Fruit - Apricots

Apricots are at their best when picked ripe and eaten soon after, and that means that ideally you have your own apricot tree. Add to that the fact that most shop-bought apricots are grown to look appetising when displayed rather than taste well, and you have two very good reasons why every food garden should have an apricot tree!

photo 1: Moorpark apricots

This is a blog post in the Fruit-series by Max B and Max K. It covers buying, planting, pruning, grafting and pest control of apricot trees, and harvesting and storing of their fruit. Thank you, Max K, for your expert-feedback and valuable contributions to this blog post! 

General cultural notes for apricot

• Lifespan: apricot trees live a lot longer than peach and nectarine trees. A productive 25-year-old apricot tree is not uncommon.

• Soil: apricots prefer lighter soils than apples and pears. They do not like clay soils with bad drainage, so if clay soil is what you have, spend time improving your soil before planting your young apricot tree, or create a big mount of free-draining soil and plant your apricot tree on top of that.

• Water: apricot trees do not like dry conditions. The best-tasting fruit will be produced when these trees are regularly watered throughout the season. Drip-irrigation is ideal because wet foliage should be avoided, especially in humid conditions. Irregular rainfall can make apricots split. Regular drip irrigation may avoid this. 

• pH: if pH is below 6.5 apply lime or dolomite in winter. For apricot trees dolomite is preferable over normal lime, as it contains potash.

• Fertilisation: a fertiliser high in potassium and phosphorous and low in nitrogen is best for apricots.  Well-composted chicken manure is ideal along with worm castings and worm juice. Drinks of seaweed solution during the growing period are also helpful. Apricot trees love potash. If the pH is right, and you are therefore not going to apply dolomite, instead apply sulphate of potash in spring. Potash improves water retention, encourages strong flower and fruit development and improves disease resistance. Apricot trees in commercial orchards may have a tough life compared with a single apricot tree that is well looked after in a home garden. However, come harvesting time, the home garden apricot tree may have fruit that is not evenly ripe. Uneven ripening of apricots (one side is ripe, the other side is not) can be the result of too much nitrogen and too much water in the later stages of fruit ripening!  Feed your apricot tree no more than once a year in early spring.  Apricot leaves like the ones in the photo below are a sign of a magnesium deficiency that will be gradually overcome by applications of Epsom salts

Apricot tree that needs magnesium

• Grass and weeds: apricot trees root shallowly. For young trees especially, remove all grass between the stem and the drip line (that is the circle where the foliage ends).

• Mulch: put a good layer of mulch around your apricot tree. It will help moisture retention and result in better quality fruit. Woody mulch is preferable over other types of mulch as it encourages fungi and other micro-organisms that are beneficial to fruit trees. Apply a generous quantity!

• Flowering: fruit buds on apricot trees need between 300 and 900 hours of temperatures below 7 degrees Celsius in order to form fruit, so Tasmania’s winters are ideal. Apricot trees have a short flowering period, usually in August. If there is frost during flowering or if there is a lot of rain, bees may not pollinate the blossoms, and there may be no fruit or few fruits that summer. 

• Pollination: Most, but not all, apricot varieties are self-fertile. Self-fertile apricot varieties do not need pollen from another tree to bear fruit, so you need just one tree to get apricots (and of course  bees to do the fertilisation for you). If you have the space available, however, have two trees, because most apricot trees produce more fruit if there is another apricot tree nearby. A space-saving alternative is to graft another variety onto your tree (see under ‘grafting’ below).

• Grafting: grafting another variety onto your apricot tree is a great way to combine an early variety with a late variety, so you have fresh apricots over a longer period of time. It can also result in better pollination and therefore more fruit. For more on grafting see A Look at Grafting on this blog.

photo 2: apricot blossoms on a short branch called 'spur'

Buying an apricot tree

By far the best time of year to get an apricot tree is when dormant bare-rooted trees are for sale at nurseries and hardware stores in mid-winter.

Bare-rooted trees that are left in nurseries at the end of the dormancy period are potted up and are then for sale for the rest of the season. Buying trees in pots will be fine in many cases, but you don’t know how long the tree has been in the pot, it will cost more, and the tree may not respond well to being transplanted while not dormant.

