Time for something a little more unusual. It’s always good to occasionally step out of our comfort zone, and try and push the boundaries of what we think possible. Sure, there may be failures along the way, but there will also be unexpected successes which make us challenge accepted wisdom about what we can and can’t do. Trying to achieve the seemingly impossible or attempting a daunting task is at the heart of progress, and I think that gardening is as much about the growth of the person as it is about the growth of the plant. That is why this article will try and encourage you to plant a kiwi.
Kiwi fruits are members of the genus Actinidia - a group of 40 or so species which are native to Eastern Asia. It’s quite a broad church, ranging from large shrubs to vigorous vines which can climb 30m or more to the top of the forest canopy. They are widespread throughout much of China, Korea and Japan, and even up into the edges of Russia. You may well already be familiar with one member of the family, Actinida kolomikta, which is a fabulous ornamental climber. The leaves are long, bright green and covered with delicate splashes of cream and pink. It’s hardy, vigorous and a superb foliage plant to use at the back of a border covering a fence, or trained up a pergola.
The kiwi fruit which we find in the supermarket is Actinidia deliciosa. It’s the national fruit of China and has long been cultivated in that region. In the early 20th century it was introduced into New Zealand by a school principal who had visited Chinese missionary schools and proved so popular that it was quickly adopted by commercial growers. This is where it acquired the name of kiwi - after New Zealand’s national bird which is similarly brown and hairy! It’s a vigorous woody climber, producing stout pencil-thick stems covered in a layer of downy hairs. The large green pointed leaves form a magnificent cover, scrambling over a large wall or the side of a shed. Single white fragrant flowers appear in late Spring in clusters of three, all along the old wood. It’s here that the first problem arises - pollination.
Most commercial varieties of kiwi fruit are dioecious, which means that male and female plants are borne on different plants, and both have to be planted reasonably close to each other for pollination and fruit set. One male plant will produce enough pollen for up to eight females - but as each plant can grow up to 5m, that’s a lot of space to devote to one crop. Luckily there have been breeding developments which mean that self-fertile varieties are now available. Even so, crops will be heavier if a male plant is nearby. It pays to check carefully which variety you buy, if you only have room for one and hope to ever see some fruit!
The second issue is one of size. Left to their own devices, kiwi fruit vines will happily romp away and quickly outgrow their allotted space. If left untended, they will make lush growth up to 5 m tall - and put most of their energy into growth rather than flower and fruit production. Luckily, they produce flowers on one, two and three year old wood, so the best way to think of them is like a grape vine. Prune all new growth back every 6 weeks or so during the growing season, and this will keep them under control and increase yields. Every few years take out a little of the oldest wood (in early Spring), and train in some new wood to replace it.
The final obstacle is one of hardiness. Kiwi fruit are hardy down to about -7c, which means that in most of the U.K. they will want a warm, sunny, sheltered spot to thrive. As with many borderline plants, it is often the combination of wet and cold which is fatal, so improve the drainage with plenty of grit if your soil is on the heavy side. Otherwise plant on a slight mound to stop the roots from sitting in heavy wet soil. We have had a succession of milder winters recently, so I’m hopeful than even up in Yorkshire they will be fine, but I will cover the base of the plants with a thick mulch of bracken and straw, so even if the top dies back the plants will regrow. It might also be a good idea to keep some horticultural fleece handy to drape over the plant in the depths of winter.
At this point you may be throwing up your hands in defeat and wondering if it is worth all the trouble. It most definitely is - a freshly picked ripe fruit is an absolute treat. Shop bought fruit are picked extremely underripe in order to extend shelf life, so are not nearly as sweet or flavoursome. However, nature may have a readymade alternative for you, in the form of a close relative - the kiwi berry. Also known as the hardy kiwi, grape kiwi or Siberian gooseberry, it’s another species of the same genus called Actinidia arguta. It’s a climbing plant, similar in growth to a true kiwi fruit, but much hardier. It will tolerate down to -35c in its native Russia. The fruit is smaller - about the size of a large gooseberry - but the skin is smooth, thin and edible. It has the same kiwi taste, but even sweeter. The final bonus is that it is reliably self-fertile. The reason it has never been commercially grown is that the fruit has a short shelf life and they would never survive the journey from the field to the supermarket shelf. As home growers, this is of no consequence to us - they are so delicious you’ll have eaten them before you get back inside from the garden.
Hayward. Female. One of the very best, and still one of the most widely planted commercially. Excellent flavour. Flowers late.
Atlas. Male. An excellent pollinator, as it flowers for an extremely long period. Reliable and hardy
Jenny. The best self-fertile variety – compact in growth and quite reliable to crop, although another male plant nearby will help with pollination and yields.
Actinidia arguta ‘Issai’. The most widely available hardy kiwi. Small fruit which can be eaten whole, self-fertile, highly productive. An excellent introduction to the world of exotic fruit growing!
Actinidia arguta ‘Ken’s Red’. A unique variety producing small purple-red fruit, extremely sweet and delicious. Female, so needs to be planted with ‘Issai’.