Wash kudzu blossoms with cold water. Put in bowl. Pour 4 C. boiling water over blossoms and refrigerate 8 hours or overnight.
Pour blossoms and liquid through a colander into a dutch oven, discarding blossoms. Add lemon juice and pectin, bring to a full rolling boil, stirring constantly.
Stir in sugar, return to full rolling boil and boil, stirring constantly, for 1 minute. Remove from heat, skim off foam.
Quickly pour jelly into hot, sterile jars, filling up to 1/4" from top. Wipe jar rims. Cover at once with metal lids and screw on bands.
Process in boiling water bath 5 minutes Cool on on wire racks. Makes 6 half pints
NOTE: Blossom liquid is gray until lemon juice is added.