G’Day folks. Warrigal greens (Tetragonia tetragonioides) would have to be one of our favourite plants we grow around the patch here. In New Zealand, they’re called New Zealand spinach, and in Australia, it’s known as Warrigal greens, Native spinach or Botany Bay spinach. They’re native to many parts of the Asia-Pacific region as well as Chile where it can be found growing along beaches above the high tide mark and in dunes. Due to their hardy nature, they’re an ideal leafy green ground cover plant to grow in areas with sandy or degraded soils.
They’re are a low growing perennial that likes to sprawl across the ground but will climb a short trellis if given a chance. They make a fantastic ground cover acting as a living mulch, keeping the surface of the soil cool through the heat of Summer and providing a great habitat for bug-eating lizards to hide.
They’re very drought hardy and heat tolerant, which makes them a perfect English spinach alternative for us to grow here in the subtropics. They are pest resistant too, with grasshoppers being the only pest I’ve seen damage our plants so far.
Warrigal greens are grown primarily for their lush, succulent green leaves which if given the right conditions can reach about 15cm / 6” in length. The softer tips of the stems are also edible, so there is very little waste involved when processing the greens.
When and Where to sow
Warrigal greens grow well in temperate regions but only as annuals in areas that receive heavy frost. Luckily, they do transplant well so they can be started off indoors and transplanted out once any chance of frost has passed. For those that are sowing the seeds straight out in the veggie patch, it’s best to wait until the soil temperature is over 18°C / 64°F.
Temperate – Warm Temperate
Sow into trays at the start of Spring, then transplant out into a full sun position in the garden when the last frost has passed.
Sow into trays at the start of the last month of Winter then transplant out when the last frost has passed. Direct sowing them into a sunny position in late Winter works well if like us you don’t get any frost events. I’ve found that they do struggle through our hot subtropical Summers if grown in full sun. However, they will continue to thrive if let grow in a moist, shaded position.
Warrigal greens are best sown out into patch mid-Autumn and grown through Winter in tropical regions. Those in these regions might want to consider planting them in a spot where they will be shaded through Summer if you want to keep them growing actively.
Warrigal greens are a very hardy plant that will survive in harsh conditions and poor soils. They will, however, produce large lush greens for harvest if you give them a little extra TLC. Provide them with some free-draining organic-rich soil and top dress the bed with mulch to help retain moisture, and they will thrive proving you with more greens than you can use. They also grow well in containers in a good quality potting soil and can make a rather attractive ornamental balcony plant.
Sowing the Seeds
Warrigal greens seeds have a unique shape and a very hard exterior. This hard outer coating has caused more than a few gardeners I know to give up on them sprouting them after a few weeks.
The easiest way to get these little fellas popping out of the soil is to soak the seeds for 24 hours before sowing them out. Sow the seeds about 13mm / ½” deep and space the plants about 60cm / 2ft apart as they will sprawl.
Seedlings started off in containers are ready to transplant out once the second set of true leaves have formed, which is when they’re round about 7½cm / 3” tall.
Water and Fertiliser Requirements
While they are a drought hardy plant, they will be more productive if regularly watered. If they do go through a period of low water, you can give them a trim back and a good water to stimulate new tender growth. Warrigal greens only need to be fed with a top dress of compost or handful of slow release organic fertiliser midway through the growing season. I do feed plants in containers with organic based liquid fertiliser every few months just to keep them producing well.
Small yellow “perfect” flowers will first appear on the stem of the plant at the leaf junction. Once fertilised they will swell into a green pod with horn-like growths appearing at the top. As these seeds mature they will turn brown and the small horns will often dry out into sharp spikes. You can collect the seeds from the plants once the seeds turn brown and come off the stem when touched.
Just a word of warning, Warrigal greens will set hundreds of seeds if left to mature. Fallen seeds will germinate as soon as conditions are right and they will over-run garden beds if given a chance. You can also take advantage of this and use the excess to feed chickens or pop it into the compost bin to recycle the nutrients back through your soils.
Cooking and eating Warrigal greens
Warrigal greens are high in Vitamin A, C and B6. They also contain relatively high levels of calcium, iron and magnesium. They are a versatile green that has a strong spinach-like flavour so make a great spinach substitute. As mentioned above, the tender young stems are also edible.
Warrigal greens, like many leafy greens, contain low levels of oxalates. If you are consuming them in large quantities, it is recommended by many that you blanch the greens for 1 minute to help remove these oxalates.
To blanch the greens, you bring a pot of water to a gentle boil then add in the greens.
After about a minute, the greens are removed and can either be used straight away or, if you want to store them for later use, cooled in a bowl of cold water. The cooled greens are then drained with the excess water squeezed from them before being portioned out and frozen for later use.
Now to be perfectly honest I’ve read conflicting information about the levels of oxalic acids that we can safely consume, so it is probably something you should research for yourself if you do have concerns.
Hope you've picked up a few pointers that will help grow a load of these fantastic greens for yourself. Cheers & happy Growing, Rob.