Fruit Facts from
the
California Rare Fruit Growers, Inc.
Cherimoya
Annona cherimola Mill.
Annonaceae
Common Names: Cherimoya (U.S., Latin America), Custard Apple (U.K. and Commonwealth), Chirimoya, Chirimolla.
Related species: Ilama (Annona diversifolia), Pond Apple (A. glabra), Manrito (A. jahnii). Mountain Soursop (A. montana), Soursop (A. muricata), Soncoya (A. purpurea), Bullock's Heart (A. reticulata), Sugar Apple (Annona squamosa), Atemoya (A. cherimola x A. squamosa).
Distant affinity: Pawpaw (Asimina triloba), Biriba (Rollinia deliciosa), Wild Sweetsop (R. mucosa), Keppel Apple (Stelechocarpus burakol).
Origin:
The cherimoya is believed to be native to the inter-andean valleys of
Ecuador, Colombia and Peru. Seeds from Mexico were planted in
California (Carpinteria) in 1871.
Adaptation:
The cherimoya is subtropical or mild-temperate and will tolerate light
frosts. Young growing tips are killed at 29° F and and mature trees
are killed or severely injured at 25° F. If cherimoyas do not
receive enough chilling, the trees will go dormant slowly and then
experience delayed foliation. The amount of chilling needed is
estimated to be between 50 and 100 hours. The tree grows well in the
coastal and foothill areas of southern California, doing best at a
slight elevation, 3 to 15 miles from ocean. It is worth attempting in
sunny, south-facing, nearly frost-free locations from San Francisco Bay
Area to Lompoc, and may survive to fruit in a very few protected
Central Valley foothill locations from Chico to Arvin. Resentful of the
excessive dry heat of the interior, it is not for the desert.
Cherimoyas are not recommended for container culture.
Description
Growth Habit:
The cherimoya is a fairly fairly dense, fast-growing, evergreen tree,
briefly deciduous in California from February through April. The tree
can reach 30 feet or more, but is fairly easily restrained. Young trees
"harp," forming opposite branches as a natural espalier. These can be
trained against a surface, or pruned off to form a regular
free-standing trunk. Growth is in one long flush, beginning in April.
The roots commence as taproot, but the slow-growing root system is
rather weak, superficial, and ungreedy. Young plants need staking.
Foliage:
The attractive leaves are single and alternate, 2 to 8 inches long and
up to 4 inches wide. They are dark green on top and velvety green on
the bottom, with prominent veins. New growth is recurved, like a
fiddle-neck. Axillary buds are hidden beneath fleshy leaf petioles.
Flowers:
The fragrant flowers are borne solitary or in groups of 2 or 3 on
short, hairy stalks along the branches. They appear with new growth
flushes, continuing as new growth proceeds and on old wood until
midsummer. The flowers are made up of three fleshy, greenish-brown,
oblong, downy outer petals and three smaller, pinkish inner petals.
They are perfect but dichogamous, lasting approximately two days, and
opening in two stages, first as female flowers for approximately 36
hours. and later as male flowers. The flower has a declining
receptivity to pollen during the female stage and is unlikely to be
pollinated by its own pollen in the male stage.
Fruit:
The compound fruit is conical or somewhat heart-shaped, 4 to 8 inches
long and up to 4 inches in width, weighing on the average 5-1/2 to 18
ounces, but the largest fruits may reach 5 pounds in weight. The skin,
thin or thick, may be smooth with fingerprint-like markings or covered
with conical or rounded protuberances. The sweet, juicy, white flesh is
melting, subacid and very fragrant. The fruit is of a primitive form
with spirally arranged carpels, resembling a raspberry. Each segment of
flesh surrounds a single hard black bean-like seed. The fruit size is
generally proportional to the number of seeds within. They ripen
October to May.
Culture
Location:
Cherimoyas prefer a sunny exposure, buoyant marine air and cool nights.
In southern California do not plant where heat collects on barren
hillside or against a wall, since the leaves and fruit may sunburn
badly. In the north, do the opposite: plant against a south facing wall
to collect heat and encourage early bud-break and fruit ripening. The
trees need protection from constant ocean or Santa Ana winds which may
damage them and interfere with pollination and fruit set.
Soil:
The cherimoya performs well on a wide range of soil types from light to
heavy, but seems to do best on a well-drained, medium soil of moderate
fertility. The optimum pH ranges from 6.5 to 7.6.
Irrigation:
Cherimoyas need plenty of moisture while they are growing actively, but
should not be watered when they are dormant. The trees are susceptible
to root rot in soggy soils, especially in cool weather. Commence deep
watering biweekly in April. Drip irrigation is also an excellent way to
supply water. It is best to avoid poor water to prevent salt build-up.
Drought-stressed trees will drop their leaves, exposing the fruit to
sunburn.
Fertilization:
Cherimoyas should be fertilized on a regular basis. Apply a balanced
fertilizer, such as 8-8-8 NPK, in midwinter, then every three months.
