Orchid

at level 7 in gardening to graft the orchid to another plant click on the other plant orchid + pomegranate = death flower

other than that you can graft an orchid with any other plant for example  orchid  and  strawberry plant and the strawberry plant will grow both but to actually plant a better orchid you need to plant the flower from your inventory from the plants your sims harvests

edit drag the flower from the inventory to the ground click on it plant