For those with an invested interest in the produce calendar, the turn of daylight saving in early spring signals the arrival of the asparagus season. For 8 weeks of the year, from September to November, the perennial vegetable escapes its soil prison, pushing out its slender young shoots for harvesting.
Historically speaking, asparagus (Asparagus officinalis) is regarded as one of the more ancient vegetables, with evidence of its presence in Egyptian tablature and featuring in some of the oldest recorded recipes from the early Romans. It is considered one of the more opulent vegetables (yes there is such a thing as a vegetable hierarchy), most likely due to its involved growing process, small harvest window and delicious taste.
Luckily for you, asparagus grows extremely well in most of Aotearoa’s climates, preferring mild to cold conditions to flourish. While you can grow asparagus from seed, it is much less time-consuming to plant from crowns; a crown is an established asparagus root system, 2 years old, with a small central fleshy head. Seedlings can take 1-2 years to grow before transplanting to their permanent position, whereas crowns can be directly planted in the desired harvest location.
Asparagus crowns are best planted in winter and can be purchased from most local garden nurseries – common varieties of asparagus are the ‘Mary/Martha Washington’ and ‘Connover’s Colossal’.
Once an asparagus plant is established, it will continue producing annually for 20 years or more, so it is well worth the initial time and patience required.
Follow these steps for successful asparagus growth and harvesting:
- Before planting, prepare the soil with organic matter, garden lime (to create an approximate pH of 7), and a pre-planting fertiliser.
- Dig a trench row to plant the crowns into, approx. 20cm deep. Space the crowns approx. 40cm apart at the bottom of the trench, spreading out the roots a little, and cover with approx. 5cm of soil. If planting multiple rows, each row should be 30-40cm apart.
- As the asparagus stems grow, gradually cover them with soil (ensuring you do not cover new shoots). By autumn, the trench initially dug should be filled with soil as the stems have grown.
- Apply a general fertiliser during summer to encourage growth. Try to keep the soil weed-free and water regularly as necessary.
- Late autumn and into winter, the stems/ferns will turn yellow – at this stage, cut back the asparagus close to ground level (2-3cm from the soil surface). The yellowed ferns make excellent compost. At the end of winter/start of spring, apply more fertiliser to encourage spring growth.
- Here comes the crucial part – DO NOT be tempted to cut asparagus spears on the first spring after planting, otherwise it will be the end of your plant. From the second spring onwards, you can start cutting spears when they appear, once they are at least 15cm long. Continue cutting spears as the grow for approx. 8 weeks – if you harvest much later than this there will be poor growth the following season.
- With each year, as the plants mature, the yield should increase, hitting peak spear production by year 4-5.
- Pest control is often unnecessary for asparagus – they can be attacked by asparagus beetles from late summer, which can be controlled by removing any dying foliage from the plant.
- If companion planting (highly recommended), grow alongside tomatoes, basil or parsley.
Nutritionally, asparagus is a reasonably good source of antioxidants, fibre, iron and Vitamin A and C. To try and retain some of its signature crunch and verdant appeal, the best methods for cooking asparagus are blanching, quick-roasting or grilling. Alternatively, fresh raw asparagus can be an excellent snack or crunchy addition to salads.
As we are at the beginning of November there are only a couple of weeks of asparagus season remaining, and the recipe below is a must-try before the season ends. Here I use a quick-roasting method, pairing the asparagus with citrus flavours and a vibrant hazelnut romesco, the outcome being a gorgeous side dish that is sure to become a whānau favourite for spring seasons to come.
Citrus-Roasted Asparagus with hazelnut romesco, rocket & mint (vegan)
Ingredients (serves 4-6 as a side)
- 500g asparagus, woody ends trimmed
- zest and juice of ½ orange
- zest and juice of ½ lemon
- 2 Tbsp olive oil
- 1 cup (140g) hazelnuts, roughly chopped
- 3 Tbsp maple syrup
- ¼ tsp sea salt
- ⅔ cup (90g) maple-roasted hazelnuts
- 200g roasted red peppers (from a jar)
- 2 Tbsp tomato paste
- 1 tsp ground paprika
- ½ tsp sea salt
- ½ tsp cracked black pepper
- 1 Tbsp balsamic vinegar
- 1 Tbsp chopped fresh oregano (or 1 tsp dried)
- ¼ tsp ground cinnamon
- 2 cloves garlic, finely chopped
- 3 Tbsp olive oil
- 1 large handful fresh rocket leaves
- 1 handful fresh mint leaves
- Preheat the oven to 180°C (160°C fan-forced).
- First make the maple-roasted hazelnuts. Place the chopped hazelnuts in a single layer on a baking paper-lined tray. Drizzle with maple syrup, sprinkle with sea salt and roast in the preheated oven for 15 minutes until golden brown. Remove from the oven and set aside to cool, you will use two-thirds of the hazelnuts for the hazelnut romesco and one-third to decorate when serving.
- For the citrus-roasted asparagus, trim the woody ends from the asparagus spears and place in a single layer in a large ovenproof dish. Sprinkle with the orange/lemon zest, squeeze over the orange/lemon juice and drizzle with olive oil. Place in the preheated oven and roast for 15 minutes until the asparagus is just tender.
- For the hazelnut romesco, place all ingredients in a blender/food processor blitz until well-combined to form a relatively smooth sauce.
- To serve, lay the roasted asparagus spears on a serving platter, spoon over the hazelnut romesco (leaving the asparagus tips undressed), then top with the rocket leaves, fresh mint leaves and remaining maple-roasted hazelnuts. Best served warm, but happily eaten cold.
For this recipe and more, visit www.treatrightnz.com or follow @treatrightnz on Instagram.