Gardening: Heirlooms of edible treasure

Citrons reach the size of a football and are used for fragrance and candied fruit. Photo / Meg Liptrot

It was a crisp, clear winter's day when I caught up with Rob Velseboer at the 7.3ha property in Riverhead he owns with his partner Murray Joyce.

Their business, Heirloom Organix, specialises in growing organic vegetable and herb seedlings and they are regular stallholders at the Grey Lynn and Parnell farmers' markets. But their lesser known passion is the heritage fruit tree collection they've amassed over the last15 years.

The 1.2ha pip and stone fruit orchard within the property features trees grown from cuttings or fruit stones from remnant orchards and gardens around the Auckland region. They also have some unusual citrus trees, including the ancient (and huge) Citron.

Trees are rigorously edited in their orchard. If a specimen has not performed in five years by way of tree health or fruit taste, out it goes. This means they have trees that have proven themselves for Auckland's bio-region.

Rob says this is something they believe in and love. It's not a money-making thing. They began by taking cuttings from old trees at Murray's great-grandmother's property across the river in Riverhead, then learned about grafting. The collection grew from there.

This is very much a family affair. Passion for horticulture runs in Rob's veins. He grew up immersed in it and family members offshore are well known in the nursery business. Even his name means "field farmer" and the property Rob and Murray now call home was once Murray's grandmother's farm.

The orchard acts as a living plant bank for the Forgotten Fruits nursery near Kaiwaka, where cuttings are grown on for sale. Many of these fruit tree varieties are named after the locations where they were found, such as the evocative "Chookhouse Peach".

Health benefits of heritage fruit

Rob points out that research by Mark Christensen (who discovered the impressive anti-cancer apple "Monty's Surprise") shows that even "Red Delicious", which is not a particularly old variety of apple, has many more nutrients than modern apple cultivars.

He says for the average home garden, apples can be a challenge as they often require an extra tree for pollination, but get a self-fertile plum and "you're away laughing". "Feeding families fresh fruit and veges makes such a difference (compared with) the stored stuff. A lot of gardens can fit a plum tree. Cycads and bromeliads? I'm not a big fan of amenity plants. Plant a plum tree, for goodness sake!"

Healthy Soil, Healthy Trees, Yummy Fruit

Rob and Murray's orchard is on clay loam and is naturally acidic. Every couple of years they spread lime in the orchard. This reduces soil acidity and the calcium in the lime is important for cellular strength and helps buffer plants from disease. It has been an organically certified property for 12 years, so inputs are minimal. They spread a fertiliser mix of rock dust, seaweed and wormcastings from Environmental Fertilisers around the dripline of the trees each year and mulch with chipped, disease-free orchard prunings. They also spray tree with fish and seaweed fertiliser in early spring.

Each tree is underplanted with comfrey and borage, spring bulbs, wild alyssum, cleavers, nasturtium and phacelia.

These plants help to build soil and attract beneficial insects. To encourage pollination, the orchard also has a number of beehives, and beeswax is the main ingredient in their pruning paste. Pests are reduced by spraying bare trees in winter with organically approved lime sulphur to remove lichen and dead leaves where pests can overwinter.

An ingenious codling moth trap is stationed in the middle of the orchard. This comprises a stand with an LED bulb and broad metal lampshade, which hangs closely over a shallow dish filled with water and detergent. The light attracts the moths which are caught in the water.

Hot tips from Rob

Stake new trees for first year, in the second remove the supports. "We don't let our trees get lazy."

Prune deciduous fruit trees in summer once they've finished fruiting. This reduces the risk of diseases such as silverleaf and canker, which are often spread by pruning in winter.

Peach trees perform best when they are grown from seed. Grow in a mesh-fenced chook run - the manure boosts soil fertility and is a perfect addition when making compost. Fallen fruit is kept out of your dog's reach, as serrated peach stones are dangerous for dogs' digestive systems.

Red-fleshed plum "Tamaki Special" is one of Rob's favourites, and suits Auckland gardens. He says plums are fine if you have dogs, as the stones pass straight through.

• Hear more from Rob in weekly webinodes on: organicediblegarden.co.nz