Olive Tree Selection
 

Introduction:  Little is known about olive tree (Olea europaea) cultivation in Florida.  Although olives have been grown in the state since at least the 1700s and perhaps before; very little scientifically reliable information is available. Nevertheless, because our climate and soils are somewhat similar to the Mediterranean region, olives and olive oil are currently produced in Florida, albeit in small quantities.


What variety to plant:  After selecting a proper place to plant (full sun, well-drained soils) the next step will be to determine what kind of olives you prefer to grow.  There are thousands of varieties of olive trees and many have very distinct characteristics which you might find pleasing, or not.  A fundamental decision is whether to cultivate an “eating” olive or an olive primarily used to produce oil, or both.   Since some olive trees are not self-pollinating, so the additional of a supporting variety will significantly enhance your chances of producing olives.  In that event, you might select a variety suitable as table olive as well as a few trees for oil.  Below find some choices and their characteristics.  Much of this information is provided by Bruce Golino, an experienced California olive nurseryman.


                              Some Varieties for Consideration


    Arbequina (Spain)Arbequina is probably the most popular olive tree grown in Florida at this time.  It is a fast grower and self-pollinating (but benefits greatly from co-planting with other cultivars such as Arbosona and Koroneiki).  The fruit (drupe) is small and not generally favored as a “table” olive but the oil is mild, buttery and very flavorful.  It appears as a tree of medium vigor with a weeping shape.  Arbequina is tolerant to cold, salinity and high atmospheric moisture and moderately tolerant to drought and Pseudomonas savastanoi (olive knot).  It is poorly tolerant to olive fly, iron chlorosis, nematodes, scale and verticillium wilt.


    The yield of oil from Arbequina is good (20-22%), of excellent quality  and with good organoleptic characteristics. Synonyms of this cultivar include: ‘Arbequin’, ‘Alberchina’, ‘Catalana, ‘Blancal’, ‘Oliva de Arbela’, ‘Manglot’, ‘Blancas’ and ‘Oliva de Borjas’. The cultivar is distributed throughout Spain, Algeria, Argentina, Australia, Bolivia, Brazil, Chile, China, France, Israel, Peru and the USA. The tree’s requirements for chilling time are lower than some varieties and therefore is attractive in southern areas with /mild winters.


    Koroneiki (Greece):  Often planted as a “pollinator” to support pollination of the Arbequina, Koroneiki is a tree of medium vigor with a spreading habitat and open canopy. Other names of this cultivar are ‘Psilolia’, ‘Lianolia’ or ‘Korani’. It is widespread in the main olive-producing districts of Greece (i.e. Crete, Peloponnese, etc.) and is expanding in other areas of the world. In recent years this cultivar has started to be grown in the form of super-dense plantings all over the world (e.g. Australia, Italy, Spain).

    The leaves are thick, with a small leaf blade. The length of the blade is 4.5–5.2 cm and the ratio of length:width is 4.2–5.5:1.The fruit is very small (0.5 g), with a mastoid shape and ending in a teat. The fruit ripens from mid to late season and turns black at full ripening. The pit is small and cylindroconical in shape. The oil content is 27% and is high in oleic acid and is very stable.

    The ratio of flesh:pit is 1.63–4.06:1. The medium yield per mature tree is 50–60 kg. This cultivar is resistant to water stress and wind, but sensitive to Dacus oleae, Euphyllura olivina, Pseudomonas savastanoi and attacks from rhynchites. Its tolerance to cold is low and its rooting ability from leafy cuttings is constant and medium.


    Arbosona (Spain):  Arbosona is often used to support pollination (productivity) when paired with Arbequina.  One approach is to sow a few Arbosona in among the Arbequina when the grove is planted.  Arbosona matures 2 weeks later than Arbequina and has 25% less vigor.  As well, it is more sensitive to water stress and presents more vigorous regrowth after pruning. The oil of ‘Arbosona’ is more bitter to the taste than that of ‘Arbequina’, which has a fruity and pleasant flavor. Arbosona is characterized by high productivity and resistance to low temperatures, leaf drop and olive knot (Pseudomonas savastanoi).


    The clone is propagated asexually and it produces 19–20% olive oil. The Arbosana’s leaves are small in size, 58–70 mm in length and 11–12 mm in width. The color of the upper surface is green and that of the lower surface chrysolite green. The petiole is short, 5 mm. The fruit matures early, usually by the fourth week of October and is elliptical in shape. Composition of the oil is: palmitic acid (C 16:0), 1.3%; esteric acid (C 18:0), 2.0%; oleic acid (C 18:1), 74%; linoleic acid (C 18:2), 7.66%; polyphenols K225 (bitterness), 0.24%. The stability of this oil is 13.5 h at 120°C.  While Arbosona is a popular cultivar and is often planted along with Arbequina to supplement pollination in high density commercial groves, it sometimes struggles in some areas of Florida.


Other Varieties:

    Some other varieties having success in Florida include:  Ascolano, Taggiasca, Sevillano, Manzanilla, Leccino, Coratina, Empeltre, Piqual, Frantoio, Grignan, Pendolino and Chemlali.  However, these varieties have been limited to specific areas of Florida.  For example, Ascolano and Sevillano have been successful in northern Florida but not tested south of Gainesville.  Other varieties such as Barnea, a cultivar more suited to arid regions, has had mixed results. 


    Current research by the Florida Olive Council includes all the above varieties (and a few others) in tests as far south as the Orlando area.  We will have more detailed results on these tests within three years (2017).  The Council welcomes any additional information from Florida olive growers.