Seasonal Notes from Shibui Bonsai

Watering is once again top of the list as the days get warmer and longer. I have found that rain often does not provide enough water to keep my bonsai watered. I guess the leaf canopy of my bonsai shelters the pot so most of the rain probably does not even make it to the roots. That means I still water, even after it has rained.

Feeding should have started by now. I’m feeding my trees every 2-3 weeks to get optimum growth. I like to use different fertilisers to make sure my trees are getting a full range of nutrients. I use Thrive, powerfeed, chook poo pellets and worm juice at different times during the growing season. There’s no need for half strength fertiliser on bonsai. Apply it at the recommended rates for best results.

One species I am not fertilising at the moment is advanced pines. These are the ones I intend to decandle next month. Reducing fert for a few weeks before removing the candles should give me smaller new candles and shorter needles when they sprout again. I’ll start feeding them again after the new shoots have developed and started to harden off.

In the last few weeks I’ve root pruned and potted most of the azaleas. I’ve also trimmed them up top to get plenty of new shoots. Cut all long growth short so you’ll get lots of new shoots that will flower next spring.

I’ve also started repotting my natives. They seem to do far better when roots are pruned in warmer weather. More at our meeting next week where the topic for the evening is native plants as bonsai.

Trimming continues. Maples just keep growing so they also need pinching back every few weeks. On many trees I let the shoots grow to around 15 cm long which is about 3-4 pairs of leaves before trimming the shoot back to just a single pair of leaves. Chinese elms have an alternating leaf pattern but are treated in a similar fashion – shoots grow to around 10-15 cm then cut back to only 1 or 2 leaves near the base of each shoot.

Trees that are still developing (where you want the trunk to thicken or branches to grow and ramify) can be allowed to grow even longer before cutting the new shoots. For much older trees where I don’t want the branches to get thicker I usually try to pinch the shoots when they are even smaller, often as soon as they grow a couple of sets of leaves they get pinched back to the first ones on the shoot. On those trees I also hunt for any stray new shoots that have sprouted from the trunk and branches. Leaving many shoots to grow from the trunk can cause it to thicken in that area which gives ugly thick areas on the trunk which can really show up when the tree is bare in winter.

Late winter and early spring cuttings are starting to develop roots so I’ve been potting up the ones with roots so they can grow bigger. Last week I potted up Chilean myrtle, zelkova and pomegranate cuttings.

I cut back some of the developing pines. They’ve been allowed to grow without trimming for 2 years so the lowest needles are getting ready to drop later in summer so now is the time to cut right back to the older needles and they should sprout new buds from those needles.

Looking forward to bonsai tasks for the rest of November and December:

Continue watering and fertilising. I’m currently watering most bonsai once each day. As it gets hotter I’ll step that up to watering each morning and evening to make sure they are getting properly hydrated.

Mid December is when I decandle the more advanced pines here at Shibui Bonsai. Every candle is cut right near the base to force the trees to grow new shoots. Those trees are also put on a diet for a few weeks before and after decandling which will help to restrict the size of the new shoots and needles.

As the azaleas sprout new shoots after the initial post flowering prune I’ll cut the new shoots as they grow longer. Like other species, the more you cut the denser the foliage will become and on azaleas lots of shoots means lots of flowers next spring. Embryonic flower buds are forming in autumn so if I want plenty of flowers I’ll stop trimming them in February and start feeding with a flower type fertiliser to promote lots of stronger flowers.