|Olive, Fruitless||(Olea europaea)||U,W ^|
| watch out for scale insect infestation; let soil become nearly dry before watering again; better to wire green wood; roots grow quickly; can reduce rootball down best in June or July; transplants best in summer; even cut-back large old landscape specimens are said to transplant successfully; only produces flowers on ends of second-year growth, so a properly trimmed bonsai should never flower; keep suckers growing from trunk base under control; take soft cuttings for rooting in October, March or April. [Oleaceae; Lamiales]
General Information: The olive has deep green leaves with greyish undersides, and produces yellowish-white flowers followed by green or black fruit in late summer or early fall.
The olive is a tough customer – it is tolerant of wind (both hot and cold), soil condition and elevation (O. europea can live at altitudes up to 4900 ft.!) and can live 800 to 1000 years.It is much loved by bonsai enthusiasts as much for its rich historical and mythical lore as it is for its elegant shiny green leaves and trunk which takes on an aged, stony appearance when old.
Lighting: Full sun in summer, less in winter. Requires 1000 Lux as an indoor plant.
Temperature: Leaves can withstand temperatures down to 43F; the roots dislike freezing temperatures, although survival at temperatures down to 25F has been reported. Considered to be hardy in zone 9. The olive can be successfully grown as an indoor plant, but it is best to keep it outdoors in the summer, and should be kept below 64F in winter. To encourage fruiting, the plant should be kept for several weeks with nightly temperatures of 35F and daily temperatures of 60F.
Watering: Water thoroughly, but keep slightly dry. Reduce watering in winter. The olive may benefit from daily misting.
Feeding: Every two weeks from spring to autumn. Do not fertilize for three months after repotting. Use liquid bonsai fertilizer or half-strength general purpose plant food. It can benefit from an addition of pulverized organic fertilizer in mid-spring.
Pruning and wiring: Suitable for all sizes, and all styles except broom. Creating your own jin/shari is not a good idea as the bark cracks easily, leaving the tree exposed to fungal infestation, although in my experience there is some natural die-back which may be used in the design of the tree. Marco (Italy) talks extensively about styling the olive:
Propagation: Propagation by seed has only a 30% success rate. Cuttings are more successul, and quite large diameter cuttings (up to 2.5 inches) may be rooted. It is easiest to root cuttings first in a glass of water. The olive also suckers, and may be propagated by division.
Repotting: Every 2-3 years in spring, as buds sprout. Trim about 1/3 of the root ball, and remove a proportional number of the old leaves. If more drastic root pruning is needed, complete defoliation is advised. Repot in free-draining, slightly calciferous soil.
Pests and diseases: Aphids, ants, black mold, scale
Some species suitable for bonsai: