This bug has been fixed in patch 1.0.732.20
Tulip and Chrysanthemum is also reported by Carl as not working ( http://www.carls-sims-4-guide.com/skills/gardening/ )
and I put elsewhere (misc bugs) that sage + basil don't splice.
It's proposed by "folks "at this point that the splices/graft combos that do not work are those that do in fact produce the plants that cannot be found in seed packets OR in the wild from harvesting/cutting + grafting and that they have to fix this in a patch.
And while we're talking about plants in general from gardening, plantain is not on the list for plant collection apparently.
the one thing i did notice with those plants as i just grafted a daisy and strawberry is the grafted plant did not shrink down in size other plants where the grafting does take the plant shrinks in size to grow in it's newly formed graft condition
edit to add the graft counts in the sims aspirations count (graft 0/10 i was on 6/10) with the graft i just did daisy and strawberry it counted in 7/10
