Acacia spectabilis, Mudgee wattle, grafted tree in a pot

[Joshua]

Hello,

I bought this Acacia Spectabilis (Mudgee Wattle) for my parter. The aim is to have it big and bushy and hopefully get plenty of flowers.

In this case, we're not especially after a beautiful bonsai with a thick trunk, good taper, nebari, or a shallow pot. So technically it's not really for bonsai, but still a tree in a pot

I have some questions but also open to general care advice if anyone is happy to share.

Currently it's in it's original pot, about 14cm wide. It's grafted. Standing about 1m tall and tied to a stake in the pot to help keep it up.
We're thinking to grow it up against one end of our balcony, using that trellis to help and to keep it a wide rather than a big round shape. Maybe final height 1.5m (from soil surface).
We're not after fast-as-possible growth, but just keeping it healthy for a good number of years and hopefully finding a way to keep the maintenance fairly simple.
As for pruning/training, I was thinking of leaving it alone until it gets to a bit over the final height we're after, then cutting back to encourage some branches and 'width'.

Since I think we'll only ever be potting up and not aiming for a shallow pot, we'll be keeping it in just standard potting soil rather than a bonsai substrate. Currently it's in something that seems quite heavy and gravelly - in the nursery they said it was a Mediterranean potting mix.

- Should I wait until it gets a little closer to pot-bound or does it look it will need more space this year?
(to me it seems already quite tall for that pot size and it seems to be growing fast).
- Should I generally just slip-pot it up, or would there be a benefit to trimming the roots to some extent every time?
- Are they sensitive to 'over-potting'? Should I look at just potting up little by little every couple of years? Or go straight for a fairly big pot? If so, how big?
- Could it handle living in a self-watering pot/bucket or a wicking bed type system?

Photos are about a month old and the flowers are all gone now.

wattle 2022-03-06 full.jpeg

wattle 2022-03-06 top.jpeg

wattle 2022-03-06 roots 1.jpeg

wattle 2022-03-06 roots 2.jpeg

wattle 2022-04-09 suckers.jpeg

[shibui]

I'm surprised to see an A. spectabilis grafted. Does the label give any indication why? special clone? hardiness? growth rate?

re potting up: The root system looks just right to go into a bigger pot. Better to do that as the roots are just filling the previous pot than after they get really pot bound and acacias do grow quick so probably better to go earlier than later.
No need to root prune each time. If it is pot bound some cutting or teasing of roots is important but those roots will easily move into the new soil as they have not started circling badly yet.

At this stage you can probably go up a couple of pot sizes at a time without compromising root health. That should be safe to go into a 25 or even 30 cm pot this time.

Self watering pots will be fine for acacia. Even a good wicking system should be OK provided the soil does not stay soggy.

[Joshua]

I'm surprised to see an A. spectabilis grafted. Does the label give any indication why? special clone? hardiness? growth rate?

We didn't keep the label but I can ask about it next time I pass by the nursery.

[Joshua]

This tree hasn't been doing so well.

I think the potting soil that the nursery recommended was really not ideal.
It was very dense and very fine. It seemed to both drain badly and retain a lot of water.
Actually on the packet it seems the intention is that it should be used as soil for when planting in the ground. It also says something like "can also be used for repotting by mixing it 30% with existing potting soil"

On top of that it can get windy on the balcony which is not ideal apparently for these, and perhaps not ideal sun exposure.
It seemed to start doing a little better when we brought it inside for part of the winter.
We got some flowers from it too. But it had already lost much of it's volume by that point.

I feel like it needs an emergency repot but it's probably still a bit too cold.
I'm thinking to cut the roots back quite a bit in order to replace most of the soil for something better, and put it in a smaller container (for now).
It's not quite time because we're expecting a few more cold spells but I also want to get this done asap as soon as it's consistently a bit warmer.

Despite all this it doesn't look like it's about to die either and actually I get the feeling it's about to start pushing out some new growth which I suppose is a good sign.

(ps. I never did end up asking the nursery about the graft..)

wattle 2023-03-12 2.jpeg

wattle 2023-03-12 1.jpeg

[Joshua]

This has been sulking for just about a whole year. Although it did give us some flowers this past winter. Starting to get a bit more consistently warmer and it's now finally pushing out some leaf buds.

Looking to trunk-chop because it's tall and skinny and I want it somewhat more compact. Currently it gets pretty beaten up by the wind, falls over easily, etc. (pot shape doesn't help either).

Not sure if it's better to chop before the new buds turn into branches or let them get some vigour and regain some more energy. Thinking mostly that chopping now would give the new future branches a fuller season.

And somewhat reassured reading the acacia species guide https://www.ausbonsai.com.au/forum/view ... ?f=49&t=11 :
- "Wattle must be pruned back hard in early spring (after flowering) as they are prolific growers and will quickly loose their shape."
- "Cut back to bare wood at repotting time if required."
- "They back-shoot well and handle cutting back to bare wood so total reshaping is possible.".

[dansai]

I would be inclined to let that first growth spurt go. It sounds like it needs an energy boost. if you cut now it will have diminished energy to put into new growth as its already putting that into the growth you are seeing. Let it push, harden off for a while and then cut back. That way it has regained the sugars it has used and will be building up new stores. It will more likely give a better and stronger response which is what you want to build up the trees health

[MikeK]

...
- "Cut back to bare wood at repotting time if required."
- "They back-shoot well and handle cutting back to bare wood so total reshaping is possible.".

Not sure about this ... for most Acacia my understanding is they do not backbud on bare wood.

[GavinG]

I have found no Acacias that you can cut back to bare wood. You might like to put it into a larger pot, in the growing-on phase, and get some serious momentum happening. Maybe cut back to the lowest strong branch, and see what it does. When it comes time, be somewhat gentle with the root pruning. Good luck!

Gavin

[treeman]

A spectabils is a beautiful species (but probably short lived) I would buy some seeds, sow them and not waste another moment with this tree.
All acacias MUST have rhizobium bacteria added to the soil to do well.