Increase the amount of fertilizer each year until the trees begin to
bear fruit. Mature trees require an annual application of 4 ounces of
actual nitrogen per inch of trunk diameter. Cherimoyas also respond to
organic amendments. It should be kept in mind that yellow leaves may
mean that the soil too dry or the weather too cold, not always a need
for fertilizer.
Pruning:
Cherimoyas have rather brittle wood. Prune during the dormant period to
develop strong branches that can support the heavy fruit. Train the
tree to two scaffold branches at 2 feet of trunk, pruning them to a 2
foot length. Save only the strongest single shoots, preferably those at
60 to 90 degree angle, and remove the others. In the following years,
remove two-thirds of the previous year's growth, leaving six or seven
good buds, at time of new growth. This will keep fruiting wood within
reach of the ground. Thin out crossing branches.
Frost Protection:
Young trees are very frost sensitive. Wrap the trunk and scaffold with
sponge foam for protection, or cover the entire tree. In cooler areas
plant next to a south-facing wall or under the eaves to trap house heat.
Pollination:
Since natural pollinators are not present in California, the flowers
must be pollinated by hand. This is best done in mid-season of bloom,
over a period of two to three months. In early evening, collect in a
small bottle the anthers and pollen from the interior of fully open
male flowers with a #2 or #3 artists brush. Anthers will be tan colored
and the white pollen falling from them will be obvious. The pollen has
its highest viability at the time it is shed and declines significantly
with time. Immediately apply freshly collected pollen with a small
brush to the flowers in partially open, female stage. If no female
stage flowers are available, pollen may be saved in the sealed
container under refrigeration overnight. Pollen may then be applied to
female stage flowers in the morning. In large scale operations the
pollen may be mixed with inert Lycopodium spores, PVC, starch or talc
powder and applied with aspirator-type Japanese apple-pollinators, to
save time and pollen. Pollinate every two or three days, and only
flowers easily reached inside the tree, to avoid sunburned and
wind-damaged fruit. If pollination efforts are quite successful, it may
be necessary to thin the fruit. Too much fruit may result in small size
and adversely effect future yields.
Propagation:
Since there are no recognized rootstocks for cherimoyas, seedlings are
universally utilized. Seeds from the White cultivar (Dr. White) are
thought by some to produce superior rootstocks, however there does not
appear to be a great deal of objective data to support this position.
Seeds remain viable for two to three years if kept dry and protected
from weevil and fungi. With 70° F bottom heat, seed will germinate
in about 21 days, but will require about 40 days under normal ambient
growing conditions. Seedlings should be transplanted to deep containers
(approximately 18") when they are 3" tall to promote development of the
tap root. In frost-free areas, it is recommended that seedlings for
spring grafting be planted in their ultimate location in the fall and
grafted in the ground the following spring.
Grafting is most
successful in January through May provided previous years leaves have
not been shed from the potential scionwood. During this period no scion
preparation is required other than removal of leaves. All normal
grafting techniques appear to be equally successful. However in
topworking, nurse branches are desirable if not essential for success.
To bud, collect budwood in July store refrigerated for 10 days in
plastic. Petioles will drop exposing dormant buds. Bud at once using
chip bud technique and wrap well against dehydration. Grafted plants
will bear in two to three years.
Pests and Diseases:
Mealybugs and snails are the main pests of cherimoyas. Keep ducks or
apply copper strips to the trunks for control of snails. Mealybugs are
brought by ants which can be controlled to some extent by maintaining
fresh Tanglefoot on masking tape around the trunk. The masking tape is
important to prevent damage to the tree. Skirt the tree to prevent ant
access from the ground or weeds. No chemicals are registered for use on
Cherimoyas.
Cherimoyas are susceptible to Armillaria (Oak Root
Fungus) and Verticillium. Do not plant in old vegetable gardens, or
near tomatoes, eggplant or asters. Crown rot can kill trees damaged by
frost or growing in saturated soil, as well as from trunks hit by
frequent, superficial lawn sprinkling.
Harvest:
The fruit turns a pale green or creamy yellow color as they reach
maturity. Color change is not marked in cool weather. They should be
picked when still firm and allowed to soften at room temperature. Ripe
fruit will give to soft pressure. Overripe fruit will be dark brown.
Fruit left on the tree too long will usually crack or split and begin
to decay. The fruit should be clipped rather than pulled from the tree.
Cut the stem close to the fruit so it won't puncture other fruit during
storage.
Store mature fruit above 55° F to prevent chilling
injury to the skin and flesh. Ripe fruit will deteriorate quickly but
can be stored at temperatures lower than 55° F for short periods.
Ripe cherimoyas can be frozen and eaten like ice cream.
Cherimoyas
are best served chilled, cut in half or quartered and eaten with a
spoon. The fruit can also be juiced or used to make delicious sorbets
or milkshakes.