Ideally you start thinking about and planning for your new apricot tree in mid-autumn. When trees become available in mid-winter, you will find them in hardware stores, but the choice of varieties will be limited. In order to get some of the tried-and-proven varieties that do well in Tasmanian conditions it might be better to order a tree from a reputable Tasmanian nursery when they open for fruit tree orders in late autumn. The trees will then be ready for pickup in July – August.

All apricot trees are grafted these days, so you get the benefit of good fruit and a rigorous root system. 

There are early or late ripening varieties. In Tasmania, with its unpredictable cooler climate early to mid-season varieties might be most rewarding.

Consider a dwarf tree (a tree that will stay small because it is grafted onto dwarfing root stock), as it will take less space, and will be easier to maintain.

When picking up the tree from the nursery in mid-winter, inspect it right there at the nursery before taking it home, including the roots. Ask for a different tree if it does not look healthy. Inspect the graft. There should be no split bark or gum oozing from it.

photo 3: Rival apricots

Apricot varieties recommended for cool regions (that is most of Tasmania): 

• Brillianz: self-fertile, smaller tree than its relative Moorpark, eat fresh, preserve, dry
• Goldrich: not self-fertile, large fruit, productive, acid if picked too early, Rival is a good pollinator
• Moorpark (see photo 1): self-fertile, superior rich flavour, available on dwarf root stock
• Rival (see photo 3): not self-fertile, Goldrich is a good pollinator for Rival
• Tilton: self-fertile, consistent cropper, sweet-tart flavour, early variety resistant to late frosts

Planting an apricot tree

You can make a really good start with the prevention of pests by planting your tree in a well-drained location with full sun (6-8 hours during the growing season). Make sure there is always ample opportunity for air flow between trees, even when they reach full size.

A damaged trunk is an easy access point for fungi. Don’t put your apricot in a situation where you may mow right up to the trunk and damage it. It is best to remove all grass and weeds around a young fruit tree, cover the ground with woody mulch, and keep it weed-free.

Find a spot where the tree will be able to reach a good size without shading other plants.

Avoid planting an apricot in a very windy spot as branches may break and soil may dry out.

It is best to prepare the spot, where the tree will be, a number of months before planting time.

Explore the spot by digging a large hole. Assess the quality of the soil. Fill the hole with a bucket of water. If the water is still there a few hours later, find another spot, or create a mound that will drain well and plant the tree in the middle of the mound.

Are you finding that roots of other trees have claimed this spot? If so, your new fruit tree may have too much competition from nearby trees. Fill the hole with a mixture of soil and mature compost and/or mature manure. Let this settle for a few months, until mid-winter, when you will plant your tree.

When arriving home with the tree in mid-winter, plant it as soon as possible. If you don’t have time right then, heel it in a temporary position (for up to a few weeks) by burying the roots in some loose soil and keeping the soil moist.

How to plant your young apricot tree:

1. Remove all saw dust or other moisture-retaining materials around the roots.
2. Don’t prune the roots unless they are very long.
3. Soak the tree overnight in a bucket of water + seaweed solution.
4. The next day, plant it deep enough, so all the roots are covered by at least 10 centimetres of soil. Make sure that the spot where your variety was grafted onto root stock, is well above ground level.
5. Put two stakes in the ground at opposite sides of the tree, and tie the tree to the stakes with flexible tree ties.
6. Immediately surround the young tree with mesh if wildlife is a problem.  Rabbits love eating the bark of apricot trees in spring and autumn.  Possums will eat all the new shoots.

Pruning at time of planting is not in the list above. Apricot trees are prone to fungi attacks. While your new apricot tree is dormant it can’t heal pruning cuts quickly and this makes it a target for fungi, so it is best not to prune at the time of planting in mid-winter. Prune it once it has woken up and you see some activity. That may be in early October.  At that time prune your new young tree so it begins to take on the shape of a vase. Cut away most of the central stem. Leave untouched four main side-branches that are most promisingly arranged around the middle. Remove other branches that are not well-positioned, or weak, or broken.

Most nursery-tree growers do not prune their young trees at all before they go to the customer, because they know that customers like big well-developed young trees. Many buyers also don't prune it. If the young tree is not pruned when it has come out of dormancy, its often-minimal root system will struggle to feed all the branches, and the shape of the tree will not be ideal for a productive life.

In its first year in the ground the young tree will focus on forming a good root system. Don’t be disappointed if not a lot happens above ground, and don’t expect any fruit.

