Introduction
Olive trees are a staple crop of the Mediterranean region and have been cultivated for thousands of years.
Olive tree growth and fruiting stages can be challenging, especially for new growers who may struggle with identifying the different phases and providing the right care at each stage.
Understanding the typical growth cycles and stages of fruit production is key for caring for olive orchards.
This knowledge helps growers know when and how to prune, fertilize, irrigate and harvest for maximum yields.
Nursery Stage
When olive trees are first grown, they spend their early years in a nursery. During this stage, the trees put most of their energy into developing a strong root system.
Growth above ground is slow, typically just several inches per year.
Nursery trees require regular watering, light pruning to develop a sturdy structure, and occasional applications of balanced fertilizer. They remain in nursery beds for their first 2–4 years.
Olive Tree Growth Stages
Young Tree Stage
After being transplanted from the nursery to their permanent growing location, olive trees enter a period of adjustment and establishment.
During the young tree stage, growth above ground increases to 1-2 feet per year as the roots expand into the surrounding soil.
Regular irrigation and mulching are important while the roots establish themselves to avoid drought stress. Light annual pruning also helps the tree develop properly. This youthful growth period typically lasts 3-5 years.
Mature Tree Stage
Once past the establishment phase, olive trees enter their mature growth stage. At this point, trees may reach heights of up to 30–40 feet with spreading canopies of similar dimensions.
Growth slows somewhat but remains steady at around 6–12 inches per year. Optimal fruit production also commences in the mature phase.
Proper pruning practices are employed during this time to maintain an open center and maximize sun exposure to developing olives.
Fertilizer is applied periodically to boost nutrition based on soil tests. Pest and disease management also becomes more important to protect the foliage and next year’s flower buds.
Olive trees can remain highly productive into old age if given proper care.
Olive Tree Fruiting Stages
Flowering Stage
The fruiting cycle begins in spring, when mature olive trees send out clusters of small, white flowers. For commercial orchards, flowering typically occurs from April through mid-June, depending on variety and climate conditions.
Warm days and cool nights are ideal. Pollinating insects, such as bees, are important at this time to transfer pollen between flowers in order to set fruit.
Weather that is too cold, windy or wet can reduce pollination success and subsequent olive yields.
Fruit Set Stage
Once pollinated, tiny olive ovaries inside the flowers begin developing into fruits known as drupes.
During this set period from late spring into summer, environmental and cultural factors influence how many flowers ultimately become olives.
Adequate soil moisture and nutrients encourage strong fruit set. Excessively hot or dry spells during flowering, on the other hand, can cause the shedding of small, immature olives.
Fruit Development Stage
As summer progresses, olive fruits, or drupes, develop fully on the trees. They will steadily grow in size, changing color from green to shades of red, purple or black, depending on variety.
This critical growth period lasts around 3 months. During this time, olive trees require consistent watering, as the bulk of fruit growth occurs in June through August.
Supplemental irrigation may be needed in hot, dry climates to prevent stress and ensure olives reach their optimal size before harvest.
Nutrients are also actively transported to the developing olives through proper fertilization. Avoiding stress on the tree optimizes yields of large, high quality olives.
Maturation and Harvest Stage
By late summer and early fall, olive drupes have fully matured, changing from their growth colors to a dark, shiny black or purple hue.
This signals they have reached peak oil content and flavor. The ideal timing of harvest depends on the intended use of olives—for oil, table olives or fruit snack purposes.
For oil production, growers monitor drupe color changes and check that internal oil concentrations have peaked, usually in October through December, depending on location.
Table olives are typically still firm and green when picked. Using taste, color and pressure tests helps determine optimal harvest windows.
Careful fruit collection methods are then employed by hand raking or shaking trees to collect mature olives.
Tips for Maximizing Olive Tree Growth and Yields
There are several cultural practices olive growers can employ throughout the trees’ lifecycles to promote healthy growth and high-quality production.
Proper Pruning
Light annual pruning of nursery trees aids structure development. Young trees require minimal cuts to establish shape.
Mature trees benefit from summer pruning to improve airflow, sun exposure and next season’s flowers. Only remove diseased or dead branches as needed.
Balanced Fertilization
Soil tests help determine supplemental needs. Generally, apply a complete, balanced fertilizer in spring and fall.
During flowering/fruit set, apply nitrogen to aid growth. Avoid nitrogen once olives are large to reduce vegetative growth over fruit production.
Adequate Watering
Young trees need regular watering, while established trees can typically rely on rainfall once roots are fully developed.
Monitor soil moisture and provide irrigation as needed during the hottest and driest periods, especially around flowering and fruit filling in the summer.
Pest and Disease Management
Follow an integrated program. Use preventative measures like pruning, weeding and the removal of diseased plant material.
Spot-treat any significant issues that arise with approved organic or chemical controls.
Grafting and Varietal Selection
Graft desirable scion varieties onto hardy, pest-resistant rootstocks. Choose varieties suited to the growing region’s climate and intended olive products.
Common Pests and Diseases
Olive growers must also monitor and manage any major issues that could impact trees and yields. Here are some of the most prevalent:
Olive Fly (Bactrocera oleae)
The olive fly larvae feed within olive drupes, causing fruit to ripen unevenly or drop. Integrated programs aim to prevent damage through sanitation, traps, and organic or chemical sprays timed with lifecycles.
| Stage | Management Strategy |
|---|---|
| Egg | Remove wild/dropped olives where flies lay eggs. |
| Larva | Monitor for maggots in fallen olives. Spray approved materials if >5% infestation is seen. |
| Pupae | Apply fungicides or residual sprays to surviving larvae in the soil over winter. |
Olive knot Disease (Pseudomonas savastanoi pv. savastanoi)
Caused by bacteria, symptoms include growths or knots on stems and leaves, which can girdle and kill branches over time. Prune out all knots during dormancy. Apply copper sprays preventatively in wet seasons.
Verticillium Wilt (Verticillium dahliae)
A soil-borne fungus that enters through roots and blocks water/nutrient transport. Symptoms include wilting, stunting and eventually tree death. Remove and destroy infected plants. Grafting resistant rootstocks helps control their spread.
The integrated approaches above provide examples of proactive management strategies to keep olive trees productive for many fruiting seasons to come.
Conclusion
Understanding the typical growth cycle and fruiting stages of olive trees supports long-term, sustainable orchard management practices.
By implementing recommended cultural techniques tailored for each phase, such as fertilization, pruning, irrigation and pest control, growers can optimize canopy development, annual yields and harvest windows.
Proper planning helps ensure trees flourish from their first years in the nursery through a productive, mature lifespan, providing olives for various products.
With dedicated care and by reading the signs their trees provide each season, olive growers can gain a deeper appreciation for these stalwart Mediterranean crops.
The knowledge gained from understanding olive tree growth and fruit production is invaluable for cultivating healthy, high-yielding orchards for years to come.