Daily Halacha - Shabbat Laws, 10th of Av 5777

Is it permissible to place flowers in a vase filled with water on Shabbat?

It is permissible on Shabbat, even initially, to place aromatic woods and myrtle branches in a vase containing water, and it is also permitted to add water to the vase and then place the myrtles and aromatics inside it.

However, flowers and roses whose buds are closed and may open in water should not ideally be placed on Shabbat in a vase containing water, and even if they were removed to smell them, they should not be returned to it. But if the roses and flowers are already open, it is permissible to place them on Shabbat in a vase containing water. One who is stringent with roses even when they are open will be blessed [Yechaveh Da'at 2, 53].

Ach Tov VaChesed - Daily Halacha