Water a young tree well during its first year as its root system may not yet be developed enough to cope with long periods without rain. In that first year wait with compost, manure and foliar feeding until the tree is recovering well in mid-summer.

If your tree came in a pot, do not just plant it straight from the pot into the ground, because roots may have started to curl around in the pot, and will continue to do so in the ground (restricting the tree’s growth), if you don’t correct this problem. Remove most of the soil, straighten the roots, and then spread them out in a hole that is big enough to allow roots to go outwards. Don’t cut the roots unless they are very long. Give the tree a hard prune, so it has less foliage to take care off, while it recovers. Planting an apricot outside the dormancy season is not ideal, so keep an eye on it, and make sure its soil remains moist, but not sodden, at all times.

Pruning an apricot tree

The number one pest problem with apricots is not insects but fungi. Pruning to keep apricot trees open to air and sun is the number one strategy to minimise or ideally avoid fungal problems.

If you prune in winter, cuts won’t heal quickly because the tree is dormant. Slowly healing cuts that are exposed to cool and wet conditions are an easy target for fungi. Avoid pruning in winter if at all possible.

Pruning provides ventilation and therefore is a preventative measure against diseases. It also makes pest control, netting, and picking of fruit far less arduous.

Ideally you train a young apricot tree to take on a particular shape and height in its first four years in the ground. If you do this well, and its shape is right, the tree then needs less pruning in subsequent years. When it is pruned less, the tree is not encouraged to ‘grow wood’. Instead, it will spend more energy ‘growing fruit’. Ideally in old age, a well-shaped apricot tree does not need a lot of pruning and continues to produce well.

General pruning rules:

1. Use sharp clean secateurs: see 'getting the best out of your secateurs' in blog post Pruning Berries
2. For a young tree focus on getting the shape of the tree right, not on getting fruit.
3. Make clean wounds that are as small as possible.
4. Do not treat wounds with wound sealants. It might do more harm than good.
5. To avoid taking diseases from one tree to the next, before starting on the next tree, wipe secateurs with methylated spirits or a mix of water and household bleach.

Prune in autumn once the foliage at the end of branches has stopped growing and before the tree goes dormant. At that point in time sap is no longer rising in the tree (hence no new growth), but the tree still has enough energy to quickly repair the wounds that the pruning has made. Late April might be a good time, but it can be earlier or later, depending on the weather, and depending on the variety of the tree.

If you prune too early the tree will produce new growth after pruning, and that new growth may not be hardened enough to cope with frosty conditions in winter.

Apricot trees form spurs, short stocky branches that bear fruit (see photo 2 above).  These spurs can have fruit on them for up to five years, so do not remove these spurs at the end of the first year of fruiting, thinking that they won't form fruit in the future.

Over-vigorous apricot trees can be kept under control by repeated tip-pruning during the growing season.

How to prune a free-standing apricot tree:

1. Always work towards making the tree a vase shape around an empty middle.
2. Improve ventilation by cutting branches in the centre and those that begin to go inwards to 20 centimetres (9 inches) long.
3. Cut away branches that cross each other, and that may damage each other in windy conditions.
4. Cut away diseased or damaged wood.
5. Don’t allow more than five or six main side-branches to form the vase off the central stem.

T-shape is the most commonly known form of espalier. This shape is not very suitable for apricot trees because their wood is brittle and might crack if forced to bend too much.The espalier shape most commonly applied to apricot trees is fan-shape, also called palmette (see photo below).

photo 4: a palmette espalier

How to prune an espaliered apricot tree:

1. When the tree is young focus on getting promising branches to go along the 45-degree lines, using bamboo or other straight sticks as support.
2. Cut away all branchlets that go down from these 45-degree main branches.
3. You can see what wood is one year old because it is lighter-coloured than older wood. Cut one-year old wood by 50%. It will produce fruit on the remaining 50%. The aim is to get less fruit but better-quality fruit.
4. Cut away diseased and damaged wood.

Thinning apricots

Thinning fruit results in more even crops over the years. Not thinning will lead to a large crop that season, followed by a small crop the following season. It is called biennial bearing. Trees produce well one year, not much the next, then well again and so on. Early and rigorous thinning results in more even crops over the years. Thinning allows the remaining fruits to become bigger and tastier.

