When selecting your plums, use either the purple plums that are deep-colored or golden plums. Both should be of good quality, fruit that you would use for eating fresh. I used golden plums as they were available here at our local market.
The first step is to stem and wash your plums. To can them whole, prick the skins on both sides of the plums with a fork to prevent splitting. Freestone varieties may be halved and pitted. The golden plums I used were freestone so were easy to remove plus you can pack more plums into a jar if they are halved.
I use a light syrup for canning my fruit. Light syrup is a ratio recipe. 1/2 cup of sugar dissolved in 1 cup boiling water. To prevent browning of the fruit use 1/2 teaspoon of lemon juice per jar.
In a medium pot bring the sugar mixture to a boil with the fruit. Boil one minute. In the meantime, add a half inch piece of a cinnamon stick and a half inch piece of vanilla bean pod to the bottom of the sterilized jars. You can leave these out if you prefer to just have plain plums.
Pack fruit as tightly as possible without bruising the flesh in sterilized jars.With a ladle pour syrup into jars to cover fruit leaving 1/4 inch head space. Screw on lids to finger tightness and water can for 10 minutes.
Remove from water canner and allow to cool. Wipe jars clean, label and store.