When asked for my opinion on an easy plant to grow, Rhubarb is always at the top of my list. When asked about interesting plants, I volunteer Rhubarb. And when asked about foolproof plants for new gardeners, Rhubarb springs to my tongue.
Rhubarb can give you two harvests a year. Because low temperatures stimulate growth, you'll get the initial foliage burst in early spring and good stalks to harvest in late spring. The heat of summer will suppress cellular activity, but when temperatures begin to cool in fall you will see the foliage begin to grow again. You can often harvest stalks just before the first snows fall.
Of course, because it excels as a cool season plant, Rhubarb may not do well in very hot gardens. It can survive in excessively hot and dry regions, but will only produce thin stalks with very little color. If you have four seasons, or at least a long period where temperatures are below freezing, Rhubarb should do well in your garden.
Rhubarb will grow in just about any soil though it prefers well-drained soils with lots of organic matter. It can also handle a wide range of soil pH, but does best when it's slightly acidic; my soil is alkaline and I've never had a problem. I recommend amending the soil well before you first plant and then mulching with partially-decomposed compost. Adding a balanced fertilizer when growth begins in the spring will benefit the plant but isn't always necessary if your soil is amended.
Rhubarb is best grown from dormant crowns and roots that you can purchase at nurseries, garden centers, or online. Plant the crown just below the soil surface in early spring to get the best start. Rhubarb plants can get quite large so allow space when planting, as much as four feet between crowns. Remember that it is a perennial plant that will come back every year for as long as 15 years, so choose its location carefully and wisely.
You can try growing from seed but it takes longer for the plants to establish. I do pot up seedlings from the established plants that I let go to seed. Be aware that the seedlings from hybrid cultivars will not be true to the parent plant. I've had great success with "Victoria", a sweeter variety that isn't as red as other Rhubarb, but that does well from seed.
During the first year, water well, remove the round, tall flower stalks when they appear, and do not harvest any of the stalks. You want a maximum amount of the plant's energy going into root development. In subsequent years the plant will require much less water and care. In the second year, minimize your harvest to encourage strong development, but by the third year and every year after you can harvest every stalk if you choose, but I don't recommend taking more than half of the plant.
Depending on how you use it, you can harvest a few stalks at a time or harvest the entire plant. You can pull out the stalks individually or cut them at the soil line. For at least a month, you'll be able to select stalks for harvest. Only the stalk is edible so throw the leaves in your compost pile.
I leave a number of stalks with leaves on the plant at the end of the season. When the cold of winter comes and the leaves dry out, I use them as a mulch to help protect the crown through the most severe cold. Rhubarb can easily handle -20F degrees of a zone 5 garden. My plants have survived -30F with the mulch protection of the dried leaves. Straw or other autumn leaves will work too.
After the Rhubarb is established it can handle just about any challenge including drought. Even if you stop watering and fertilizing, it will keep producing, though not as well as when you give it proper care. I've had seedlings that I potted and forgot about. Six months later, after sitting abandoned in a field during the cold winter with no watering, the plants sprang to life in early spring.
There are very few pests and diseases that affect Rhubarb. You can let it grow strong with very few worries. About the only thing to concern yourself with is overwatering. A young crown may rot if it is covered with too much soil or if it is saturated too much, but even that is unlikely. Remember that an established plant can handle drought, so don't try to pamper it with too much water.