Avoid plant food on the rhizome when you plant. Nitrogen can hurt the rhizome. The American iris society has an excellent web page to show you how to plant your irises. Make sure you have a sunny spot that is well drained.
Ideally you could plant both flowers and vegetables in your garden but if you want to keep them separated is your choice.
Unlikely, but you can force bloom the plant by placing it in the refrigerator for a few weeks and then replanting it outside again. This can force it to rebloom but also can tax the plant to death.
It should be the flowers
Pollen from flowers on one plant can fertilize flowers on a different plant. What is this process called?'
Flowers produce seeds for the plant
Most gardeners plant in the spring. However bulbs and iris are best planted in fall.
You should recycle and plant some flowers for the hummingbirds and bees.
You should shape the plant in May and pinch back flowers.
The flowers, leaves, and root. Leaves should be harvested before the herb blooms, leaving at least two thirds of the foliage on the plant. The flowers should be harvested just as they open. And more . . .
It is not up to the plants when to or not to produce flowers. It depends on how healthy the plant is after fertilisation. The healthier the plant is, the faster it will produce flowers.
If hunger is a prime factor, then yes.
The time you plant flowers depends on the type of flowers you are planting. An almanac can help you determine the best times to plant anything.