Asparagus officinalis (Asparagus)

Prized for its delicious young shoots or spears, Asparagus (Asparagus officinalis) is a long-lived perennial with tall, graceful, feathery foliage that is highly ornamental. Widely cultivated as a vegetable crop, the tender young shoots are one of the first vegetables ready to harvest in spring.

• Asparagus is native to Europe, Asia, and northern Africa and naturalized in temperate regions worldwide.
• Cold-hardy (zones 2-9), Asparagus thrives in areas with winter ground freezes or a dry season to provide a dormant period each year. Frost pockets should be avoided as Asparagus spears are tender.
• Only young Asparagus spears are commonly eaten: once the buds open, the shoots quickly turn woody.
• If spears are left to grow, they develop leaves (ferns). Asparagus harvest is only a few weeks instead of the entire season because the plants need the ferns to grow to build up energy for the following year.
• Asparagus shoots are prepared and served in many ways worldwide, usually as an appetizer or vegetable side dish. In Asian-style cooking, Asparagus is often stir-fried. It may also be quickly grilled or used as an ingredient in stews and soups.
• Asparagus can be started from seed or one-year-old roots (crowns).

Choosing Asparagus 

• Asparagus is dioecious: there are female plants and male plants. All produce edible spears. 
• Female plants grow larger spears.
• Male plants tend to live longer and produce more spears.
• Asparagus plants with all female flowers produce red, inedible berries in summer.
• Plants with all male flowers do not use energy to develop seeds and fruits.
• Female plants can produce weedy seedling asparagus plants.
• Most Asparagus hybrids, such as Jersey Giant, are plants with only male flowers that produce no seeds.

White, Green, and Purple Asparagus 

• White Asparagus is a delicacy that is popular in Europe and western Asia. White Asparagus is not a particular variety. It results from applying a blanching technique while the asparagus shoots are growing. The shoots are covered with soil as they grow without exposure to sunlight. Since there is no photosynthesis, the shoots remain white. White Asparagus is slightly sweeter than green Asparagus.
   
• Green Asparagus is a bit grassy and nutty in flavor and richer in fiber, calories, protein, fat, carbohydrates, iron, and calcium.
   
• Purple Asparagus was originally developed in Italy. Purple Asparagus differs from its green and white cousins in having high sugar and low fiber levels. Purple Asparagus can turn green while being cooked.

Asparagus Health Benefits 

• While Asparagus makes a flavorful addition to many dishes, it can also provide some health benefits.
• Asparagus contains vitamins (A, B, C, K, E), minerals (calcium, magnesium, and zinc), fiber, and antioxidants.
• Asparagus can help prevent eye diseases (cataracts or macular degeneration), regulate cholesterol, lower blood pressure, fight free radicals, and improve digestion.
• Asparagus is also a rich source of folic acid that helps prevent anemia, tingling hands and feet, and even birth defects.

Growing Asparagus

• Asparagus grows up to 3-5 ft. tall (90-150 cm) and 1-3 ft. wide (30-90 cm).
• Asparagus performs best in neutral to slightly acidic (pH of about 6.5), moist but well-drained soil in full sun. Asparagus is salt tolerant and suitable for coastal areas.
• Dig out all weeds and add plenty of compost to the soil before planting.
• Newly-planted asparagus plants may take 2 years ( after planting crowns) or 3 years (after planting seeds) to produce their delicately-flavored spears, so be patient!
• Select a permanent location carefully since asparagus plants will produce for 20 years or more.
• Plant in edible or vegetable gardens, along borders for mass planting, or in small groups. If your soil is heavy or poorly drained, plant asparagus in raised beds.
• Asparagus requires high levels of phosphorus, potassium, and nitrogen. Consider using an organic fertilizer during the growing season.
• Mulch to retain moisture and control weeds.
• Cut down foliage in fall, when yellowed, to 1 in. (2.5 cm) above the soil.
• Asparagus are susceptible to asparagus beetle, spotted asparagus beetle, aphids, fusarium, rust, and needle blight. 
• Asparagus are rabbit-resistant.
• Wearing gloves is recommended for handling young shoots, as contact dermatitis is likely.
• Propagate by seed or by division.

Asparagus Companion Planting

• Excellent companion plants for Asparagus are dill, coriander, basil, comfrey, marigolds, parsley, tomatoes, strawberries, thyme, oregano, and alyssum.