Whereas I rigorously thin my peaches and nectarines by hand every year, most years the wind does the thinning of fruit on my Moorpark apricot, but that may be just in my garden. 

Imagine the approximate size of a mature apricot, and make space between the fruits, so, when fruits develop to full size, the fruits still don’t touch.

photo 5: remove the middle one

Ideally you thin apricots when the fruit is quite small, just as they have developed pips. You can thin them later of course, but the longer you leave it, the more energy the tree spends on a lot of fruit that you are going to remove. Growers are very busy thinning early in the season. 

Controlling apricot pests

Birds can be a devastating pest. In many gardens early netting is a must to protect fruit. You can net the whole tree if it is not too tall, or surround clusters of ripening apricots with bags made out of netting.

In Tasmania fungi are next on the list as pests affecting apricot trees. The following practices go a long way towards avoiding fungal problems:

• Prune trees to keep them open to sun and air.
• Prune in late summer or autumn, not winter.
• Throughout the season always remove pest-affected flowers, fallen fruit, mummified fruit and fallen branches, spoiled fruit and pest-affected leaves, as soon as you see them. Do not put them in your compost heap, but remove them from your garden.

Apricot trees are not affected by Curly Leaf, so spraying with copper-based fungicide, lime-sulphur fungicide or Bordeaux is not needed for that reason.  

Apricot trees can suffer from a fungus called Shot Hole, so called because brown circles form on leaves, and then the dead foliage within the circles falls out.  If you see this on your apricot tree it is too late to do anything about it then. However, spray next winter with a copper-based fungicide twice with a fortnight in between, and it will not re-occur.

photo 6: Shot Hole

Brown Rot is a fungal pest that is common in Tasmania. It affects blossoms, leaves and fruit. It usually occurs after wet humid weather. Australia's best stone fruit is grown in warm dry areas. Irrigation at ground level is a good way to limit or avoid Brown Rot.

photo 7: advanced Brown Rot

Here are the visible signs of Brown Rot:

• Brown, wilted blossoms 
• Dark, sunken spots on new wood and brown, hanging leaves on infected limbs
• Small spots of rot that enlarge quickly on affected fruits - see first photo below
• Fuzzy grey spores that cover the fruit surface
• Fruit that has shrivelled and hardened (people call them ‘mummies’) - see photo above

Thinning fruit (so they no longer touch each other), thinning leaves (to allow better ventilation) and immediate removal of affected fruit are the home-grower’s best strategies to prevent or limit Brown Rot. 

Some people recommend that you spray with copper-based fungicide when Brown Rot is detected. However, Max recommends that you don’t do this, because the leaves may well get burned and the tree may suffer. There are commercial chemicals that will control Brown Rot, but they are not recommended if you want to grow organically.

Gummosis is the name given to the oozing of sap from wounds on fruit trees. Gummosis robs a tree of nutrients. The sap hardens into gummy yellow to orange blobs on the bark. Gummosis can be the result of damage done to the trunk of the tree by you (with a mower or other garden tool), or environmental stress (lack of water or nutrients), or a fungus named Cytospora (that came in via a wound). The Cytospora fungus kills the wood underneath the wound, often causing whole branches to die. Infected wood and defoliation that may occur weakens the tree. If the disease infects the trunk, the whole tree may die.

photo 8: Gummosis

If the tree is not badly affected, you may be able to limit the impact of Gummosis by:

• Pruning away the (parts of) branches that are affected
• Improving environmental conditions (drainage, irrigation, fertiliser)
• Removing darkened areas of bark plus a strip of the healthy bark around it until the wound is surrounded by a margin of healthy bark. Then paint the wound with copper-based fungicide. Keep checking the area and repeat the bark trimming if necessary. 

Harvesting and storing ripe apricots

For best flavour allow apricots to ripen fully on the tree. Apricots are fully ripe when they feel slightly soft and the fruits separate easily from the twigs. If it is hard to pull off the tree, it isn't ripe! 

Apricots are best eaten soon after picking. If you need to store apricots, taste is best preserved if they are stored at room temperature, but this can only be done for a limited time.

Recommended further reading

The Complete Book of Fruit Growing in Australia by Louis Glowinski is an excellent book that covers a wide range of fruits and is written for Australian varieties and conditions. It has an excellent chapter on stone fruits including apricot.