Common Name: Asparagus

General Information

Asparagus officinalis is a herbaceous, perennial plant with arching stems growing up from large underground rhizomes. It can grow up to 120cm tall[, ].
The plant is often cultivated on a commercial scale for its young shoots which are eaten in many countries of the world. The plant also has a wide range of traditional medicinal uses.

Known Hazards

Large quantities of the shoots can irritate the kidneys[, ]. The berries are mildly poisonous[].

Botanical References

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Range

Eurasia - Denmark to Spain, east to Ukraine and Greece, through western and central Asia to Afghanistan, western China and Mongolia; Northwest Africa

Habitat

Fertile and sandy soils by the seashore and along river banks[, ].

Properties

Edibility Rating
Medicinal Rating
Habit	Perennial
Height	1.00 m
Pollinators	Bees
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

Asparagus officinalis is a plant of mainly low elevations in the temperate zone, though it can also be cultivated at higher elevations from 1,000 metres up to 2,600 metres in the Tropics. It grows best in areas where annual daytime temperatures are within the range 15 - 30°c, but can tolerate 6 - 38°c[]. When dormant, the plant can survive temperatures down to about -15°c or lower, but young growth can be severely damaged at -1°c[]. It prefers a mean annual rainfall in the range 800 - 1,200mm, but tolerates 500 - 4,000mm[]. For healthy robust growth to take place, the plant requires a dormant period of 90 - 150 days when temperatures are low. It grows best when the days are hot but nights are noticeably cooler[].
The plant is easily grown in any good garden soil[], though it prefers a rich well-drained sandy loam and a sunny position[, , , ]. Prefers a pH of 6.5 or higher[], though it tolerates a pH in the range 4.5 to 8.2[]. Plants are very tolerant of flooding when dormant[].
Asparagus is often cultivated as a luxury vegetable, there are some named varieties[, ].
When grown from root divisions, the young shoots may be harvested 400 - 600 days from planting, and the harvest period generally last for 30 - 60 days. When grown from seed the plant may take an extra year before it comes into bearing[, ]. In cool periods, spears are harvested every two or four days but as days get warmer, daily harvest is often needed[].
Average yields of about 2.5 - 4 tonnes per hectare can be expected, whilst optimum yields can be up to 8 tonnes[].
Some farmers replant every 3 - 5 years but well-tended plants can be long-lived, an asparagus bed can remain productive for well over 20 years[].
A good bee plant[].
A dioecious species - both male and female forms must be grown if fruit and seed are required.

Edible Uses

Young shoots - raw, cooked or pickled[, , , , 27,418, K]. Considered a gourmet food[], the shoots are harvested in the spring. We find them very acceptable raw in salads, with a hint of onion in their flavour[]. They are normally boiled or steamed and used as a vegetable[]. Male plants produce the best shoots[]. Do not over-harvest the plant because this would weaken it in the following year. The shoots are a good source of protein and dietary fibre[].

Roasted seeds are a coffee substitute[, , ].

Medicinal

Asparagus has been cultivated for over 2,000 years as a vegetable and medicinal herb[]. Both the roots and the shoots can be used medicinally, they have a restorative and cleansing effect on the bowels, kidneys and liver[].

The plant is antispasmodic, aperient, cardiac, demulcent, diaphoretic, diuretic, sedative and tonic[, , , , ]. The freshly expressed juice is used[].

The root is diaphoretic, strongly diuretic and laxative[, , ]. An infusion is used in the treatment of jaundice and congestive torpor of the liver[]. The strongly diuretic action of the roots make it useful in the treatment of a variety of urinary problems including cystitis[]. It is also used in the treatment of cancer[]. The roots are said to be able to lower blood pressure[, ].
The roots are harvested in late spring, after the shoots have been cut as a food crop, and are dried for later use[].

The seeds possess antibiotic activity[]. Another report says that the plant contains asparagusic acid which is nematocidal and is used in the treatment of schistosomiasis[].

Agroforestry Uses:

Asparagus is a good companion plant for tomatoes, parsley and basil[, , ]. When grown together, tomatoes help to protect asparagus from the asparagus beetle[]. Asparagus is said to repel the nematodes that can infect tomatoes[] (see the report below on the plants other uses).

Other Uses

The plant contains asparagusic acid, which has nematocidal properties[].

Propagation

Seed - pre-soak for 12 hours in warm water and then sow in spring or as soon as the seed is ripe in early autumn in a greenhouse. It usually germinates in 3 - 6 weeks at 25°c[]. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in a sunny position in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer[].
Division in early spring as the plant comes into growth.