"I must sow poppies in my garden," sighed Dorian.
"There is no necessity," rejoined his companion. "Life has always poppies in her hands."

– Oscar Wilde

The Picture of Dorian Gray, Chapter 8. When Dorian says this he doesn’t mean he is literally going to sow poppies in his garden. This is a metaphor meaning that he is going to mourn the death of Sibyl Vane, poppies being a symbol of remembrance and the garden signifying life. Lord Henry tells him that there is no need to mourn, that life will continue to produce occasions of mourning – this is foreshadowing of further deaths to come.