Fennel is a beautiful, aromatic herb with a mild licorice flavor. Both bulb and herb types are worth growing.
Zone 4A has a short growing season — start seeds indoors when possible and use season-extending techniques like cold frames and row covers.
Good companions: dill (same family, attracts same beneficials)
Avoid planting near: most vegetables — fennel is somewhat allelopathic (inhibits nearby plants). Grow separately.
Bulb: 65-90 days from seed; herb leaves anytime
USDA Hardiness Zone 4A has an average last spring frost around May 8 and first fall frost around Sep 25. All planting dates above are calculated from these frost dates. Your specific location may vary — check with your local extension office for the most accurate dates.