The Cashew and You
BY RICHARD J. CAMPBELL
FAIRCHILD TROPICAL BOTANIC GARDEN
As published in the Miami Herald
Most everyone is familiar with the cashew; among the most
delicious and expensive of the nuts available in our supermarkets. However,
most are unaware of the other parts of the cashew plant that we can grow and
enjoy. Further, the world of the cashew has changed in the last decades and it
is now feasible to grow, fruit and enjoy the cashew in South
Florida.
The cashew is in the mango family and is native to Brazil. It is a
commercial nut crop in its home country and in many of the dry tropical zones
around the world. New selections have been made in Brazil andIndia that are
dwarf, productive and add a new dynamic to the venerable cashew. Today one will
not find only cashew nuts, but increasingly the cashew “apple” is becoming a
more popular product around the globe.
The cashew apple sits just above the nut at the ends of the
branches. The cashew apple can be red, yellow or green and many shades in
between. They have a striking beauty on and off the tree given their waxy skin
and uniform bell shape. Cashew apples were historically astringent until fully
ripe. Anyone who has bitten into an unripe cashew apple of old will not soon
forget, but in the last decades new non-astringent selections have been made
that have expanded the potential for the cashew apple as a fresh fruit. Today
you can find modern non-astringent cashew apples in the supermarkets of Brazil, Central America and Africa.
And, what does all this mean to the South
Florida homeowner? Simply, now we have access to good quality
selections of cashew that can be successfully grown and fruited in the home
garden. The tree is a beautiful ornamental in itself, with shiny dark green
leaves and a pleasing structure. The good selections of cashew sold today in
reputable nurseries of South Florida are mostly
dwarf selections that will begin to flower and fruit at less than 2 years of
age. You should ask the nurseryman to be sure. The dwarf cashew is a sight to
behold, highly productive and selected for good cashew apple quality. They are
so small in fact that they can be successfully grown in containers.
The cashew tree does not require it, but will thrive in acid
soils. Unfortunately, south of Broward County we few areas of
acid soils, so mulching to amend our poor native soils is a good idea for
optimal tree growth. Trees should be placed in the full sun, although a high
canopy of trees will provide an added degree of protection from cold damage. A
cashew tree with light shading will still perform well, growing and fruiting at
a reduced rate, but having a better overall appearance and better survival
during freezes.
The cashew is a fast grower in the warm months and will
begin to flower usually before the second year of planting. Cold temperatures
and low humidity winds in the winter and spring will damage the tree. The
cashew can withstand temperatures down to freezing, but if there is frost the
tree will sustain considerable damage. Following a severe cold spell the cashew
will lose much of its foliage unless well protected. Young trees will be lost to
cold winter temperatures and should be protected in the first years of
planting.
Fertilization should be made two to three times per year
during the active growing season. The bests months are May, June and September.
Do not fertilize later than September, as this can increase the vigor of the
tree in the winter and make the tree more susceptible to cold damage. Remember
that even when protected the cashew tree will have leaf browning and drop
during the winter months. Fall and winter fertilization will only worsen the
trees response.
The tree is in the mango family and suffers from the same
anthracnose disease that causes the black spots on mango fruit. In cashew the
anthracnose damages the blooms and can cause crop loss in the warm and humid
months. In general it is best to keep your cashew tree as dry as possible. They
should not be irrigated in the home landscape. If they are irrigated the tree
may grow well, but the fruiting will suffer.
The dwarf varieties will require almost no pruning, save a little
bit of shaping following the crop. The fruiting is typically in the early
summer and can spread over several months. The cashew apple can be harvested
when they are fully colored on the tree. If they are non-astringent they can be
eaten while still firm, but it they are a standard selection they must be left
to fully ripen before eating.
The cashew apple is eaten fresh and is also one of the most
refreshing juices among any fruit. The flavor is reminiscent of mango, with an
intense sweetness and slight tart bite. All colors of cashew apples can be
eaten and there is little flavor difference among the colors. The nut of your
cashew tree is more problematic. The cashew, being a member of the mango
family, has irritating latex that can cause severe rashes and allergic
reactions. The latex occurs throughout the plant, but the highest concentration
is in the shell of the raw nut. You must use caution in handling the raw shells
and the raw nuts themselves also contain some irritating latex, but to a lesser
extent. Before the nuts are eaten they should be roasted. Most people will not
go the lengths needed to produce their own cashew nuts, sticking instead with
the beautiful and tasty cashew apple.
The cashew apple is a legitimate tree for planting in
the home garden. If we have heavy frosts during the winter you may lose your
tree, but in warm times the cashew will grow well and with the new selections,
provide you with tasty non-astringent cashew apples. And who knows, with
climate change we may all be growing cashews for our homes.