Portugal is renowned for its oranges, and some countries have used their version of the word Portugal to name their orange fruit, such as Romania (portocálâ) and Greece (portukáli). The conditions in the Algarve region are perfect – the soil, sun in plenty and pretty much no frost, with over 80 percent of the Portuguese orange groves being located here. But why don’t most have seeds, why do some look different, and why do we seem to have oranges ready for picking all year round (which is probably clever planting techniques of the different types).

Seedless - So, the technical stuff of being seedless. They are not an example of GM crops modified through bio-engineering. Apparently they occurred naturally in a single mutated tree, discovered by farmers in a Brazilian orange grove in the 1870s. Cuttings were sent to the USDA which propagated the trees through grafting and rooting practices, starting the seedless navel orange boom. And here’s a word you probably never knew – parthenocarpy. In simple terms it’s the development of fruit without fertilization of the ovules and, therefore, without seed development.

Grafting - all commercially available citrus trees are grafted or budded to speed up the process of harvesting fruit and to increase disease resistance through using a hardier rootstock. Grafting takes the roots of one plant, called the stock, and fuses onto it the shoot of another plant, called the scion. In general, grafted orange trees start to produce fruits at their 3rd or 4th year of age, with their most productive period being between 10 and 40 years old. The average healthy and mature orange tree produces 200-350 oranges. However, experienced orange farmers after years of practice can probably double that.

Types of oranges

Credits: PA; Author: PA;

One of the most popular of the oranges is the Navel Orange. When it is peeled, there is a partially formed, undeveloped conjoined ‘twin’ fruit on the blossom end and is named because it looks like, well, a human belly button, or navel. It's naturally seedless; any new trees must be grown from cuttings of old trees. The harvesting starts in November and can last until March.

The Valencia Late Orange is harvested during the months of June to September and is medium to large in size, with a spherical oblong shape. It has no navel, has very few pips, is very bright in colour, with peel slightly thick and smooth. Their season usually begins around April and they can remain on the tree until summer, late June or more, depending on the season’s weather.

The Newhall Orange is one genus that is harvested between November till late January/early February, and has an oval shape, is medium to large in size, has a small navel, with smooth peel and an intense orange colour. Sweet and seedless.

The Lane Late Orange is harvested between February and May, and is medium to large in size, although slightly smaller than the Newhall, round in shape, has no pips and has a small navel, barely visible externally.

The Rhode Orange is harvested between the months of March and May. Is medium to large in size, has no pips and has a small navel, visible externally.

Whats the difference between tangerines, mandarins and clementines?

Tangerines and clementines are two varieties of mandarins. They're both prized for their sweet flavour and soft, easy to peel skins. Of the two, clementines are sweeter and easiest to peel. The clementine is a tangor, a citrus fruit hybrid between a willowleaf mandarin orange and a sweet orange, named in honour of Clément Rodier, a French missionary who first discovered and propagated the cultivar in Algeria. The exterior is a deep orange colour with a smooth, glossy appearance, and is harvested around late October – February.

Credits: Unsplash; Author: Uliana Kopanytsia;

An oddity is the Blood Orange, which isn’t grown here. The pigments that provide the ‘blood’ colour do not appear unless they are exposed to cooler weather during development or post harvest, but continue to thrive in Italy, Spain and Malta. California produces the majority of the U.S. crop. There are three main types of blood oranges: moro, tarocco and sanguinello.


Marilyn writes regularly for The Portugal News, and has lived in the Algarve for some years. A dog-lover, she has lived in Ireland, UK, Bermuda and the Isle of Man. 

Marilyn Sheridan