Plums are great for jam. They have enough pectin to thicken a jam and enough acidity to provide a nice balance for all the sugar that preserves the fruit. The only two ingredients in the jam above are plums and sugar. The plums are from an Italian Prune Plum I have in the yard. I had about 4 cups of chopped plums and added 3 cups of cane sugar. I boiled and occasionally stirred for about 20 minutes and it was ready for the jar.
The yield was only about a pint and a third. With that small amount, I just refrigerated the jam. If I made a larger quantity I would do a hot water bath so it would be shelf stable outside of the fridge. Consuming a bit over a pint before it goes bad in the fridge won’t be a problem. Sugar is a good preservative.
The Italian Prune Plum is a versatile fruit. In dry climates (not here in the humid southeast) the fruit that isn’t picked and eaten fresh hangs on the tree and dries into prunes. I have used a dehydrator other years when I had more. The tree is self fruitful so only one is needed. It is also disease resistant.
The biggest challenge in this area is the plum curculio. It is a fruit worm that has a taste for peaches and apples as well as plums. Controlling it organically requires more diligence than I provide. Spraying with kaolin clay is effective if the treatment begins when the blossoms fall and is consistently applied after every rain. Since I didn’t try to keep that barrier in place, most of my plums have worms. I cut around the worm damage when preparing the jam. The plum curculio prefers softer fruit so my tree likely lessons the worms that I find in my apples and pears.
My plum tree is 13 years old. Fruit trees have a shorter life expectancy in the southeast than less hot and humid places. I’d like to make sure I have one of these around so I cleaned and saved pits.
These are now in a bag in the fridge with some moist potting soil. Italian Prune plums grow well on their own roots. Next spring I’ll see if some of these sprout. I may have enough to barter with or possibly a guerrilla gardening venture.