Culture
Most grow best in light or partial shade and need protection from strong winds. They are also frost tender. They like lots of water so don’t allow the fibrous, shallow, root system to dry out in dry weather; apply a thick layer of mulch and in sandy or free draining soils a drip irrigation system is useful. Though they grow on poorer soils, they need reasonable drainage and annual feeding to do their best; they are extremely heavy feeders, each plant needing around 0.7 kg of blood and bone (or something similar) in the first year and mature plants needing 5kg or more of fertiliser annually to give the best crops.
These plants need a very strong and secure frame to grow on, their growth is vigorous once established and the canes can grow several metres long each season. An annual, winter, pruning is recommended for the females plants - to keep them in check and to increase the yield.
Males are best pruned in spring after flowering, rather than winter, using the same method as the female plant (described below). The new growth produced by the male plants over the summer will produce the next season’s flowers for pollination of the females. Female flowers can be recognised quite easily; the small fruit swell at the base of the petals.
When you plant the vines, tie them to a post or support, let them grow vertically to the almost the top of the post, removing side branches as they appear, then cut off the top growth to just below the top of the post. This encourages side shoots that you can train along (laterally) the top wire.
In the second season encourage side shoots horizontally in both directions. Tie these on to the support but don’t twist them around the wires as this reduces sap flow. These side shoots will produce lots of vertical shoots along their length (the fruiting canes). Space these about 30cm apart along each lateral shoot (removing the excess) and then each year prune these back to 2-3 buds. After 3 years you can cut these back to the horizontal branches, to a dormant bud, to encourage new fruiting shoots to replace the older ones. Always remove old fruited canes, diseased and broken canes (both winter and summer) and water shoots in summer.
Propagation
Grafted known cultivars are best as the rootstocks as these grafted varieties are bred for disease resistance and vigour. However cuttings are also successful and these are a best taken with a heel; late summer cuttings strike best with bottom heat. Kiwifruit can also be propagated easily from seed but you would need to sex the plants to make sure you ended up with some females as well as males.