Harvest & wash wild plums. For a firm jelly, be sure to harvest both juicy-sweet perfectly ripe as well as slightly unripe plums to get the most natural pectin.

Place washed plums into a large stockpot and add just enough water to cover. Bring water to a simmer and cook fruit until softened, mashing with a potato masher. (about 10-15 minutes)

Line a colander with a jelly bag or cheesecloth and place atop a deep pan. Dump softened mashed plums into the colander & place in the fridge overnight to fully strain the juice.

The next morning measure strained juice and add 3/4 cup granulated sugar for each cup of juice. Stir together in a large stock pot.

Simmer juice over medium-high heat stirring frequently until juice reaches 220 degrees (at sea level) This takes me about 15-20 minutes.

If desired, ladle into sanitized jars leaving 1/4" head space. Seal in a water-bath canner for 5 minutes. Remove sealed jars & place them in a draft-free location for 24 hours before removing rings and testing for seal.