Bonsai In September This is the start of autumn and you will start to notice your deciduous trees slowing down their growth rates and the leaves will be under going chemical changes which will end on colour changes. The weather will be cooler and with wet periods potentially. Here is a quick generic guide to bonsai in September but for individual species you may need to adjust the guidance as well as for the developmental stage your bonsai trees are at.
Watering Continue to check your trees daily and water as required and you will have noticed they will be slowing down their water uptake and not drying out as quickly. Therefore start to review your watering regime in line with the trees uptake and weather conditions. Water in the mornings ideally and if necessary water more than once a day.
Re-potting None required unless emergency repotting required where the pot is damaged or there is a pest concern or drainage issue. Try not to damage the roots during an emergency repot and just place the tree in another pot of the same size or larger for the time being until the correct repotting season without root pruning or disturbance.
Feeding This is the time to still continue feeding while the trees are active while they start to go into autumn. Organic feeds are preferable to chemical feeds including products like liquid seaweed and this can be fed daily as part of the watering regime or less often depending on the stage of development of the tree. Ideal feeding at this time is liquid feed as the watering regime has picked up and you can feed with each watering, and the general rule is little and often.
Pruning Continue to prune back any extension growths on deciduous trees.
Trimming Continue to trim long extension shoots to maintain the shape through regular trimming and remove the terminal shoot in some species to aid with creating a more compact form. Continue to prune tropical trees to maintain their shape and trim the new shoots.
Root pruning This is not applicable at present unless any trees are being repotted but for the majority of species they should already have been done.
Insects and pests Check for the repeat infestations of bugs and pests like green and black fly, red spider mite, scale insect, mealy bug as well as vine weevil beetles. With the change in weather insect pests can start to look for places to hide under the bark and in the soil. Watch out for the on set of mildew and prune out any damaged leaves or treat any infestations if found. Spray with insecticide as required or once a month for pest prevention using products like SB Invigorator. Pest control is rarely necessary in September but still keep an eye out for any latent pests.
Moss and weed control Continue to keep this in check and treat or remove unwanted moss and remove any newly forming weeds.
Wiring This is a good time to start reviewing the wire on trees if present as this should become easier to see as the tree starts to go into autumn.
Protection None should be required currently beyond checking the trees are not becoming water logged if there is a period of wet weather. Assessment Continue to update your bonsai records and photograph your trees to record their progress.
Tools This is something everyone should do each time they use their tools but often it is not easy to do depending on how often you are using your tools. However, it is good practice to clean and sharpen your tools after use and this is a good time to go through your tool kits and clean them up before the start of the pruning season.
Display areas This is a good time to check your display areas to ensure your trees are being shown to the best advantage to get the full autumnal display possible.
Propagation This is a good time to check any air layers for signs of drying out and to see if they are well rooted and if they are they can be separated from the parent plant and potted up. If they have not developed sufficient root then leave in situ to review next spring but ensure to continue to keep moist each month.