When to plant walnut trees in New Zealand

Walnut trees are a popular choice for Kiwi gardeners wanting to grow their own nuts. But when is the best time to plant these trees in New Zealand? The answer depends on a range of factors, including your region, climate and the variety of walnut tree you plan to grow.

Choosing the right variety

Before you plant a walnut tree, it's important to choose the right variety for your climate and growing conditions. There are several varieties of walnuts that are well-suited to the New Zealand climate, including:

English or Persian walnuts

Black walnuts

California walnuts

Heartnuts

English and Persian walnuts are the most commonly grown variety in New Zealand. These trees prefer cool, moist winters and warm, dry summers. Black walnuts are more suited to colder regions, while California walnuts are best grown in the warmer coastal regions.

Planting in the right season

The best time to plant walnut trees in New Zealand is in late winter or early spring, when the ground is moist and the temperatures are cool. This allows the tree to establish its roots before the warmer months arrive. Planting too late in the season can result in the tree being stressed during the hot summer months.

If you're planting a bare-rooted tree, it's important to plant it as soon as possible to avoid the roots drying out. If you're planting a potted tree, it can be planted at any time of the year, as long as the ground isn't frozen and the temperatures aren't too hot.

Preparing the soil

Walnut trees prefer well-drained soil with a pH of between 6.0 and 7.0. Before planting your tree, it's a good idea to test your soil and make any necessary adjustments. You can also improve soil drainage by adding organic matter, such as compost or aged manure.

It's important to dig a hole that is deep enough to accommodate the tree's root system, but not so deep that the graft union is buried. The graft union is the swollen area at the base of the tree where the scion (the top part of the tree) has been grafted onto the rootstock (the bottom part of the tree). If the graft union is buried, it can result in the tree producing its own roots, which can lead to reduced tree vigour, smaller nuts and a shorter lifespan.

Caring for your tree

Once your walnut tree is planted, it's important to keep it well-watered and free from weeds. Mulching around the base of the tree can help to retain moisture and suppress weed growth. It's also important to fertilise your tree regularly with an organic fertiliser, such as blood and bone or fish emulsion.

Walnut trees can take several years to mature and start producing nuts. During this time, it's important to prune your tree regularly to encourage healthy growth and shape the tree. Once your tree is mature, it's important to continue to prune it regularly to promote good nut production.

Conclusion

Walnut trees are a great addition to any New Zealand garden, providing both shade and a source of delicious nuts. Planting the right variety and choosing the right time of year to plant can help ensure your tree thrives and produces a bountiful crop. And with a little care and attention, your walnut tree can continue to produce nuts for many years to come.