Since Sept & Oct are hot months in my zone 9 N. CA area, when should I plant irises?

Question

Bulb companies send out fall bulbs in Sept.and advise you to plant as soon as you get them. Sept & Oct are often in the 90’s,occasionally even 100 degrees. though it does cool down below 60 degrees at night. Should I wait for cooler weather before I plant irises?

Answer 1

Iris should be planted at least 6 weeks before the first frost to perform well in spring. You could probably plant iris in September or October, even if it's still warm. In cooler zones, iris are planted in late summer.

https://www.gardeningknowhow.com/ornamental/bulbs/iris/iris-plant-care.htm