Commercial Potential:
Though unusual in appearance, cherimoyas are readily accepted by
western tastes and has become a favorite tropical fruit. Demand greatly
exceeds supply in all U.S. markets as most fruit never leaves
California, the only producing state. The fruit commands high wholesale
and retail prices, but costs are high and major crop losses from frost
and fruit splitting are an ever present possibility. The major labor
costs are pruning, pollination, ant control and irrigation.
Cultivars
Bays Origin
James Bays, Ventura, Calif., 1920. Tree broad, to 20 ft. Best in
Carpenteria area. Fruits round, medium size, light green, skin shows
fingerprint like marks (impressa type). Flavor good, almost lemony. Big Sister Origin
James Neitzel, San Diego, Calif., 1979. Sibling of Sabor. Fruit large,
very smooth, good flavor; impressa type. Often self-fruitful. Booth Origin
A. F. Booth, Hollywood, Calif., 1921. Among hardiest of cherimoya, does
well in most present growing areas. Tree 20 to 30 feet high. Fruit is
conical, impressa type, medium size, rather seedy, with flavor that
suggests papaya. Chaffey Origin
A.M. Chaffey, West Los Angeles, Calif., 1945. Seed from Salta,
Argentina. Tree rather open, fast growing. For coastal areas. Fruit
small to medium, round, impressa type, with high, lemony flavor. Ecuador Tree
broad, branches limber, spreading. Selected for superior hardiness.
Fruit medium, quite dark green, mammillated, flavor good. El Bumpo Origin
Rudy Haluza, Villa Park, Calif., 1986. Fruit conical, medium size,
mammillated, not suited for commerce. Skin soft, practically edible.
Flavor among the finest. Honeyhart
Medium, skin smooth, plated, yellowish green. Pulp has smooth
texture, excellent flavor, very juicy. Ripens November to March. Knight (syns. DV, Pierce, M&N Pierce) Origin
a Mr. Knight, Orange, Calif., 1930's. Scions imported from Mexico.
Recovered from Dr. Pierce's ranch, Goleta, in 1950's and propagated
under several names. Tree has medium vigor, medium-sized pale green
wavy leaves. Fruit has minor protuberances, a thin skin, a slightly
grainy texture and is quite sweet. Libby Origin
Rudy Haluza, Villa Park, Calif.,1986. Tree large. Fruit impressa type,
round conical; early harvest. Sweet, strong flavor. McPherson (syn. Spain) Tree
pyramidal, vigorous, to 30 ft. Fruits small to medium in size, conical,
dark green, impressa type, not seedy. Flavor suggests banana, sweetness
varies with temperature while maturing. Nata Origin
George Emerich, Fallbrook, Calif., 1983. From Ecuadorian seed. Tree
vigorous, bears quickly, flowers profuse, tendency to self-pollinating.
Fruits smooth, light green, conical, 1-1/2 to 2-1/2 pounds. Skin thin,
tender. Flavor has good sweet-acid balance. Ott Origin
William Ott, La Habra Heights, Calif., 1936. Plant patent #656. Seed
from Mexico, D.F. Tree strong growing. Fruit medium, heart shaped
tuberculate, flesh yellow, seedy, very sweet. Matures early. Pierce (syns. Knight, Escondido White, Ryerson, Thomson-Spain, & Bayott) Believed
to be from a group of scions imported from Mexico in the 1930's by a
Mr. Knight of Orange. Dr. H. F. Pierce planted a grove in Goleta in
that period made up largely of trees produced by Knight. This cultivar
was Dr. Pierce's favorite and was named "Pierce" by him. Tree is
vigorous with large dark green leaves. Fruit is medium sized elongated
conically shaped with very smooth skin and a high sugar content. Sabor Origin
James Neitzel, San Diego, Calif., 1979. Sibling of "Big Sister". Fruit
mammillated, varies in size, not usually large. Among the best in
flavor. Whaley Origin
Hollywood, Calif., 1924. Tree moderately vigorous. Fruit medium to
large elongated conical, tuberculate, light green, flavor good. Seed
enclosed in an obtrusive sac of flesh. White (syn. Dr.White) Origin
J. H. MacPherson, Lemon Grove, Calif., 1928. Tree open, unkempt; to 35
feet, needs forming. A commercial favorite at Carpinteria. Best near
coast. Fruit large, to 4 pounds, conical, with superficial small lumps
(umbonate). Flesh juicy, flavor weak, suggesting mango-papaya.
Further Reading California Avocado Society Yearbook, 1947 pp 67-70. Morton, Julia F. Fruits of Warm Climates. Creative Resources Systems, Inc. 1987. pp. 65-69. Ortho Books. All About Citrus and Subtropical Fruits. Chevron Chemical Co. 1985. pp. 23-25. Popenoe, Wilson. Manual Of Tropical And Subtropical Fruits. Hafner Press. 1974. Facsimile of the 1920 edition. pp. 161-177. Sanewski, G. M. Growing Custard Apples, Brisbane, Queensland Department of Primary Industries, Horticulture Branch, 1987. Smithsonian Institution, U.S. National Herbarium Contributions, Vol. 18 (1927).
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© 1996, California Rare Fruit Growers, Inc.
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