Editing Olive (section)

===Growth and propagation===
[[File:Olive Grove prunings in neat rows. Ostuni, Puglia.jpg|thumb|right|Pruned trees in [[Ostuni]], Apulia, Italy|alt=Pruned trees in neat rows at [[Ostuni]], Apulia, Italy]]

Olive trees show a marked preference for [[Lime (material)|calcareous]] soils, flourishing best on [[limestone]] slopes and crags, and coastal climate conditions. They grow in any light soil, even on clay if well drained, but in rich soils, they are predisposed to disease and produce poor quality oil. (This was noted by Pliny the Elder.) Olives like hot weather and sunny positions without any shade, while temperatures below {{convert|-10|C|F}} may injure even a mature tree. They tolerate [[drought]] well because of their sturdy and extensive [[root]] systems. Olive trees can remain productive for centuries as long as they are pruned correctly and regularly.<ref>{{Cite web |date=2016-03-22 |title=On the Preservation and Maintenance of Monumental Olive Trees |url=https://www.oliveoiltimes.com/world/preservation-of-monumental-olive-trees/50921 |access-date=2025-04-17 |website=Olive Oil Times |language=en-US}}</ref>

Only a handful of olive varieties can be used to cross-pollinate. 'Pendolino' olive trees are partially self-fertile, but pollenizers are needed for a large fruit crop. Other compatible olive tree pollinators include 'Leccino' and 'Maurino'. 'Pendolino' olive trees are used extensively as pollinizers in large olive tree groves.<ref>{{Cite web |last=Marcia |title=Pendolino Olive Trees for Sale |url=https://olivesunlimited.com/portfolio-item/pendolino-olive-tree/ |access-date=2023-10-06 |website=Olives Unlimited |language=en-US}}</ref>

Olives are propagated by various methods. The preferred ways are cuttings and layers; the tree roots easily in favourable soil and throws up [[Basal shoot|sucker]]s from the stump when cut down. However, yields from trees grown from suckers or seeds are poor; they must be [[budding|budded]] or [[grafting|grafted]] onto other specimens to do well.<ref>Lewington and Parker, 114.</ref> Branches of various thickness cut into lengths around {{convert|1|m|ft|abbr=on|frac=2}} planted deeply in [[manure]]d ground soon vegetate. Shorter pieces are sometimes laid horizontally in shallow trenches and, when covered with a few centimetres of soil, rapidly throw up sucker-like shoots. In Greece, grafting the cultivated tree on the wild tree is a common practice. In Italy, embryonic buds, which form small swellings on the stems, are carefully excised and planted under the soil surface, where they soon form a vigorous shoot.{{citation needed|date=March 2023}}

The olive is also sometimes grown from seed. To facilitate [[germination]], the oily pericarp is first softened by slight rotting, or soaked in hot water or in an alkaline solution.{{citation needed|date=March 2023}}

In situations where extreme cold has damaged or killed the olive tree, the rootstock can survive and produce new shoots which in turn become new trees. In this way, olive trees can regenerate themselves. In Tuscany in 1985, a very severe frost destroyed many productive and aged olive trees and ruined many farmers' livelihoods.<ref name="Lydecker 1985 d662">{{cite news | last=Lydecker | first=Toni | title=The Italian Extra-Virgin Olive Oil Disaster | newspaper=Washington Post | date=August 18, 1985 | url=https://www.washingtonpost.com/archive/lifestyle/food/1985/08/18/the-italian-extra-virgin-olive-oil-disaster/2a00c9bc-ce00-4c99-8714-a2a7691a09d1/ | access-date=January 14, 2024}}</ref> However, new shoots appeared in the spring and, once the dead wood was removed, became the basis for new fruit-producing trees.{{citation needed|date=March 2023}}

Olives grow very slowly, and over many years, the trunk can attain a considerable diameter. [[Augustin Pyramus de Candolle|A. P. de Candolle]] recorded one exceeding {{convert|10|m|ft|abbr=on}} in girth. The trees rarely exceed {{convert|15|m|ft|abbr=on|round=5}} in height and are generally confined to much more limited dimensions by frequent pruning. Olives are very hardy and are resistant to disease and fire. Its root system is robust and capable of regenerating the tree even if the above-ground structure is destroyed. {{citation needed|date=June 2023}}

The crop from old trees is sometimes enormous, but they seldom bear well two years in succession, and in many cases, a large harvest occurs every sixth or seventh season. Where the olive is carefully cultivated, as in [[Liguria]], [[Languedoc]], and [[Provence]], the trees are regularly pruned. The pruning preserves the flower-bearing shoots of the preceding year, while keeping the tree low enough to allow the easy gathering of the fruit. The spaces between the trees are regularly fertilized.{{citation needed|date=June 2023}}

{{anchor|Pests|Diseases}}