AusBonsai

I've been working through the collection trying to get to all the trees that need repotting this winter.

I did the wisterias first. Found out the hard way that they really need doing every year. If I don't repot each year the pot is so full of roots that water cannot penetrate and the tree really suffers in summer.

The smaller bonsai were next. They also need doing each year because the smaller pots get filled with roots by autumn and the trees really suffer the following summer if they don't get root pruned before the growing season.

After that I tackled the larger trident maples.
Here are some photos to give you an idea of how I go about root pruning. You can see how crowded the root ball is, especially right at the bottom. It is quite difficult to comb out the tangled roots. I figure if I'm only going to cut them off anyway why spend time combing so now I just cut a few cm off around the edge of the root ball, right through the mix and roots and all. Then use the root shears again to slice several cm off the base. After that it is much easier to comb out the remaining roots to see where they come from and where thicker ones are. Finally shorten the finer roots with the root shears and cut any thick ones right back short with shears, branch cutters or root cutters.
This is how much I took of this one this time. Note that most of the remainder is solid wood - base of the trunk, main roots that have fused together, etc. Only about 2cm around the edges is actually finer feeder roots. The photos from the front don't really show the ramification very well. Here's a shot from above to show the branching.

Fantastic work. I also repotted several of mine yesterday. Have a couple more to go. For some reason developed a blister on my finger and it hurts like a bitch.

My hands are pretty tough but after a day of hacking through tough roots last weekend the root shears left me with a blister as well so I know your pain

eek, I've got some wisteria in large pots from a nursery closing down sale...so I should root prune them now? The pot looks very full and solid with roots.

I think I've done all my tridents, hope they all manage, cos I've taken a leaf out of your book on cutting back severely!

I am in Brisbane like Mel, and have only repotted one of my Wisteria so far, because the buds aren't swelling on the others yet. Should I do them now anyway?

Going on my experiences I would repot wisterias now rather than try to get them through a summer.
I have read recommendations to repot after flowering but mine are always in leaf by then and I've been reluctant to cut roots at that stage. Now that I have done some trials with repotting tridents in leaf I think differently and it is probably OK to repot wisteria in leaf after they flower? Hopefully someone with experience can provide comment here.

If you miss this opportunity there are other alternatives.
After it started wilting each day I kept mine going by keeping it in a tray of water all summer. Each morning the (3cm deep) tray fills up with water so the densely packed root ball can absorb enough water to get through the day. I've seen growers recommending to keep wisterias in water over summer to aid flowering. Maybe the reason is to keep them alive?

Your trees, your choice

Thanks Neil, I had planned on letting it flower and repot in Summer, and yes, it's (even now) sitting in a tray because it's in a very warm spot during the day.

I might just take a peek at the roots tomorrow and make a decision then.

Cheers

Hello all, just a note on Wisteria while you're at it, they like being somewhat rootbound in their pot, they flower better. If you plan on displaying them in flower, don't repot them in the same Spring. They love water and uptake a lot of it in warmer weather, they will let you know when they need more water, they get the droops but you shouldn't wait till then. It's just part of understanding the requirements of different plant species as Bonsai. Prune after flowering, they also love food, make it a low "N" fertiliser, they will give a few growth flushes through Summer if given the right treatment. And don't forget "SUN" lot's of sunshine.

Thanks for your contribution Internode. I have heard all those things mentioned in relation to wisteria before but sometimes I like to question 'traditional' knowledge. I've found plenty of examples where alternatives seem to be better.

they like being somewhat rootbound in their pot, they flower better

How do you know they actually like this? Most plants will flower well under stress. They are making a last ditch attempt to pass on genes in case they die. Maybe there is a way to have healthy wisteria that flower well but are not at risk.

If you plan on displaying them in flower, don't repot them in the same Spring

Do you have a reason for this? I assume it relates to a top heavy plant covered with flowers that does not have enough roots established to physically support it in the pot? What about repotting after flowering? Autumn repotting?

I agree they seem to need plenty of water. That's one of the problems I've had with not repotting - just can't get enough water into the pot when it is full of roots. They do indicate when they are thirsty but very soon after drooping all the leaves drop off though mine have always grown back a few weeks after being rehydrated. It seems to be a very fine line between 'well watered' and 'at risk'.
I also like to give all my trees lots of sunshine but, again, lots of sunshine aggravates the water problem. Balancing sun, water and root seems to be the tricky part. Thoughts?

I have only 1 wisteria in a bonsai bot and usually repot it in spring after flowering and like Shibui, they have leaves by then but it does not seem to bother it.
I think it does not get enough direct sun in winter to flower as profusely as it may otherwise do so:-(.
It will be repotted this week before bud swell and see how it goes this year.

It is potted in a much deeper pot than would otherwise be the norm to keep more water available for it rather than on a tray.

Quite a few others in grow pots and I repotted all them a month or so ago.

Ken