mortar colour

If you're starting afresh, use white cement. However, the sand will have more effect on the colour than the cement, and most bricklaying sands are rich in fine iron ore pigment. You could use a rendering sand instead, but it will be harder to use for bricklaying. There are more silver coloured sands too, but I don't know what they're like for bricklaying or what they cost.

The other important thing is the bricks. Strange though it might seem, you need significantly better bricks to build a garden wall than you do to build a house. Walls get soaked both sides and have no heat leaking through to dry them out, so they are much more vulnerable to frost damage. This means you need to use bricks with low absorbancy, and your old bricks may be unsuitable.

lime and white cement produce a similar color. I would tend to use white cement myself, coupled with lots of 'bow ties'.. if you use cement you have to stop movement, as unlike lime, the mortar cant take movement without cracking.

The resultant colour is the sand colour washed out..round here we have yellow wand, so its a pale buff.

If you gave us more idea of the mortar colour and close-up appearance...

Only comment to add is that old soft bricks and cement mortar are a bad combination. Yes it works, but when the cement eventually fails it tends to pull off the edges of the bricks with it. Once that happens, its an inevitable downhill slide for the bricks. A lime mortar would be better, probably moderately hydraulic.

NT

its never the cement that fails. Its the old soft bricks.

Thanks for the tips.

The bricks in question, though oldish, are hard and I have not seen frost damage in them locally, even when used in garden walls.

I will get hold of some silver sand and try some mixes.

It's too cold to use lime cement in the winter, it wont set properly i thin