Depending on which region you are in, you can plant it now in the north, or earlier in the south. If it is for ornamental use, it depends on when you want it to bloom. The flowering period is from June to September. Early planting means early flowering. If there are special needs, it is recommended to plant the seedlings in advance and transplant them, or plant them in the autumn of the previous year so that they will germinate early in the spring.