There are so many ideas for making your own Jesse Tree online - lots of versions of felt ornaments along with collections of different items for ornaments. But if you want something quite quick and easy, there are also printable ornaments.
You can print off sheets with all the ornaments either in colour or for the kids to colour in. These can be glued onto a picture of a tree or onto small pieces of card with a string attached for hanging to a tree. Here is the link to one version Printable Jesse Tree Ornaments
This is a nice idea. Print off small pictures to represent the Jesse Tree readings, and glue them to flat glass "marbles". Add magnets to the back and you have a set of magnetic Jesse Tree decorations. Instructions and printable for this can be downloaded here.