We inherited a rhubarb patch when we moved into our current house two years ago. I love Rhubarb in both desserts and main courses, particularly with fish (not with dessert). It's July right now in Ireland and some of my Rhubarb is ready for cutting. The indicators are that the stalks are long, thick and reddish green. Last year, we were able to get three harvests in one season, so the earlier the better.
I'm going to describe here how to freeze it and also my experiences with growing and transplanting it. All you need to start off is a pair of garden scissors and a resealable freezer bag, and of course, Rhubarb and a freezer. I'll stop there on the assumption that electricity and water can be taken as a given.
Step 1: Harvesting the Rhubarb
I have a patch with 7 mature plants. The rules I follow are that I cut the largest stalks first and after taking one stalk from one plant, move on to the next plant. One freezer bag can hold about 5 medium stalks. Cut the stalk close to the base clump, then cut off the leaf, ensuring that there is no leaf residue. THE RHUBARB LEAF IS TOXIC so please ensure that you don't use it. The poisonous element of Rhubarb leaves is Oxalic Acid which is present in high concentrations. Most plants contain Oxalic Acid but not as high a concentration as rhubarb leaves. The Rhubarb stalk is safe to eat but is always cooked. You should use the leaves as a mulch to suppress weeds.
(As an aside, I worked in the brewing industry, and one challenge was to remove Oxalic acid from the malted barley during the boiling stage. The problem was that if the pH was too high then the Oxalic acid, in the form of Calcium Oxalate, would remain in the beer liquid. The problem then was that it would form a bloom or suspension in the finished product. I once had to return a bottle of Scotch Whiskey because it had an Oxalate Bloom)
Step 2: Cutting and Freezing the Rhubarb
Wash the Rhubarb stalks and then dry before cutting into one inch lengths. Next place into the resealable freezer bags and mark on it the date of harvest, before placing in the freezer. Some people recommending blanching (placing the stalks in boiling water for 60 to 90 seconds) but in my opinion this introduces the risk of pre-cooking. Another tip is to minimize the time between harvest and freezing, and ensure that you have enough Rhubarb to fill the freezer bag, and vice-versa.
From experience, the Rhubarb is good for up to 9 months in the freezer. When using it from the freeze, I let it thaw at room temperature in the kitchen.
Step 3: Transplanting and Cooking Rhubarb
I had to transplant some Rhubarb this Spring (when the plant was dormant ) because the roots were lifting my paving stones. Mature rhubarb creates enormous roots so be careful with them close to a house. Amazingly, after removing a large section of the root, the plant survived. I took a Rhubarb crown from this plant and removed two sections which each had a growing point / bud. I planted one in a sunny spot in soil which I had fertilised with seaweed and another to a partially shaded area, again with similar soil. I turned the soil, ensuring that it was sufficiently crumbly to permit the Rhubarb roots to develop. For three months, March to July, it looked like the clumps had died but a few weeks ago , they sprang into life - see photos.
Some Ideas for Rhubarb
Rhubarb jam and even wine are quite well known. One of my favourite recipes for Rhubarb is to make a puree to accompany fish, particularly Mackerel. Take half a Rhubarb stalk in one inch sections and gently saute for 1-2 minutes. Turn off the heat and sprinkle some Tumeric over the pulp then add one teaspoon of honey for sweetness. Remove the water and serve immediately.