Olea europaea – Olive Tree seeds

Description

Olives (Olea europaea) are long-lived, evergreen trees native to the Mediterranean, cultivated for thousands of years for their fruit and oil. They’re drought-tolerant, highly ornamental, and a practical addition to the garden for anyone interested in food self-sufficiency. Fruiting varieties produce small, firm drupes that can be pickled or pressed for oil.

Trees typically reach 4–8 metres tall with age, though they can be kept smaller with pruning. Olives thrive in full sun and free-draining soils, including poor or rocky ground. Once established, they are very drought-hardy, but good fruiting benefits from occasional deep watering and adequate nutrition. In New Zealand, they grow best in areas with hot, dry summers and cool but not extreme winters.

Most olive varieties need around 200–500 hours of winter chill (under 7°C) for consistent fruiting. They are tolerant of light frosts down to –10°C once mature. Although some types are self-fertile, better yields are achieved with cross-pollination. To ensure good pollination when growing from seed, raise at least five to eight seedlings, as seed-grown olives are genetically variable and may not all be compatible.

Germination and Cold Stratification:
Olive seeds are slow to germinate and often require patience. Stratify seeds in moist sand or peat for 8–10 weeks at 5–10°C, then move to warmth (20–25°C). Scarifying the seed coat before stratification can improve success. Even under ideal conditions, germination may take several months and be sporadic.

Outdoor Stratification Tip:
In cooler parts of New Zealand, olive seeds can be stratified outdoors over winter. Sow into pots or trays filled with moist, well-draining mix and place them somewhere protected from rodents. Natural winter temperatures will gradually work on the seed coat, allowing germination to occur in spring or early summer.