Green Man Publishing

Apricot

Prunus armeniaca

Introduction

The apricot originated in China or Manchuria, but is now grown in warm temperate areas around the world. A fully ripened apricot doesn’t ship well, so for the best flavor you have to grow them yourself.

About Apricot

Ease of growing: Moderate

Hours of winter chill 350-900

Size Standard – 20-30ft tall x 20-30 ft wide

Semi-dwarf – 12 – 15ft tall

Dwarf – 4 – 8ft tall

Zone 5 – 9

Blooming period: Early spring Feb-March

Fruiting period: July-Aug

Life expectancy: 75 years (shorter in many areas)

Bearing age: 3-4 years

Days to harvest: 100-120

Yield: Standard – 3 to 4 bushels

        Dwarf – 1 to 2 bushels.

Nutrients

The fruit is rich in sugar, vitamins A and C, riboflavin (B2) and niacin (B3) as well as the minerals calcium, phosphorus and iron. It also contains lycopene. The seed is rich in protein and fat, but most types also contain cyanide, which is poisonous. The exception to this are the sweet pit apricots, which are actually grown for their edible seeds as much as their fruit.

Climate

The apricot is somewhat more demanding in its requirements than most common tree fruit (though these are similar to Cherry) and so is less commonly grown. The perfect climate for apricots has:

Moderately cold winters (it is hardy down to zero F) which provide enough chill to break dormancy,

Mild springs without late frosts (the flowers appear early- before peach and are easily damaged by frost).

Warm (it suffers if it gets too hot), dry summers to ripen its fruit to perfection.

Low humidity. In areas with high humidity it is often afflicted by pests and diseases, so it is mostly cultivated commercially in the warmer, drier western areas. However it can be grown in other areas if you choose the right microclimate and the right variety.

Site

Apricots like the same growing conditions as their relatives the peaches. They flower very early in the year and so the blossom is vulnerable to damage by frost (which of course means no crop that year). In cold climates they should always go in the warmest part of the garden (never in a frost pocket), such as high up on a slope or hill, where cold air doesn’t settle. They are sometimes put on a cool north or east facing slope (or north side of a building) so the trees will stay dormant longer and flowering will be delayed. Some of the newer varieties naturally blossom later and are good for colder areas. The trees should always be sheltered from strong and cold winds as these can interfere with the activities of pollinating insects.

Apricots produce better in full sun, but in hot climates they will tolerate some shade, though they. In areas with cool summers they are sometimes grown as an espalier against a south or west facing wall (where they will get additional warmth). They need good air circulation to minimize disease problems however. In areas with very cold winters dwarf varieties can be grown in containers and brought into a greenhouse for the winter.

Soil

pH 6.5 – 8.0

Apricots can do well in most soil types, so long as they are well drained, but the ideal soil is light, deep, moisture retentive and fairly fertile. They don’t mid fairly alkaline soil, but don’t like sandy, saline or heavy clay (it tends to get too wet in winter) soils. If your soil isn’t well drained you should consider planting on a hillside, or on a mound.

Soil preparation: If the soil isn’t very fertile you should prepare the whole growing area (not just the planting hole) by single digging (or even double digging if the soil is heavy or very poor). This enables you to incorporate organic matter deeply into the soil (4” of compost or aged manure) along with various amendments. This works much better than simply amending the planting hole, as it encourages the trees roots to spread out in all directions.

Spacing:

A standard apricot doesn’t get to be very big, usually not much more than 25-30 feet in height, and dwarf trees may only be 6 feet tall. It is quite a vigorous tree though and is often as wide as it is tall.

Standard trees are usually spaced 25-30 ft apart, semi-dwarfs go 12-15ft apart and dwarfs may be as little as 8-10 ft apart.

Care of plants before planting: When you get your plants home it is best to get them into the ground as soon as possible. If this isn’t possible then you should heel them in, which means placing them in a trench and covering the roots with soil. If you buy plants mail order you should unwrap them as soon as they arrive and soak the roots in water overnight, before planting (or heeling in).

Planting

Apricots are most often planted as 1-2 year old bare root trees. Where I live these are available from mid January to early March for immediate planting. In colder climates they are usually available in early spring. Mail order trees are available for an even longer period because they are kept in cold storage until shipped.

When: Bare root trees are usually planted in early spring in cold climates and from late fall to early spring in mild-winter areas. Plants in containers can be planted at any time of year, but are more expensive and don’t usually do as well (sometimes they are simply left over bare root stock that has been potted up).

How: Dig a hole for the tree 2‑3 times as wide as the root ball and the same depth, to give the roots plenty of space. A tree should be set in the ground at the same depth it was growing in the nursery (this is most easily measured by laying a stick across the hole to get the right height). In poorly drained soils you may have to plant on a mound, to keep the collar of the tree from possibly rotting in wet soil.

