This weekend I made two nice sirups from plants in my garden, spruce shoots and dandelion.
Both recipes are essentially the same. Collect spruce shoots or dandelion flowers (only the yellow petals), put in a pot, cover with water, boil for 30 minutes, pour mass through a sieve into another pot and weigh, add 2/3 of weight sugar, slowly boil to a slightly viscous consistency, and finally fill into bottles. For better durability, I boil the slightly opened bottles in a half full water-bath for about 30 minutes.