Silver Birch Jacquemontii

I am considering planting a few trees at the top of my garden which may in the future provide a little screening. 

I don't know a lot about trees but these sound like they will be a good choice because of shape and the fact that they are attractive and will not block out too much light because of leaf size.

My plan is to plant three in a line, about 3m apart. Is this going to work for this type of tree and what sort of size do they grow each year?

I just popped into my local garden centre and they do have some at a great price of £25.99 and they look around 7ft+, although they may not be the finest specimens! I'm not sure how they should look in a pot closely lined together but will they come into their own once planted up in the garden?

Photo below of the garden centre Jacquemontiis.