Olives

Olive trees (Olea europaea) are iconic evergreen trees that bring a touch of the Mediterranean to any garden.

With their silvery-green, leathery leaves and often gnarled trunks, they exude a sense of timeless beauty and resilience.

Appearance and Characteristics

• They are slow-growing trees that can eventually reach heights of 15-30 feet, although dwarf varieties exist that stay smaller, around 6-8 feet.
• Their foliage is distinctive, with feather-shaped leaves that are grey-green on the upper surface and a lighter, silvery-white underneath. This gives the tree its characteristic shimmering appearance in the breeze.   
• In spring, they produce small, creamy-white and yellow flowers, which, if pollinated, will develop into the familiar olive fruits.   
• Olive trees are known for their longevity, with many living for hundreds of years, and some even exceeding a thousand years. Their root systems are incredibly robust, allowing them to regenerate even if the above-ground parts are damaged.   

Growing Conditions

• Sunlight: Olive trees thrive in full sun, needing at least 6 hours of direct sunlight per day. A south or west-facing position is ideal.   
• Soil: They prefer well-drained soil and are quite tolerant of poor, rocky, or gravelly soils. Good drainage is crucial, as they will not survive in waterlogged conditions. If planting in clay soil, improving drainage is essential.   
• Watering: While established olive trees are drought-tolerant, young trees need regular watering, especially during dry periods, to help their root systems establish. For container-grown trees, allow the top few inches of soil to dry out between waterings. Water sparingly in winter.   
• Temperature: Olive trees prefer mild climates with hot, dry summers and cool winters (ideally between 40°F and 50°F for a two-month dormancy period to encourage fruiting). Mature trees can tolerate short periods of temperatures as low as -7°C (20°F), but young trees and new shoots are more susceptible to frost damage. In colder regions, container-grown trees can be overwintered in a frost-free location like an unheated conservatory or greenhouse.   
• Wind: Choose a sheltered position, protected from strong north and east winds.

Growing in Containers:

• Olive trees do very well in containers. Choose a large pot with good drainage and use a loam-based compost mixed with about 20% horticultural grit to improve drainage.   
• Place the container in a sunny spot and keep the soil moist during the growing season, reducing watering in winter.   
• Feed container-grown trees with a balanced liquid fertilizer monthly from early spring to mid-August, or use a slow-release fertiliser twice a year.
• Repot when necessary into a pot about 50% wider and deeper than the previous one.  

Fruiting

• Olive trees typically start producing fruit between 3 to 5 years old.
• Most olive varieties are self-fertile, but planting another variety nearby can increase fruit yield through cross-pollination, which is wind-dependent.   
• A two-month cold spell in winter and fluctuating day/night temperatures are needed to initiate flowering and fruiting.   
• Olives are usually harvested in autumn, turning from green to black as they ripen. They are not palatable straight from the tree and require curing in brine, oil, or water.   

Pruning

• Pruning helps maintain shape, remove dead or diseased wood, and encourage good leaf growth. 
• The best time to prune is typically in late spring or early summer, after the risk of frost has passed. Avoid pruning after August to allow the tree to heal before winter.  
• Pinching out the tips of young shoots encourages bushier growth.
• For fruiting, some thinning of the canopy to allow sunlight penetration is beneficial as olives fruit on the previous year’s growth.  

Varieties

There are numerous olive tree varieties (cultivars), each with its own characteristics in terms of fruit size, oil content, flavour, and growth habit. Some popular varieties include:

• Arbequina: Small tree, good for containers, relatively cold-tolerant, produces small, fruity olives. 
• Leccino: Popular Italian variety, easy to grow, tolerates a wide range of temperatures, good for both oil and table olives. Self-sterile, needs a pollinator.  
• Frantoio: Another popular Italian variety, known for producing high-quality, fruity oil. Often self-fertile and a good pollinator.  
• Picual: Hardy and vigorous Spanish variety, high yielding, typically used for oil. Self-fertile.  
• Mission: American variety developed in California, more cold-tolerant, dual-purpose olives.  
• Pendolino: Small, weeping form, often used as a pollinator. Self-sterile.

Olive trees are more than just fruit producers; they are beautiful, resilient trees that add a touch of Mediterranean charm to any garden and can even thrive in containers, making them suitable for a wider range of climates.