A polytunnel allows you to grow a range of annual crops throughout the year. But for those of us who have less time to spend in the polytunnel than we would like, perennial vegetables offer a less time consuming option. These leafy vegetables are all perennial and will provide food for your table over several years, with far less effort than would be required of similar annual crops:
This member of the cabbage family produces heads that resemble mini cauliflowers but taste more like broccoli. After the main head has been harvested, it will produce around nine smaller but no less tasty heads that look and taste like any annual sprouting broccoli. Prevent it from setting seed and it will keep producing its crop every spring for around five years, sometimes longer.
Much sought after as a perennial vegetable, Daubenton's Kale is one of the best and most resilient perennial greens that you will find in the UK. Just like regular kale, this plant is extremely good for you and can be used in a range of recipes – but this kale is truly perennial and will continue to produce good, leafy growth for years.
Another cabbage-family option is 'Everlasting cabbage', which you can find in green and variagated varieties. When given good quantities of nutrition and water, this plant will be an abundant source of leafy greens throughout much of the year.
A less well known member of the Brassica family, perhaps, this plant may be familiar to anyone who has foraged along the seashores of Europe, where this plant can often be found. The plant has leaves much like any other Brassica but as it likes dry and free-draining conditions, could be an excellent choice for areas where rainwater can be scarce in summer.
Good King Henry is not very well known today, but was, for hundreds of years, a commonplace vegetable in cottage gardens across the UK. The leaves of Good King Henry can be used in much the same way as spinach, while the young shoots are a substitute for asparagus. Useful and versatile, Good King Henry is ideal for edible greens and for 'poor man's asparagus'. It is hardy and reliable and easy to care for, making it the perfect addition to a perennial polytunnel.