Growing feijoas

In New Zealand, it seems all you need to do is throw seeds at the wind for them to flourish, but elsewhere, apart from their native South America, a little more skill is required. I’m not a botanist, horticulturalist or soil scientist either but I hope that this information will point home growers in the right direction. See our Further reading page for books and other websites too.

Scroll down for information on:

• Optimum growing conditions
• Cross-pollination and why you need more than one tree
• Choosing trees and putting them in the ground
• Seedlings vs grafted cultivars
• Soil requirements and nutrients
• Common problems: water, chilling hours, heat and nitrogen
• Pests and disease
• Pruning

Other useful links on this site:

• Flower & fruit gallery – photographs of the flowering phase
• Cultivars – an ever-growing list of feijoa varieties
• Check the Community page for fan pages, forums and grower sites

OPTIMUM GROWING CONDITIONS

• Feijoas are hardy and tolerant to temperature extremes from -7°C to 40°C.
• Flower production is poor in areas with fewer than 50 hours of chilling. Optimum number of chilling hours is 100-200.
• Feijoas prefer cool winters and moderate summers (25°C to 33°C).
• The flavour of the fruit is much better in cool areas.
• Without any pruning, the shrub may reach 4.6m (15 ft) high and 4.6m (15 ft) across.
• A healthy mature feijoa tree can produce around 200kg of fruit each season.
• Some grafted cultivars of feijoa are self-fertile. Most are not, and require a pollinator.

CROSS POLLINATION AND WHY YOU NEED MORE THAN ONE TREE

Some varieties of feijoa are known as self-fertile (meaning they don’t need pollination from another tree) but even these varieties are likely to bear more fruitfully if they are cross-pollinated. All others require two or more trees for successful pollination and fruit formation, but even then it may not pay to rely on birds or bees to carry this out. It depends on where you live.

In case you’ve forgotten, pollination is the transfer of pollen from the male part of the flower to the female part of the flower. For feijoas, the pollen ideally comes from a different tree of a different variety in order to fertilise the plant and set the seeds or fruit.

In New Zealand, the primary pollinators of feijoas are bees, bumblebees, and medium-sized birds. The silvereye is a pollinator in the cooler parts of the South Island; the blackbird and the Indian myna, which feed on the sweet, fleshy flower petals, are pollinators further north.

In California, robins, mockingbirds, hummingbirds, starlings, scrub jays, towhees, and grey squirrels feast on the petals and are presumed to be assisting with pollination. Honeybees also visit the flowers.

In Australia, honeyeaters and noisy mynas are known to feed on the feijoa flowers. Bees are rarely responsible for pollination. If your tree is too dense and the birds can’t get in to the flowers, then pollination may not be occurring, just one reason that your tree may not produce fruit.

Hand pollinating

You can hand pollinate using a small natural fibre paint brush. Just dab the brush on the end of the stamen of one flower then repeat on another. Work your way around the tree a few times during the flowering period for a bumper crop. [From Barry’s Organic Gardening]. I’ve also picked flowers from neighbouring trees and brushed them across the flowers on my tree. You should hand pollinate every few days while the flowers are viable.

CHOOSING TREES AND PUTTING THEM IN THE GROUND

• Feijoa trees don’t transport well, so make sure you are planting them in a final spot.
• Choose the healthiest plant you can and ensure they are well fed through their early years.
• Watch out for the delicate feeder roots which are near the surface. Don’t dig around your feijoa and make sure they get a deep watering when needed.
• While the tree is renowned for its drought resistance, the fruit need a lot of water to set and can drop due to high temperatures and low water.
• Labels state that trees will fruit after three years, but some trees can take longer to mature. I’ve also read that if a tree does take longer to mature and fruit, then it is often a very heavy bearer as a result. So maybe leave it another year or two before you pull your tree out and try again.

SEEDLINGS VS GRAFTED CULTIVARS
There is a lot of argument out there regarding seedlings versus grafted plants. I kind of sit on the fence as I’ve purchased two seedlings and one is growing well and the other, in identical conditions, has not done as well. If it fails, I will replace it with a named grafted cultivar, one that flowers at a similar time to the one that is doing well.

Seedlings are sold in nurseries (and Bunnings, I hear) under the label acca sellowiana. They do not have any variety name such as Mammoth or Unique (please see our ever growing list of named cultivars.) They can be slower to fruit and are often used as ornamental or hedging plants.

In support of growing seedlings successfully, I’ve had a wonderful response from Leon Wilson (read his comment under places to buy quality feijoa trees) who has grown 240 trees in Western Sydney as part of a 15-year research project. He has great tips for getting trees to produce.

Elsewhere, I find forums littered with comments from people whose trees have not flourished, not flowered and not fruited. The response is uniform: they have most likely purchased a seedling and will do much better if they try a grafted named cultivar.

This comment from renowned New Zealand gardening guru Mary Robertson sums it up with the most authority:

Most feijoa trees offered for sale have been cutting-grown from commercially proven parents and you can expect quality fruit within three to four years. However cheaper seedling plants sold as feijoa sellowiana are still available. Avoid them if you are after large fruits in just a few years. The seedlings may not produce fruit for years and then the fruit quality and size will be variable. Seedlings are fine to plant if you requite a hardy ornamental hedge with the fruit as a bonus but you will be very disappointed if you plant seedlings for fruit production.

