Clean and trim rhubarb and dice into 1/4" pieces. Note, depending on the amount that you need to trim away from the stalk, you may need to harvest or purchase more that two pounds in order to have a full two pounds for this recipe.
Thoroughly wash 2 medium oranges. Cut off a small portion of the stem and blossom ends, then quarter the remaining orange, removing seeds. Place orange quarters into a food processor and process until orange is resembles a fine meal.
In a large heavy bottomed pot, combine rhubarb, orange, sugar, water and lemon juice. Over medium heat, bring the mixture to a simmer, stirring frequently. Continue to simmer and stir until the mixtures thickens to a jam like consistency. It should coat the back of a spoon when properly reduced.
Ladle into sterilized half pint jars leaving a 1/2" head space, wipe the rims clean, and twist on prepared lids and rings finger tight.
Process in a water bath canner at a rolling boil for 10 minutes with at least one inch of water covering the lids of the jars.
After processing, remove from canner and allow to rest until completely cool. Ensure that all seals have set and loosen or remove rings for storage.