Start planting by throwing a couple of shovels of soil (and possibly organic matter) in a mound in the bottom of the hole. You then hold the plant over the mound and spread out the roots evenly over it. Put some soil in the hole to anchor the tree in place and firm it down. You might want to add some rock phosphate to the soil as you re‑fill the hole. Fill up the hole with the rest of the soil, making sure the tree stays vertical. When you have finished there should be a slight mound, so as the soil settles it becomes flat (rather than sinking to form a depression where water might collect). You then water generously, not only to give water to the plant, but also to help establish contact between roots and soil. The final step is to spread out a mulch, to conserve water and keep down weed competition. It is also a good idea to put a permanent label on the tree with the variety and rootstock (also write this down in a garden journal).

The newly planted tree may then have its branches trimmed back by a third to encourage new growth (but only if this hasn’t already been done in the nursery, don’t do it twice!)

Staking: Newly planted trees were once routinely staked, but it is now thought that trees develop a strong trunk more rapidly if not staked. Staking may be necessary on very windy sites though (although you should avoid these if possible).

Maintenance: Apricot is fairly straightforward to grow if you give it the right conditions. The biggest problems are damage to the flowers from late frost and various diseases.

Watering: Apricots originated in an area with little summer rainfall and so are fairly drought tolerant However the size of harvest will increase if you give them an occasional deep watering (ideally this should penetrate down 3 ft). This is most critical when the fruit are sizing up (and are ½” – 3/4” in diameter). Lack of water can cause fruit to drop or split and seeds to crack. Flower buds start to differentiate in late summer so it is important they get enough water (and nutrients) at this time. Don’t over-water though as this can cause root rot.

Of course all newly planted trees need regular watering until they are established (at least for one summer). Trees planted against walls are particularly vulnerable to dry soil and should be kept sufficiently watered.

Mulch: Use a mulch of compost or aged manure to keep the ground around the roots moist and to add nutrients.

Fertilizing:

Apricots have a vigorous and wide spreading root network that can search for nutrients very efficiently. They need a good supply of nitrogen, as well as phosphorus and potassium. This should be supplied in spring so it is immediately available and doesn’t get washed out by winter rains. Later applications may encourage vigorous late growth which may be vulnerable to frost damage. They also like zinc, calcium, boron and copper. You might also add lime occasionally to supply calcium and keep the pH up.

Pollination: The insect pollinated flowers have both male and female parts and most apricot varieties are self-fertile. Some varieties need cross-pollination though and for heaviest crops they all benefit from it. As I mentioned previously they flower early in the year (late winter to early spring) and are vulnerable to late frost. In extreme situations it is possible to protect the blossom of dwarf trees by covering the tree with sheets (these shouldn’t touch the flowers). This early flowering may also mean that pollinating insects aren’t very active, which can be a problem if the flowers don’t get properly pollinated. Pampered espaliered trees are sometimes hand pollinated, using a small paintbrush to take pollen from one flower and apply to another. This isn’t very practical on a full sized standard tree though.

Thinning: If all goes well the trees can set a lot of fruit and if you want to get large fruit you will have to thin. If you neglect thinning you will get a lot of very small fruit (which may be okay too). Start thinning while the fruit is still small (1/2”-1”), though wait until after natural fruit drop. Gardeners with too much time on their hands sometimes thin gradually, going in several times, though this seems like making work for yourself. Start thinning by removing small, damaged or otherwise inferior fruit, removing those that are in the wrong place and thinning clusters to one fruit each. The ultimate aim is to have a single fruit every 2-4”. Always leave the biggest and best fruit of course.

Pruning:

When: Apricots are often pruned in winter or early spring while they are dormant, but in areas with potential disease problems it’s better to prune in late spring (after fruit is set) or early summer. Wounds heal faster at this time, which can help to avoid diseases such as Bacterial canker, Silver leaf or Die-back.

How: Apricots are pruned in the same way as peaches but aren’t quite as vigorous. Copy that here. The best flowers and fruit are produced on the spurs of 2-3 year old wood and you prune to encourage the development of new fruit bearing shoots. Apricots aren’t usually pruned very vigorously as it increases vegetative growth and reduces fruit bearing. Generally you prune to provide good air and light penetration and to remove dead, diseased and crossed branches, watersprouts and any suckers that emerge from the roots.

Training: In hospitable apricots are often grown with an open center (vase shape), but in colder areas a central leader is probably better. Prune as little as possible in the first couple of years so the tree can produce fruit bearing spurs

Special shapes – These are mostly used if you have limited space or want to plant against a wall for extra heat, though they are sometimes also used for ornamental purposes (they do look beautiful.) Espaliers, fans, dwarf pyramids and cordons are all interesting and can work well if you have the time and inclination to look after them. In my view they require extra work for less fruit and so I would avoid them unless there was no other way to grow apricots.

Propagation: Apricots are easily raised from seed and the trees will usually produce good fruit (in about 5 years). Save seeds from the fruit you eat and either stratify them (for 2-3 months) or simply plant outdoors in fall (these must be protected from rodents or they may disappear). I have grown producing trees from seed and they were pretty good. Interestingly the seedlings I grew were quite thorny when young (no doubt to protect them from predators) but grew out of it as they got bigger.

Apparently it is also possible (with some difficulty) to root cuttings of half-ripe wood with a heel, in late summer, or use softwood cuttings in late spring. Branches can also be layered in spring (if you can get one to the ground).

