Prepare the lime water solution by mixing the lime and water. Allow the mixture to settle, then carefully use only the clear liquid portion.
Wash, peel, and pit the plums, keeping them as intact as possible.
Place the plums in the clear lime water solution and soak for 1 hour.
Remove the plums and rinse thoroughly several times under fresh water.
In a large pot, combine the sugar and 1-2 cups of water. Cook over low heat until the sugar dissolves and forms a thick syrup.
Add the lemon juice, lemon slices, vanilla, and diluted citric acid to the syrup.
Carefully add the plums and simmer gently for about 25 minutes until the fruit is tender and glossy.
Add the rose leaves during the final few minutes of cooking, if using.
Remove from the heat and allow the slatko to cool completely.
Transfer the plums and syrup to sterilized jars and seal tightly.