Pollinator Friendly Plants
In order to have healthy bee colonies and subsequently healthy honey harvests, its important that bees have sufficient sources of nectar to forage from. Pollen is required as well but typically there are sufficient sources of pollen in the Chicago area throughout the year that we won't be focusing on sources of pollen but rather plants that are native to North America and major sources of nectar. Bee friendly nectar sources for Chicago can be broken down into two separate categories.
Trees - This is number one for a reason, bees in the Chicago region source a majority of their nectar from trees. Trees have deep roots and can provide a source of nectar even in dry years. Whenever someone asks "what should I plant for the bees?" I always answer with "A tree if you can"
Plants - Everyone loves flowers but most garden shop flowers are largely useless to bees. Prairie or woodland plants typically are much more suited not only to honey bees but to other pollinators as well such as solitary bees and bumblebees. The Illinois DNR maintains excellent resources for native plants and tips/tricks for starting a pollinator garden.
As mentioned, trees are incredibly important nectar sources for bees however a lot of trees bloom too early for bees to effectively forage from them. Chicago is either in USDA Hardiness Zone 5b or 6a depending whether you are in a collar city or in Chicago proper. Trees like Maple provide excellent sources of nectar but bloom too early in April. Bees need air temperatures well into the 50s for effective foraging.
Plants (Full to Mostly Full Sun)
Illinois is the native home of many species of plants that not only are beautiful but provide good nectar sources to bees.
Plants (Part Sun to Full Shade)
These plants should be considered woodland plants. Have a bungalow that is well shaded by a big tree. These plants might be perfect for you.