Containers: Dwarf apricots do quite well in a container, though they won’t be hugely productive (the genetic dwarf varieties work well for this). In very cold climates apricots are sometimes grown in containers so they can be taken indoors for the winter.

Pests:

A number of pests can attack apricots, but a mature tree is able to tolerate most minor insect damage without harm. A spray of dormant oil in early spring is used to combat many pests.

Spider mites

Scale insects

Aphids

Codling moth

Peachtree and Dogwood borers – The larvae of these insects tunnel into the cambium and can kill branches and young trees. They may also weaken older trees.

Plum curculio (east of Rocky Mountains).

Squirrels will go for sweet-pit apricots (Harcot and Precious).

Birds peck at the almost ripe fruit.

Wasps may start to eat the fruit as it approaches ripeness.

Nematodes

Disease:

In areas with high humidity Apricot is often afflicted by disease, either serious or otherwise. Remove fallen fruit and any diseased leaves from underneath the trees to minimize re-infection.

Dieback (Blossom Wilt) Eutypa?)

Silver leaf

Brown rot: This attacks fruit and enters through wounds in skin and can be a major problem in humid climates.

Bacterial spot

Bacterial gummosis

Blossom blight

Coryneum blight

Water spot (fungus)

Bacterial canker: Usually affects trees that have been pruned in winter.

Problems:

Fluctuating winter temperatures: Some apricots don’t need a lot of winter chill and a spell of warm weather can start to wake up the flower buds. If this happens a return to cold weather may damage or kill them.

Harvest:

When: The fruit ripen in 100-120 days, which makes it the first of the common tree fruits to ripen (usually/ early July in my garden, but August in cooler areas). The harvest season is relatively short as they all ripen in 2 or 3 weeks. This can be a problem if you happen to go on vacation for a couple of weeks at the critical time. You could miss them.

How: You can start picking the fruit a few days after they have colored up and stopped swelling. The flavor still develops for a while after they reach full size, but pests may start harvesting earlier (and force you to do so too). A slightly underripe fruit can still be pretty good, especially for cooking and will slowly ripen after picking. The ripe fruit will be slightly soft and the skin gives slightly if pressed. Ripe fruit is easily damaged, so be very gentle with it.

Storage: You will get a lot of fruit all at once so you need a way to store the surplus. Fortunately they dry, freeze and can well.

Fresh apricots can be kept at room temperature for a week or so, slightly longer in the fridge. Freezing also works well, just slice in half to remove the pits and freeze in a plastic bag (a little lemon juice will help them retain their natural color). These should last for 6 months.

Dry apricots by cutting them in half, remove the pits and dry them until they are leathery. A dehydrator works well, though you can also dry them in the sun. They can then be stored at room temperature or in the fridge (for 6 months).

Unusual growing methods: In cool climates Apricots can be given extra heat by training them along a south or west facing wall, as espaliers or fans. They need a sizeable wall though, as they can get quite big (15 ft long x 8 ft tall is a minimum and more vigorous trees may need 20 ft x 9 ft.)

Landscape uses: Apricot is one of the prettiest common fruit trees and the white or pink blossom is quite spectacular. 

Food uses: It’s hard to get good apricots in stores because they don’t ship well. This is no doubt the reason that apricots are more popular dried than fresh. The small (average 2”) fruit is good cooked, fresh or dried (one of the best dried fruit in my opinion). Some varieties produce edible sweet seeds also.

Rootstocks: There aren’t very good dwarfing rootstocks for apricot though there are genetic dwarfs.

Seedling (Manchurian is good)

St Julian A 10-12 ft tall x 12ft wide Yield – 50lb This isn’t a good rootstock for apricots.

Lovell

Citation

Marianna 26-24 Good for heavy wet soil

Nemaguard

Krymsk 86 Similar to Lovell Tolerates heavy wet soil

Pixy 8-10ft tall x 10ft wide Yield 20lb

Brompton 15ft tall x 15 ft wide Yield 55lb+

Varieties

Several factors can make growing apricots tricky (lack of chill, late frost, fluctuating winter temperature, rainfall, pests and disease) and it is very important (even more than with most crops) to choose the right variety for your climate. There is considerable variation in tolerance and resistance in the different cultivars and this can determine whether they do well. If you live in a place with many spring frosts, you will want to choose a variety developed for northern areas that flower later, so they escape frost damage. You may also choose varieties that are resistant to brown rot or other diseases.

If you have several trees you may want to stagger the harvest season with early, mid and late varieties.

There are quite a few Apricot cultivars in existence, but only a few are widely available, and you may have difficulty finding some of the rarer varieties. A few have edible seeds as well as flesh and are known as Sweet Pit Apricots.

If you have room for several trees then you should have early, midseason and late blooming varieties to extend the harvest.

Moorpark

Blenheim

Some genetic dwarf varieties are available on their own roots. These include

Stark Golden Glo

Garden Annie

Sweet pit Apricots

These are priced as much for their edible seed than for the fruit.

Mormon ?

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