Common Name: Asparagus
Scientific Name: Asparagus officinalis
Family: Asparagaceae (the Asparagus family)
Asparagus is another one of those vegetables people either love or hate. I absolutely love fresh Asparagus and believe that they are one of the most delicious vegetables created. They can be green, purple, or white. These are the best known perennial vegetable, and can produce shoots every Spring for over 20 years. The “ferns” are quite beautiful and used as ornamentals, and the flowers attract beneficial insects. One of the best tasting vegetables for the Forest Garden.
Native to Eurasia, Asparagus has been cultivated for over 2,000 years. It was used in ancient Egypt, Syria, Spain, Greece, and Italy. It was cultivated in France in the 1400’s and England and Germany by the 1500’s. It wasn’t until the mid 1800’s that it was cultivated in North America.
- There are over 300 species in the Asparagus genus.
- Most Asparagus species are grown as ornamentals, but there are a number of edible species. These are not well known except by locals.
- Most Asparagus plants are either male or female.
- Male plants produce the best shoots.
- Female plants produce hard red berries that can easily spread new plants all over the place – one reason most growers do not grow female plants.
- Often grown as a companion plant to tomatoes as the tomato repels the Asparagus Beetle (Crioceris species), and the asparagus may repel nematodes.
- Asparagus shoots are typically green, but purple varieties have been developed.
- White Asparagus is not a variety – any shoot can be blanched by covering with mulch, soil, dark buckets, or black plastic tarp tunnels. White Asparagus is less bitter and more tender than green Asparagus.
- When Asparagus is digested, certain compounds found in the shoot are metabolized and excreted in the urine. These compounds have a strong smell which gives urine a distinctive post-Asparagus-eating odor. The compounds can be found in the urine in as little as 15 minutes after ingesting the vegetable.
USING THIS PLANT
- Edible Shoots – raw or cooked. Can be blanched, steamed, poached, sautéed, fried, stir-fried, grilled, used in soups and stews. Can be pickled.
- General insect (especially bees) nectar plant
- Maritime plant – can tolerate salty conditions
- Ornamental plant – the “fern” is highly regarded
- Roasted seeds have been used as a coffee substitute
Yield: About ½ pound (0.23 kg) per crown or 20-25 spears per crown each year once established.
Spring. Cut or snap the shoots off at soil level. Once established (after year 3), the harvest can last for 3-8 weeks in the Spring. Less harvesting of weaker plants will allow it to grow stronger for next season.
Use right away. Asparagus does not store well. The flavor difference in freshly picked Asparagus and the stuff you buy at the grocery store is vast… makes eating store bought Asparagus rather depressing.
DESIGNING WITH THIS PLANT
USDA Hardiness Zone: 2-9
AHS Heat Zone: 8-1
Chill Requirement: Yes, see Special Considerations for Growing below.
Plant Type: Herbaceous Perennial
Leaf Type: Deciduous
Forest Garden Use: Herbaceous Layer
Cultivars/Varieties: Many species and varieties available.
Pollination: Most Asparagus are Dioecious (male and female flowers are on separate male and female plants). Needs both male and females within relatively close proximity for viable seeds to be developed. Pollinated by bees.
Years to Begin Bearing: 3 years before a significant harvest can be taken. No shoots should be harvested in the first year. We can harvest a few shoots the second year (6-8 spears per plant). By the third year, we can start to harvest in earnest (20-25 spears per plant). Things start to boom during the third year in a typical Asparagus patch. This delay in harvesting allows the plants to become firmly established and healthy.
Years of Useful Life: An Asparagus bed can be healthy and productive for 20+ years, although 10-15 years is more typical
PHYSICAL CHARACTERISTICS OF THIS PLANT
Size: 3-5 feet (0.9-1.5 meters) tall and 1-3 feet (0.3-0.9 meters) wide
Roots: Rhizomatous – underground runners that send up new plants
Growth Rate: Medium
GROWING CONDITIONS FOR THIS PLANT
Light: Prefers full sun
Shade: Tolerates moderate shade
Moisture: Medium moisture soils that are well draining
pH: prefers neutral soil (6.5 – 7.5); however, it can grow is a wide range of soils (4.3-8.2)
Special Considerations for Growing:
- Asparagus can be grown from seed or one year old plants known as crowns. If growing from seed, you will need to remove the fruit bearing female plants to avoid the seeds from spreading, along with new Asparagus plants, everywhere around your property. Growing from seed is cheaper, but adds another year to wait for a significant harvest. Growing from crowns is simpler and faster, but costs more for the plants.
- Asparagus needs a period of dormancy every year. This dormancy can be induced with cold weather or dry conditions (i.e drought). This rest period is essential for good shoot production.
Propagation: May also be divided in the early Spring. May be planted from seed. Germination takes 3-6 weeks.
Moderate. At the end of each season, the dried brown plant can be cut back and thrown into the compost pile. During the growing season, pests and diseases do like to attack Asparagus. Careful monitoring and intervention are needed to avoid, treat, or intervene with this. As I do not plan to grow Asparagus commercially, some disease and insect loss will be part of my expectation. I will intervene when I come across diseased plants, but by planting more than needed and losing some to disease and pests, the strongest will survive and produce better for me in the long run. Also, if you want White Asparagus, a lot more work is needed in covering the shoots to blanch them.
- Poisonous – berries are mildly poisonous (large amounts need to be eaten for this to be toxic). Consuming large quantities of the shoots has been reported to cause kidney irritation, but what exactly that means is not clear. Likely, one has to consume more than would be reasonable for a person to consume for this to occur.
- Can spread easily through seed if a female plant is present.