How to grow Avocado in New Zealand

Where to plant

Choose a warm, sunny spot sheltered from wind and frost, with free-draining soil. Avocados will not tolerate wet feet: in heavy or clay soil, fork in gypsum and plant on a raised mound so water drains away from the roots. Young trees are especially frost tender and need frost cloth on cold nights for the first few winters.

• Northland and Auckland: the best regions. Plant from September to November in a sheltered, well-drained spot.
• Waikato and Bay of Plenty: coastal Bay of Plenty suits avocados best. Inland Waikato needs a warm, sheltered spot and frost cloth while young. Plant in October or November once frosts are over.
• Wellington and the lower North Island: plant from September to November in the warmest, most sheltered spot you have, out of the wind.
• Nelson and Marlborough: marginal. Plant in October or November on a raised mound in a warm, sheltered spot, and use frost cloth while young.
• Central North Island, Canterbury, Otago and Southland, and Central Otago: our calendar marks these as unsuitable, as frosts kill young avocados.

Choosing a variety

Avocado flowers open as female and male at different times of day, and varieties are grouped as type A or type B by that timing. A tree can set fruit alone, but cropping is better with one of each type nearby.

• Hass (type A): the main New Zealand avocado, with black, pebbly skin when ripe and rich, nutty flesh. A large tree.
• Reed (type A): large, round green fruit.
• Bacon (type B): green-skinned and more cold tolerant than most, and a useful pollinator for Hass.
• Cleopatra: a newer, compact variety for smaller gardens, with black fruit picked from about July to December.

How to plant

1. Work organic matter or blood and bone through the soil. On clay, add gypsum and build a mound to plant on.
2. Dig a hole twice as wide as the root ball and to the same depth.
3. Remove the tree from its pot, tease the roots gently and cut away any that circle the pot.
4. Plant at the same depth as before, backfill and form a ring of soil around the tree to hold water.
5. Water in well and mulch with wood chips or pea straw, keeping it clear of the trunk.
6. Protect the young tree from wind and frost with shelter or frost cloth.

Watering and feeding

Water deeply about once a week in hot, dry weather rather than lightly every other day, and keep the root zone mulched all year. Avoid overwatering in winter, as wet soil invites root rot.

Feed with a fertiliser for citrus and fruit trees in spring and late summer, increasing the amount as the tree grows. Renew the mulch each year.

Pruning and care through the year

• Prune lightly after harvest, removing dead or wayward branches. Any major pruning is best done in late winter.
• If a tree flowers well but sets no fruit, the usual causes are cold weather during flowering or too few pollinators.

Harvesting

Avocados do not ripen on the tree, so the fruit can be picked over a long season as you need it. Hass is usually picked from about November to March. To test, pick one or two full-sized fruit and leave them on the bench: if they soften within about 7 to 12 days, the crop is ready. Cut the fruit off with a short piece of stalk attached.

Ripen fruit at room temperature until it gives slightly, then keep it in the fridge for 2 to 3 days. Mashed avocado with lemon juice freezes well.

Growing in pots

A compact variety can be grown in a pot at least 60 cm wide and deep, such as a half wine barrel, in full sun and out of strong wind. Use a quality potting mix, water regularly but never leave it waterlogged, and feed through the flowering season. Potted trees can be moved under cover in frosty districts.

Using it

Eat avocado fresh in salads, on toast or as guacamole. Add lemon or lime juice to cut flesh to slow browning.