Acer Palmatum - what size container

Hello,

I've just bought a small (20-30cm) acer palmatum atropurpureum which I'll be planting in a container.

It's in a 9cm pot at the moment, and I'd like it to end up in a square wooden planter I have, about 1 ft deep by 1.5 ft across. Is that likely to be suitable for it, and can I plant it in there straight away or ought I to pot up in increments?

Thanks for any advice!

I have Acer Palmatum Dissectum Garnet growing in a large stone pot and ericaceous soil. I bought it last year in a 1lt pot and its already doubled in size. I do recall that their roots travel quite deep, here is a good link

http://www.gardenersworld.com/plants/acer-palmatum-atropurpureum/2545.html

Wintersong wrote (see)

... ericaceous soil....

Well that's what I thought, namely that ericaceous soil or compost is essential.

However, the link quoted (http://www.gardenersworld.com/plants/acer-palmatum-atropurpureum/2545.html) actually says that Acers can grow in Chalky/Alkaline soil.

Is that correct?

I have an acer in a pot. Acers have lot of foilage so they use plenty of water. If an acer is in a pot, then it will need watering regularly. Because tap water is alkaline, I've always believed that tap water should not be used. I have a rain water tub, and keep that precisely for plants that don't like tap water. Maybe I'm going to a lot of trouble unnecessarily.

I think it's generally a good idea to pot up one stage at a time, partly to keep the plant firmly contained and supported. You could always use your big planter as an outer pot and put the plant in a smaller pot inside it for the meantime (this also makes it easier to move around if required).

We have two acers of this sort (the dark purplish ones) in pots on the patio. The inner pots are about 25 cm across. They've been there for 4 or 5 years and at first I put some pansies around the edge to fill up the pot and add some winter colour. Now the roots of the acers have filled up the pots, so I've stopped trying to squeeze pansies in. The plants are now about 1 to 1.5 metres in height and width. They look splendid despite being a bit potbound and in a hot, sunny spot.

I use rainwater when it's available but I'm sure I've used tap water at times. Ours is soft water so it may not make much difference. I don't think we used ericaceous compost, just ordinary multi-purpose. I do give them some sort of feed from time to time during the summer.

What is particularly pleasing to me is that the trees were a free (p&p only) offer from the Radio Times.

I don't know that acers will tolerate very alkaline soil, although they are fine in neutral soil. Having said that, I do water mine with tapwater when necessarily, and it is fairly hard.

Container size - the size quoted is probably too small for a final size, but it'll take a while to get there.

springfieldbean wrote (see)

Hello,

I've just bought a small (20-30cm) acer palmatum atropurpureum which I'll be planting in a container.

It's in a 9cm pot at the moment, and I'd like it to end up in a square wooden planter I have, about 1 ft deep by 1.5 ft across. Is that likely to be suitable for it, and can I plant it in there straight away or ought I to pot up in increments?

Thanks for any advice!

I agree with the advice given in Green Magpie's first paragraph, it makes a lot of sense. 

For long term residents, I do perfer to pot up in stages - yes, do pot on to encourage root growth and plant pot and all into your larger planter, just don't forget it's there.

BTW - I've never used ericaceous compost with any of my collection of maples that I'm beginning to mass, but I do generally use rain-water.

My acers do very well in pots with a mix of ericaceous and multi purpose soil. I know the advice is to use rainwater and I do make an effort with young plants but the established ones only get tap water and it all seems to work !. We live in a hard water area. I do find though that most damage is caused by cold winds.

On the subject of Ph for Acers, I have a green leaved one growing in the ground that has never suffered although the last ph test I did was neutral, (must do one again) I did read that the dark leaved type require acid or neutral at the least, thus mine is in a pot to be sure. Also, because I don't want to dig this beauty up if I ever love.

I use rainwater unless supplies are low at which point I might use either left overs spring water or tap water which is hard in my area. I'm sure a few doses won't harm it in the long run

Green Magpie wrote (see)

We have two acers of this sort (the dark purplish ones) in pots on the patio. The inner pots are about 25 cm across. They've been there for 4 or 5 years and at first I put some pansies around the edge to fill up the pot and add some winter colour.

Blimey! I bought my Acer last year as a tiny twig that needed supporting with canes to stop the wind snapping its stems. I did exactly as you suggest, sinking my potted on Acer inside its intended larger stone pot and hiding the rim with gravel but when I had to take it out of the outer pot at the end of the summer its roots had gone besserk, leaving its 2lt pot and travelling down into the soil through the drainage hole!  I was gob smacked, potted it directly into the stone pot and left it be. Earlier this year, I move the stone pot and its roots were still contained, thankfully.

I do wonder whether I should re-pot them, perhaps into the larger outer pots, but it gets to a point when the pot is too heavy to move, and you have to buy some special trollies or castors or something if you want to move the tub. I've decided that maybe they're happy enough being pot-bound, and I'll going to leave them until they show signs of distress.Some plants don't seem to mind. and I don't want them to get any bigger, so if they stick at this size and stay healthy, that's fine by me.

We do have another acer of the same variety and age that's planted directly into the soil. Admittedly it's beside a lonicera hedge, and I rarely think to water it, but it's only grown at about half the rate of the potted ones.

Wow, really helpful advice, thanks all!

Now that the tree has arrived and I can see how very small it is it's obvious that I can't plant it directly in the large planter yet - it would look ridiculous if nothing else!

So I shall pot it up in stages to make sure it's happily contained. Great idea to put the pot in the planter with some other things around the edge and gradually let the tree take over as I pot it up.

I'd also got a little confused over the differing types of compost suggested online, so I think I'll go with half ericaceous and half mp compost, and avoid tap water 'cause it's really hard down here.

Thank you!