How to Grow Olive Tree Colossal

Olive Tree Colossal

Olea europaea 'Colossal'

tree

Colossal is a large-fruited olive cultivar prized for its exceptional fruit size and productivity. It produces abundant olives suitable for both table consumption and oil production, and is a vigorous, attractive ornamental tree. This variety thrives in Mediterranean climates and develops an attractive silvery-green foliage canopy.

Growing Conditions

☀️

Sun: Full sun, 8+ hours daily (preferably 10+ hours for optimal fruiting)

💧

Water: Low water needs once established. Water deeply but infrequently during growing season. Reduce watering in winter. Drought tolerant but produces better with consistent moisture during fruit development.

📏

Spacing: 240 inches

📅

Days to maturity: Trees typically produce significant fruit by year 3-5, full production by year 7-10

🌱

Planting depth: Plant at same depth as root ball; keep trunk base above soil line to prevent rot

Soil

Type: Well-draining sandy, loamy, or gravelly soil

pH: 6.0-8.5

Amendments:

Perlite or coarse sand for drainage improvement Compost for organic matter Limestone if pH is below 6.5

Growing Zones

Find your zone →

Thrives in zones 8b-11, best in zones 9-10. Can be grown in zone 8 with winter protection.

8b 9a 9b 10a 10b 11a 11b

Growth Stages

Establishment

1-2 years

Young tree focuses on root development and branch structure. Limited flowering in first 2-3 years.

Water regularly but allow soil to dry between waterings. Establish strong scaffold branches through light pruning. Protect from harsh winds in first year.

Vegetative Growth

2-5 years

Tree develops strong branch framework and silvery-green foliage. Canopy becomes fuller and more mature.

Prune to maintain open canopy structure. Remove crossing or inward-growing branches. Apply light nitrogen fertilizer in spring.

Flowering

3-4 weeks in spring

Small white or cream-colored flowers appear in spring on previous year's wood. Flowers are inconspicuous but fragrant.

Avoid heavy nitrogen fertilization which reduces flowering. Ensure adequate winter chilling (200-300 hours below 45°F for better set). Provide good air circulation.

Fruit Development

3-4 months

Olives develop from fertilized flowers, enlarging significantly over summer. Colossal produces notably large fruit (1-1.5 inches or larger).

Thin fruit if over-set to achieve larger individual olives (thin to 6 inches apart). Provide consistent water during this stage. Apply potassium-rich fertilizer if needed.

Harvest

6-8 weeks

Olives change color from green to purple-black when ripe (fall to early winter). Fruit is ready for harvest based on intended use.

Harvest green olives in September-October for table olives or oil with peppery notes. Harvest fully black olives in November-December for milder oil. Handle fruit gently to avoid bruising.

Companion Planting

Plan your garden →

Plant with:

Rosemary Lavender Thyme Garlic Onions Citrus trees Pomegranate

Avoid planting near:

Black walnut (produces juglone) Shallow-rooted plants competing for water Plants requiring frequent water

Common Pests

Use pheromone traps for monitoring. Harvest fruit promptly when ripe. Apply spinosad or neem oil if populations warrant treatment. Maintain good sanitation.
Prune out heavily infested branches. Spray dormant oil in winter. Apply horticultural oil in spring and summer for active infestations.
Prune out and destroy infected branches. Sterilize pruning tools between cuts. Apply copper bactericide to pruning wounds in wet seasons.
Remove fallen leaves and infected twigs. Improve air circulation through pruning. Spray copper fungicide in fall and spring if disease pressure is high.

Uses

🍳

Table Olives & Curing

Culinary

Colossal olives are exceptionally large and meaty, making them ideal for curing as table olives. The large fruit size and excellent flavor make them superior for brining, lye-curing, or fermentation. [source]

🍳

Extra Virgin Olive Oil

Culinary

Colossal olives produce flavorful, robust olive oil with herbaceous and peppery notes when harvested at proper ripeness. The oil is suitable for cooking, drizzling, and culinary applications. [source]

🏠

Ornamental Landscape Tree

Household

Beyond fruit production, Colossal olives serve as beautiful, long-lived landscape specimens with silvery-green foliage, attractive gnarled trunks, and low maintenance requirements in Mediterranean climates. [source]

💊

Polyphenol-Rich Extract

Medicinal

Olive leaves and fruit contain high concentrations of polyphenols with antioxidant and anti-inflammatory properties. Traditionally used in herbal preparations for cardiovascular and immune support. [source]

🎨

Wood & Timber

Craft

Ancient olive trees develop beautiful, dense, grain-marked wood valued for woodturning, carved objects, and decorative items. Olive wood is prized for olive wood serving boards and kitchen accessories. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

For table olives: Harvest when green or turning color (September-October), cure in brine or lye solution. For oil: Harvest fully ripe black olives (November-December) for best oil quality. Use a catching cloth under branches to minimize fruit damage. Store harvested olives in cool conditions and process within a few days for best quality.

Fun Facts

🌱 Olive trees are among the longest-lived fruit trees, with some cultivars living 500+ years and continuing to produce fruit well into old age.
🌱 The Colossal variety can produce very large fruit—some olives exceeding 1.5 inches in diameter—making them the largest among commercial olive cultivars.
🌱 Olive trees don't require cross-pollination and are largely self-fertile, though cross-pollination with compatible varieties can increase yields significantly.

Want personalized planting timelines?

Get started free