In ancient Japan, during the Heian era (approx. 794 to 1185), it was believed that ayame 菖蒲 -- iris flowers -- could ward off evil spirits and bring good luck, and their sweet fragrance was said to purify the air.
In fact, a whole festival day was dedicated to the iris flower; ayame no sekku 菖蒲 の 節句 (also called tango no sekku 端午の節句) was celebrated on the fifth day of the fifth (lunar) month. The Imperial Palace and private homes were decorated with the flowers, and the plant itself, along with mugwort leaves, were strewn upon roofs. A special banquet was held where the Emperor shared sake steeped with iris petals amongst his courtiers. Iris kusudama 薬玉 -- small bags containing medicinal herbs, decorated with brightly coloured threads and flowers -- were hung in rooms and beneath eaves.
So...just maybe...an iris here on this webpage will drive away the bad luck it seems to have accumulated over the years.