The edible part of the asparagus is the young, fast growing shoots or spears. Female plants produce berries - these immature green berries ripen to red when mature.
Garden asparagus is an erect herbaceous perennial that emerges with several stems in early spring from a tuberous, matted rootstock. The much branched stems and branchlets are ringed with clusters of thin, hairlike structures called cladophylls, giving the plant an overall feathery appearance. The true leaves (if you can find them at all) are tiny and scalelike, and are best observed on the newly emerging shoots. Asparagus usually grows 3-5 ft (1-1.5 m) tall. Small drooping flowers in clusters of 1-4 appear in late spring. Female plants produce bright red berries in summer. Several cultivated varieties of asparagus have been derived from the original wild plants. The old standard, 'Mary Washington', is still a popular cultivar for the home garden, but there are some newer ones that may be better suited for specific climates and soil types. Male plants are preferred because they spend the growing season developing strong root crowns for next season's spring flush, rather than expending energy on fruit development.
Location Asparagus officinalis hails from coastal areas of the eastern Mediterranean region in Europe, Asia and North Africa. Asparagus has escaped from cultivation in many areas and can be found growing wild in waste places.
Since asparagus is a perennial, it should not be disturbed once established. Regular weeding and fertilizing will be required. Light: Asparagus, unlike most garden vegetables, can tolerate partial shade. In cool climates, full sun is best. Moisture: Regular watering insures good growth. Hardiness: USDA Zones 4-8. The best quality asparagus is harvested when night temperatures are in the mid 60's F (around 18 C), and daytime highs are in the 80's F (around 29 C). Moderate summer temperatures allow the plants to develop strong crowns which will give birth to next spring's shoots. Asparagus must go dormant in the winter and will not produce good crops in mild winter climates. I have had a patch of asparagus in my Zone 8B garden for more than 15 years and it has never produced enough spears to make a serving. The summers are just too hot and humid, and the winters too mild. Propagation: Asparagus for the home garden and for commercial fields is usually propagated from root crowns which were grown from seed in commercial asparagus nurseries. The crowns are more than a year old when planted out about 18 in (45 cm) apart in rows about 5 ft ( 1.5 m) apart. Set the crowns in furrows 6-8 in (15-20 cm) deep and cover with 2-3 in (5-7.5 cm) of soil. As the plants grow, gradually fill in the furrows. New asparagus plantings should be allowed to become well established for a couple years before harvesting. You will need 10-20 plants per person.
In summer, the asparagus patch is a cloud of feathery green foliage.
Garden asparagus is grown for the delicious shoots that emerge from the root crowns in spring. These are harvested by cutting off the spears at or slightly below ground level. The harvest period can extend for several weeks, but must eventually be halted to allow the plants to grow during the summer and store carbohydrates for next year's crop. Take only spears that are thicker than a pencil and stop harvesting when most are thinner than that. Asparagus is sometimes blanched by piling soil or mulch over the shoots and cutting them off below grade when the tips first appear. The frilly foliage is fine for formal flower arrangements.
There are abut 300 species in the lily family genus Asparagus. These include herbaceous perennials, woody vines and even shrubs, but all share the feathery look with their green branchlets and frilly cladophyls. Several species are grown as ornamentals, including one called asparagus fern (A. densiflorus).