What is grafting? Grafting is a procedure where we combine two varieties of fruit trees from the same family, for example we can use one kiwifruit variety for rootstock such as Bruno or Bounty and graft another variety of fruiting kiwifruit on it, such as G3 or Hayward.
When rootstock is mature enough and meets our standards, we prepare it for grafting; you have read about our pre-grafting preparation in our previous article. Budwood is cut into scions with one to two buds on them. Buds must always face upwards when grafting. Most common grafting techniques used in SCH nurseries are Whip-n-tongue and Cleft grafts.
When scion is matched onto rootstock, we wrap it with grafting tape for various reasons. One, we ensure the stability of union; additionally, it protects union from drying out, as well as protects it from potential infection. Finally, we paint the top of scion with special dressing or paint. This again keeps the moisture in and prevents infections entering through the wound.
At SCH we have prepared throughout the winter and spring for grafting season that starts in late November and lasts until February. This year we are grafting 3 fruiting varieties, green, gold and red kiwifruit. 2020 was the first year when licences were issued by Zespri for commercial growth of red kiwifruit varieties (female and male).
Grafting in SCH nurseries start with Bruno rootstock as it grows and matures faster than Bounty. Majority of it is grafted until end of December. We start at our largest site at Bayview, Pukehina, where we graft approx. 150,000 plants in 6 weeks. In January we continue grafting at our sites at Clear Springs, Joyce Rd and Pyes Pa Rd. As Bounty matures towards the end of January, we graft it last. First buds start to break 10-14 days after grafting and at the same time we start noticing callusing of the union. We can tell if the graft was successful after a months’ time.