What is asparagus?
For lovers of food, nothing signals that spring has arrived more than the appearance of asparagus in our markets. The distinctive flavour of succulent asparagus spears goes well with smoked salmon, Gruyère cheese, eggs and even with pasta. For a simple but impressive dinner party starter, bake asparagus in filo pastry with parsley, tarragon and goats’ cheese and serve with a peppery rocket salad.
So popular was this vegetable in France that Louis XIV had special greenhouses built to grow it. The Greeks and Romans thought it was a delicacy and used it for medicinal purposes. They ate it fresh in summer and dried it for winter use.
Even further back, the vegetable was included in an Egyptian decorative wall feature or frieze from 3000 BC. Asparagus grew wild in most of Europe, northern Africa and Asia but is now cultivated in many parts of the world including France, Spain, Poland, Germany, China and the USA.
Three types of asparagus are grown in Australia – green, white and purple. Green and white are the same variety of plant but purple asparagus is a different variety.
Green asparagus spears get their colour because the tips of the plant emerge into the sunlight, whereas the white spears are harvested while they are still underground (or they are grown in the dark to limit their exposure to light).
High levels of antioxidants (anthocyanins) in purple asparagus give it its unique colour. This variety of asparagus is sweeter than the green spears. You should keep the cooking time to a minimum so that purple asparagus retains its colour.
Why asparagus is good to eat
- Asparagus is a great source of vitamins (including vitamin A, vitamin C and folate).
- It contains minerals such as magnesium and iron, which are important for the production of blood cells.
- It is also a good source of dietary fibre.
- Energy – 100 g of asparagus supplies about 90 kJ.
How are they grown and harvested?
Asparagus seeds prefer a mild climate and sandy soil. The seeds rest (are dormant) during winter and grow in spring. Home gardeners grow asparagus from the crown, which is the underground root system of the plant.
The asparagus plant produces a deep root system and needs plenty of water to grow. The root system of the plant produces buds, and in spring these become the edible asparagus spears. Spears grow vigorously in humid conditions – up to 25 cm in 24 hours.
Green and purple asparagus are usually picked after the tips have emerged from the ground and have grown to about 20 cm. White asparagus is harvested as soon as the spear appears above ground so they do not become green. Lots of care needs to be taken so that the spears are not damaged. Asparagus spears that are not picked become woody and grow into fern-like fronds.
During spring and summer, each crown can produce spears for about six to seven weeks. It can take up to two years to produce the first crop of asparagus but carefully maintained plants can produce asparagus for up to 15 years.
Select asparagus that looks fresh, bright green and has closed compact spears with tight scales. Avoid buying asparagus if the stems look dry and the tips are damaged. Your asparagus is fresh if you can easily snap the bottom part of the spear off.
How to store and keep asparagus
To keep asparagus fresh, store it in an airtight plastic bag in the crisper compartment of your fridge. Use your asparagus as soon as possible.
How to use
- Steam asparagus spears and dip in a melted butter and lemon sauce for a simple, nutritious snack.
- Create a decadent breakfast treat – serve warm asparagus with poached eggs and hollandaise sauce.
- Try grilling asparagus on the barbeque – it goes well with a soy sauce and sesame oil dipping sauce.
- Use the woody ends of asparagus that you snap off before cooking to make a vegetable stock.
This page has been produced in consultation with and approved by:
Better Health Channel
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