for some reason, either a too warm start to the year, or experiences pest damage, it is also more prone to producing flowers.
However, you don’t have to let the plant flower. As soon as you notice the flower stalk coming up, you can cut it off. That way the plant will produce more stalks and give a normal harvest, instead of going to flower and produce very few stalks.
For a few days, I was torn between letting the plant flower or cutting it back. In one way, I feel bad cutting the flower off, and it would be nice to see how the plant flowers too. If I don’t cut it, I won’t get a decent harvest. In the end, I decided to let one of the plant go to flower and cut the flowers off the rest of the plants.