Olea europaea (olive)
Olea europaea is a good species for beginners. Wild olives, Olea europaea sylvestris, are particularly suited to bonsai due to their smaller leaves.
There are a variety of guides on the internet with contradictory informations on how to grow the olive as bonsai, probably due to the differences in climate from its Mediterranean native region. A good rule of thumbs is to dismiss guides advising to bring the trees inside heated houses during winter.
This species has a peculiar fine root system that grows slowly and don't need frequent repotting, as a consequence the substrate must be very stable to avoid compacting with time. It must also be very draining because the trees don't like the combination of cold and wet soil. Therefor a mix of pumice and pozzolan is well suited. There is less consensus for the best time for repotting, some advise to do it just before spring begin and some prefer the end of spring or early summer when the trees are already growing. The latter opinion seem correlated to locations in colder climates.
Links
- https://www.bonsaiempire.com/tree-species/olive
- strong pruning in late winter
- cut back long shoots to one or two pairs of leaves
- healthy specimen can be defoliated
- young branches can be wired
- repot in spring before the buds begin to swell, every two or three years and remove about a third of the roots
- use a well draining soil mix
- https://www.mistralbonsai.com/en/olive-bonsai-care-guide-the-secret-to-take-care-of-your-olea-bonsai-step-by-step (based in Spain)
- can be wired throughout the year
- pruning in early March (before spring begins)
- pinching can be done between April and October
- can be re-potted every 3 or 4 years
- use 70% Akadama and 30% Pomice
- fertilise them from March to October
- https://www.kaizenbonsai.com/bonsai-tree-care-information/heart-of-the-mediterranean-the-olive-tree-as-bonsai (based in the UK)
- old is not our worst enemy
- the big problem is the combination of cold and wet
- trees that are overwintered in the dry will grow much more strongly in summer
- if you do have to re-pot an olive the ONLY time to do this is mid-summer
- olives re-potted in spring tend to produce poor subsequent growth in that year and then return to normal in the following year
- choose a hot period between mid June and mid July
- don't prune growth prior to re-potting the tree needs all the leaf mass it can get
- growing media should be alkaline, olives naturally grow on limestone
- 80% graded Pumice - 10% Moler clay - 10% clean chipped pine bark
- use any high quality organic fertiliser so long as it incorporates multiple nutrient sources
- when pruning an olive to build ramification it is important to cut all new shoots at the same time