[This advice came from Mary Robertson’s website but the whole site seems to have disappeared, 12 November 2011. I might have to look for another expert who shares the same opinion.]

The cultivars are more difficult to grow, I understand, but once they flourish the fruit has recognisable and reliable characteristics… that means they will produce fruit that is true to form. They are more expensive and only available through specialised fruit tree nurseries.

SOIL REQUIREMENTS AND NUTRIENTS

There are many different variables that can cause yellowing, leaf drop, poor formation of fruit, root rot and mortality. It can be somewhat complex and the following is gleaned from multiple sites:

• Because they generally do not produce fruit until the third year feijoas only need a small amount of fertiliser placed around individual trees in the first three years. However in the fourth and subsequent years the trees bear more fruit and so require higher levels of fertiliser. It has also been suggested that rotted animal manure applied in autumn can increase yield.
• The feijoa is a heavy feeder. Feed with high nitrogen NPK fertiliser in late winter and well rotted animal manure in autumn. 200g of fertiliser per year of tree up to 10 years and 2kg per tree annually thereafter. Do not put fresh manure on to trees as it can burn the roots.
• An excessive amount of nitrogen can encourage the trees to grow vegetatively, producing more leaves and shoots rather than flowers and fruit. Therefore if nitrogen is low it may be best to apply it between August and December (southern hemisphere), before flowering begins.
• Nitrogen-heavy fertilisers can cause potassium deficiency and fruit cannot form.
• Potash and seaweed solution is often recommended.

COMMON PROBLEMS: WATER, CHILLING HOURS, HEAT AND NITROGEN
Water – there is no magical volume. You need to read your local climate, water deep when required and ensure that the plants don’t get stressed.
Chilling hours – it’s a reality that feijoa plants require 50-100 hours of cold or chill to set the fruit. Their natural climate is temperate highlands, so they simply do not fruit in warmer or really cold climates.
Heat – particularly in Australia, days of excessive heat in the 40s are highly damaging to fruit crops
Nitrogen – most plants need nitrogen, however, nitrogen causes excessive vegetative growth and can result in a potassium deficiency causing fruit to drop. Read the labels and avoid N-based fertiliser around fruit production time.

PESTS AND DISEASE

The main pests of feijoas include leafroller, mealybug, hard wax scale, greedy scale, fruit fly and Australian guava moth. The fruit fly and guava moth attack the fruit, while the others do not cause significant damage but in large numbers may reduce yields by damaging leaves and growing shoots.

Fruit fly
Recommended treatments include regular cover spraying of Lebaycid and a bait called eco naturalure, a registered organic fruit fly control spray. Please be aware that Lebaycid kills bees and if you are a bee lover, as I am, then a more bee-friendly option may be preferable, such as fine nets. Visit this great new website for strategies to protect your fruit from fruit flies: http://preventfruitfly.com.au/

Scale and sooty mould

Sooty moulds are fungi which cover plant leaves, stems and twigs in a black sticky substance. In almost all cases, the sooty mould is secondary to an infestation of insects that secrete honeydew. These insects include aphids, scale, mealybugs and white flies. Treating the insects will remove the source of the honeydew and dry up the sooty mould, which will eventually fall or wash off the foliage. The mould itself does not feed on the plant, however as it covers the leaf surface, it is blocking light and reducing photosynthesis, essential for plant growth.

That information came from the Yates Australia website and I have found two sprays of Yates Pest Oil to be successful with my sooty mould. White oil has also been recommended, which you can buy from a garden centre or make your own from vegetable oil and liquid soap.

Australian Guava Moth

Guava moth lay their eggs at the stem and style end and in cracks and crevices on fruit. The resulting larva feed inside the fruits, causing premature fruit drop. Pupation occurs in loose soil and ground debris. Guava moth damage may affect the productivity of a garden feijoa tree and the gardener may notice a hole in the fruit with frass (insect droppings) at the entrance. Guava moth infestation is obvious once the fruit is opened as the flesh will be brown and rotting. Pheromone traps are available which are designed to catch adult guava moths.

That information came from New Zealand Garden Science who confirm that these moths are now a problem in the north of New Zealand, as well as Australia.

Leaf roller

This photo shows some of the damage from a leaf roller, the larvae of certain moths. I just pick the whole leaf off as soon as I see them as there aren’t that many on my small tree.

Collar rot
This is caused by soil pathogens. Rub the base of the tree and if the bark comes away, you may need to treat with a copper fungicide. More often these trees do not come back but you will need to treat the soil as well before you can replant in the same place.

PRUNING
Feijoas respond well to pruning and can be trained to a small tree with a single trunk or pruned to form a dense hedge or screen. They can even be espaliered.

Carry out pruning in late autumn or early winter, shaping the tree and thinning out inner branches so that light and birds can reach the fruit next season. A great guide to pruning feijoa trees can be found on the ehow website.