plant_lover_grow, here and there, I have had the opportunity to confirm that the above-ground parts of a plant weigh roughly the same as the parts
below ground.
Therefore when I see a plant appearing to outgrow its container, I visualize a root system that is growing and gradually displacing the potting medium almost entirely. Indeed, I have 'unpotted' a few plants to find a mass of roots and just a smattering of the medium. The regular routine of indoor plant care over a long time appeared to have had a "reverse bonsai" effect. Instead of restraining growth and development, the routine had settled into a "hydroponic" program.
There is a credible school of thought that one can create a living sculpture by manipulating the light, water and fertilizer environment.
I used to know one interiorscape technician who practised this with great success.
So, if you wish to keep the Schefflera in a container outside, recognize that you have very little control over conditions of light, temperature, humidity etc. But you can manage its above ground growth - somewhat - by root pruning and fertilizing... judiciously!
You can also prune away the top growth to maintain the size and shape that appeals to you.
It has been demonstrated that pruning the 'roots' and 'shoots' simultaneously, stresses the whole plant enormously. Once again I think of the adverb "judiciously".
As for the sago palm (Cycas I am thinking), options are limited. I suggest that you anchor the container; a piece or two of rebar forcibly driven vertically through the container and into the ground will serve admirably. In the meanwhile you can look around for a suitable replacement BUT!...
Beware the viciouscycad scale

plant_lover_grow, only after I looked at my post on the forum, did I realize that you had addressed it to Al.
In which case courtesy dictates that I should have deferred to Al.
I apologize to you both for the culpable lapse in forum etiquette.

That's quite alright, ronalawn82, I'm open to suggestions from anyone. I addressed it to Al/tapla, because he's the one that usually responds to my container gardening questions, but good advice is good from anyone that gives it.