Cool weather crop.

The broccoli plant,  is a Brassica, and is a member of the cabbage family which includes other cruciferous vegetables like cauliflower, kale, bok choy, and Brussels sprouts.

Broccoli stems and heads are both edible. The heads are essentially flower buds; allowed to mature they will open into tiny yellow blossoms., Flowers are great pollinators and are also edible or used to dress up a salads. Many varieties can be grown that allow for harvest of the main head and then additional smaller headed shoots grow out and can be harvested. This make a broccoli plant more useful in a limited space garden like a raised bed as it will produce more than one cutting. (cut and come again)

The two main types: sprouting and heading. Sprouting broccoli has long, slender stems that can be prepared and eaten like asparagus. Heading, with its large crowns of tightly packed florets.

You can grow broccoli outdoors in the spring for early summer harvest or plant late Summer to Fall for a Fall thru Winter harvesting. There are verities of Asian leafing broccoli that are grown for the leaf or small flowering head. These are less common in Western gardens but do grow well in our mild Winters here in N. Texas. Look for Chinese broccoli in your seed catalogs to gain the broccoli flavor and health benefits but a more space saving garden green.
Just a half cup of broccoli contains 70% of your daily vitamin C requirement. Broccoli also contains high amounts of vitamin K1 (important for blood and bone health) and folate (essential for tissue growth and cell function), plus potassium, fiber, calcium, and large amounts of antioxidants.