By Lois Scott, Master Gardener
It is early May and my husband has been watching the rhubarb emerging with great anticipation. I like rhubarb, he loves rhubarb and it will soon be time to start harvesting the stalks (petioles)!
Rhubarb (Rheum rhabarbarum), native to central Asia,is an easy, hardy, and edible perennial. Technically a vegetable but treated as a fruit, it is long-lived, easy to care for and bothered by few pests and diseases.
Rhubarb is sold by ‘crowns’ or perhaps you can get a division of a plant from another gardener. Spring and early fall are the best times to plant it. Rhubarb likes a well-drained site with full sun (6-8 hours minimum). Give your plant plenty of space to grow, about 3m2. Rhubarb is a heavy feeder so mulch around your new or established plant with compost or well-rotted manure. I generally give mine a spring dressing of compost as it starts to emerge in the spring. Rhubarb should be watered deeply during times of drought.
A new rhubarb plant will need a couple of years to get established before you start harvesting it. Don’t harvest any stalks the first year and then very little the second year. The plant needs those large leaves to develop to provide energy for the roots and crown to grow. Over the growing season, flower stalks will start appearing and these should be cut off at the base to reserve energy for the plant.
Rhubarb is ready to harvest when the stalks are 25 – 40 cm long. Grab the stalk part way down and pull or twist to the side. When I pull rhubarb, I come prepared with a paring knife and cut off the leaves after pulling the stalks and leave them as mulch. Rhubarb leaves are toxic as they have high levels of oxalic acid, however they can be safely composted.
Rhubarb is a cool weather plant so as the season warms up growth may slow down. Let your plant rest so the crown can recover. If you have an established plant that doesn’t seem to be as vigorous as it was, it may need division which should be done in early spring. Dig up the whole plant if possible. Rhubarb has a very deep tap root but if you capture enough, you can divide the plant making sure each division as at least one or two buds. Plant your divisions with the buds 4 – 5cm deep, gently firming the soil.
The only other job to do is weed through all the tempting rhubarb recipes. Enjoy!