April Plant of the Month: Prunus armeniaca – Apricot

No plant genus signifies the coming of spring more regally than Prunus. Thanks to plant hunters such as E.H. Wilson, and the generosity of the Government of Japan, many American cities glow with the blossoms of cherry trees in early spring.

While I have nothing against the showy, prolific blooms of Prunus x yedoensis (Yoshino cherry) that dominate the Tidal Basin in Washington, D.C. I prefer Prunus armeniaca as the finest Prunus of them all. Commonly called Apricot, this ‘cherry’ blooms early, prolifically and reliably AND, if sited properly, produces a delicious fruit that is easy to grow organically here in the Northeastern United States.

Unfortunately, Prunus as a group is riddled with insect and disease problems and often are not long lived. So enjoy them while they are in full vigor.

The apricot originated in northeastern China near the Russian border (in the Great Wall area) not Armenia as the name suggests. Cultivation in China dates back 3000 years, and movement to Armenia, then to Europe from there, was slow; the Romans introduced apricots to Europe in 70-60 BC through Greece and Italy. Apricots probably moved to the US through English settlers on the East Coast, and Spanish Missionaries in California.

Today, apricots are grown commercially almost exclusively in California. But they are well suited for the home landscape in many regions of the U.S.

For much of their history of cultivation, apricots were grown from seedlings, and little selection took place until the nineteenth century. Today apricots are grafted onto rootstocks compatible with regional soil types and cold hardiness zones. Choose dwarf and semi-dwarf selections for ease of picking fruit and to ensure that trees do not get too large for smaller landscapes.
Apricot trees are sensitive to climatic conditions and require the best possible growing sites to remain healthy and regularly productive. Apricots blossom about a week earlier than peaches. Therefore, plant apricots only on sites which are not susceptible to frequent or late spring frosts. Favorable sites for delaying spring bud development include: areas elevated above surrounding low lying valleys; close proximity to a large body of water; northern or eastern exposure.

Soils must be well drained and preferably of a sandy type. Poor subsoils of any kind will result in the death or poor growth of many trees. Avoid heavy, poorly drained soils.

Do not use apricot trees grafted on peach seedlings. Manchurian apricot seedlings and seedlings of the Michigan apricot selection, Goldcot, are compatible with apricot varieties. The Manchurian seedlings are thought to be especially winter hardy. The cultivars Goldcot, Moongold, Sungold and Moorpark are reliably hardy in my experience here in the northeast. Goldcot is apparently completely self-fruitful and can be planted alone. The other varieties, while ordinarily self-fruitful, will set heavier crops when unfavorable weather prevails during blossoming periods if they are inter-planted with other fertile varieties.
Fall-planted trees are more subject to cold injury during the first winter after planting. Plant the bud union 4 inches below ground level for good anchorage. The soil should be well settled and firm around the roots.

Locating sizeable fruit-bearing trees is always difficult. Apricots are best purchased via specialty or mail order sources. Train the young tree to the modified central-leader system. Select two main scaffolds on opposite sides of the trunk, well separated so they will not touch each other when fully grown. The first scaffold should be about 30 inches above the ground if trees are to be mechanically harvested. The second scaffold should be 8 to 10 inches above the first. Select scaffolds having wide angles at the point of attachment with the trunk. Sharp-angled branches split badly. The leader must be left longer than the scaffolds so that it will not be shaded out.
It is very important the second spring to remove all excess scaffolds from the trunk, retaining just two or three. Head the scaffolds back somewhat if they are likely to grow higher than the leader. By the third and fourth years, the trees are beginning to produce some fruit. The main framework of the tree has been established, and pruning is mostly to remove additional branches that may come from the trunk, and to head back new terminal growth if it exceeds 2 feet in length. A small amount of thinning out may be necessary where branches are too thick or are rubbing. Do not leave too many branches originating close together on the trunk.

The apricot produces most of its fruit on rather short- lived spurs. Prune mature trees to remove branches loaded with old spurs and keep the trees producing good replacement wood. This requires a combination of thinning out branches having many weak spurs and heading back long branches by one-third or to a strong lateral branch. Mature trees must make from 16 to 24 inches of new terminal growth a year to maintain satisfactory annual production. If less growth is made, the trees will fall into a biennial bearing habit and produce a large crop of small apricots every other year. Prune or head back the long branches in April. Additional pruning in June and August will reduce excess vigor. Do not prune during late fall or mid-winter because of drying out and the possibility of winter injury.

Grow young apricot trees slowly. They have a tendency to make excessive growth, rendering them more susceptible to winter injury. New growth should not exceed 2 feet in length annually.
If fruit set is heavy, thin the individual fruits so that they will be 1 1/2 to 2 inches apart. Otherwise, fruits will be small, and the trees will become biennial in bearing habit. Thinning can be done by hand, or — faster and easier — by careful pole thinning. The excess fruits may be removed by rubbing and tapping. Avoid hard blows, as all of the fruits will be knocked off for a considerable distance from the point of contact. Early thinning is recommended. Start thinning as soon as danger of frost has passed. Of course the real treat is reaping the harvest of fruit that typically ripens in early July here in Rhode Island, before the real onset of hot humid conditions that can saddle many other later bearing fruiting plants with problematic insect and disease problems.

Once established, Prunus armeniaca holds up well to hot, dry conditions. Typically maturing at heights varying between 8 – 20’ tall, with a similar spread, but often with variable form, Prunus armeniaca is an excellent choice as a specimen tree for small properties, within a lawn setting, as an accent plant, and within mini grove like settings. Its reddish-cinnamon colored bark stands out prominently against a snowy backdrop. Hardy zones 4-9