Florence Fennel, a native of Italy, is sometimes known by its Italian name finnochio and seen in markets labeled (although inaccurately) sweet anise. It's a perennial vegetable plant in most zones that actually provides one vegetable, an herb and two spices. Foeniculum vulgare Azoricum as a vegetable uses the plant's spreading bulbous base, with a texture much like celery, but with a subtle anise flavor that
Fennel has become naturalized along roadsides, in pastures, and in other open sites in Northern California, with plants growing several feet high with clusters of yellow, umbrella-shaped flowers—similar in look to Yarrow. This is plain Foeniculum vulgare, the fennel that is deemed 'invasive' in the Bay Area. Florence fennel plants, on the other hand, have broader leaf-bases, or bulbs, which comprise the vegetable portion of the plant. There are several cultivars of Florence: Zefa Fino matures in just 65 days, and produces the highest weight bulbs of firm, white highly aromatic flesh; Trieste, another excellent choice matures in 90 days.
Fennel is easy to grow, and best propagates by seed. The taproots of the plant don't transplant particularly well, and any disturbance of the root can tend to cause the plant to bolt. The best time to plant Florence fennel is either in early spring or in July through early August so that the plants can mature in cooler fall weather. Spring-sown plants are more likely to bolt so many gardeners will wait until July/August to seed their fennel and harvest the bulbs in the fall. Florence Fennel plants may be placed close together, the seedlings only 4-6 inches apart, in rows 18" apart. Plant the fennel seeds in full sun directly into rich soil, and keep the bed moist for two weeks until the first leaves appear. They are very thirsty and require watering frequently in dry weather. At 2" tall, thin every other one, to 8-12" apart. At this point however, be careful not to over water. Feed them at least once before maturity. Fennel can be planted right up through August.
When the bulbs are about the size of an egg, you can, if you choose, pile the soil up around them so that they will continue to grow away from the light, remaining white. At this point the bulb is 2 to 3 weeks from harvest. You may harvest the seed heads when they form and give the bulb a few more days to grow, then harvest it. The plant is not particularly frost-tender, and in mild climates you can grow and harvest fennel all year long. It is in flower from August to October, and the seeds ripen from September to October. Allow one plant to go to seed and it will re-seed your garden for a few years.
Fennel attracts many beneficial insects: bees, hoverflies, ladybugs, lacewings, and syrphid flies will often be found hovering around the flowers or laying their eggs in the foliage. Bronze fennel is the preferred host plant for swallowtail butterflies. If you plant some near your roses it will definitely help to keep the aphids at bay.
The bulb, feathery frond, seeds and pollen of fennel are broadly used in many culinary traditions around the world. Fennel pollen is the most potent form of fennel, and is exceedingly expensive if purchased commercially, but easy to harvest from the garden, or even from local roadsides: tie the heads in a brown paper bag, and hang with string upside down in the garage rafters, or in your pantry or cellar until dried. Strip the pollen from the heads, and store in an airtight spice jar. Dried fennel seeds are an aromatic, anise-flavored spice which are brown or green in color when fresh, and slowly turn a dull grey as the seed ages. For cooking, fresher seeds are optimal. Fennel seeds are sometimes confused with aniseed, which is very similar in taste and appearance, though smaller. In India, it is common to chew sugar-coated fennel seed after dinner as a mouth-freshener.
Many cuisines in the Middle East, South America and on the Indian subcontinent utilize fennel seed. It is a key ingredient in Italian sausages and northern European breads such as Swedish rye. It is an essential constituent in Chinese five-spice powder, Indian garam masala and the Bengali/Oriya spice mixture panch phoron. It is known as saunf in Hindi and mouri in Bengali.