Wax begonias are tiny things compared with the Camellias. They're filler plants and their roots will have absolutely no effect on the shrubs. And the Camellias will grow very slowly in comparison. If that was my planter I'd put at least thirty begonas in it. Fill it right up. There won't be much else to look at after the Camellias have bloomed. Three begonias would be a sad sight in that space.

More to the point, the begonias are in the noise. Even if you do not have optimum conditions the camellias will outgrow the space, albeit a year or so down the road. I'm also concerned that you've nailed this together. 210 litres of wet soil isn't going to be kind to nailed timbers.

As to soil, Camellias prefer a moist, acidic soil rich in organic material. If your native soil is alkaline you'd save a lot of hassle by buying yourself a load of ready made ericaceous mix.

@floral_uk z.8/9 SW UK what you meant by "the begonias are in the noise"? And also should I put in as many begonias in as possible leaving some space around the roots of Camellia?

Good catch about the timber. Yeah nails might come out. I will put in some screws. If the timber starts falling apart the plan B is to nail more slats around it. Lol.

The timber is actually left over al-cheapo pine slats from previous project. It is treated pine and after looking it up it is H3 CCA Treated Pine.

CCA: Copper, chrome and arsenic

H3: Outside above ground, periodic wetting but where the timber can dry out; some leaching

I guess I will line it up with the builder's film which I have in plenty.

They do sell Professional Rose, Gardenia, Azalea And Camellia Potting Mix which does NOT have ericaceous written on it.

This is what is there on it.

• Boosted levels of iron and magnesium encourage healthy dark green foliage
• Controlled release plant food provides plant nutrition and trace elements for up to 6 months
• Includes next generation water crystals and coir peat for better moisture retention
• Professional grade wetting agent added for uniform soil wetting and prevent drying out

Use for potting up roses, gardenias, azaleas, rhododendrons, camellias and other acid-loving plants and adding to the garden soil when planting out into the open garden.

Will it do?

Yes. Ericaceous trees and shrubs are those that belong to the plant family Ericaceae. A key characteristic of these shrubs is the fact that they need acidic soil. The word ericaceous is also sometimes used to describe any plant that likes acid soil regardless of plant family. In that context, you could say that all of these are ericaceous plants: azaleas (or all rhododendrons), blueberries, camellias, cranberries, gardenias, hydrangeas, roses, etc.

Strangely, I thought 'in the noise' was a common expression. It is in our family. But on looking it up I find it doesn't appear to be. It means that someone is missing essential information by being distracted by unimportant background details, or 'noise'. The begonias are basically irrelevant because they would have no effect on the planting. You can put in as many as you like as close as you like. The roots are shallow and not wide ranging. You could put any small bedding plant in that situation. It's the camellias you should be concentrating on and the planter is not optimal for them. Apart from the issues with the construction and materials the main problem is that it is too small for two shrubs. Also, if it is to remain in that position, it's too close to the railing. The branches will grow through and get in the way. Is there a reason they can't be planted directly into the ground in the open garden? Is your soil not appropriate?

Reason: I noticed this comment at the beginning: "I have less than ideal conditions in terms of full winter shade and summer light till afternoon situation"

Just Started, the leaves of a camellia japonica that gets afternoon summer sun -at least where I live- do not survive/thrive unless I put some shade cloth to give it shade by 11am-12pm. However, during winter here, you can give japonicas full sun, morning sun only, afternoon sun only and even full but bright shade. Dense shade might be problematic when they are trying to flower though... but I have not tried dense shade in winter.

However, a camellia sasanqua could be in full sun during the summer here...

I would have chosen a sasanqua if it was going to get afternoon sun.

@floral_uk z.8/9 SW UK That is the toughest spot in my garden. Full shade in winter and in summers there is sunlight till about 12 PM. The area is a part of lawn. But the lawn over there is essentially dead. It is in slight depression and there is water logging when is rains in buckets. At least when it used to rain buckets in better times 4 years ago. Soil is as usual on the clayey side. Hence thought of putting in a raised garden bed.

@luis_pr The label said part shade and full sun. Hence I took it. I have a plan for summers. I will put my Osmanthus and Michelia Alba pots in front of it during summers. They will get direct sun till about afternoon. Worked like a charm during this year's aweful summers. So yes, there will be shade for these plants. What I am worried more is the fact that in winters there will be no sunlight for these guys. Just shade.

These ericaceous potting mixes are twice the cost of regular stuff. Can I just put in elemental sulfur in normal compost and garden soil mix. I recollect that it is slow acting over a period of 6 months.

Done!!! Next update when something dies. Lol.

Camellia have lobelia, sweet alyssum and heuchera for company.

Good luck!

Yes. Hope it goes well. Btw those are not what I envisaged when you said Wax Begonias. I understood you to mean Begonia x semperflorens which is smaller than yours. They look like Elatior Begonias.