There are a dozen or more different kinds of serviceberries, both shrub and tree. Some shrubs get to 4ft, some to 25 ft. Tree forms get from 10 ft to 40 ft, depending on species. You will need both latin names of the shrub you bought, then you can search that name to see which one you have. The most commonly sold serviceberry is Amelanchier arborea, usually a multistemmed shrub that gets to 20 to 25 ft. It can be trained as a tree but will tend to send up root shoots. A. laevis, Allegany or smooth Serviceberry is a nice tree form getting to 30ft, if you can find it. Return to the nursery, ask for the latin name and ask them how big it gets. Below is a link to various serviceberries, click on any picture and follow the info to the bottom of the page where there will be more links, at least one will have ultimate height. Here is a link that might be useful: Service Berries

I also have seen reports that 'Smaragd' Emerald Green do not go brown in the winter. There are some other arborvitae cultivars which are reported to brown in the winter. That person may have gotten the Emerald greens confused with those cultivars. It, also, could be that in your area the Smaragds get so stressed in the winter that they do turn brown. I have a screen of thuja 'Green Giants' which all winter stay a nice color for me situated on the north side of our neighbor's two story house. But my friend has a 3 foot high row of the same cultivar of my trees planted along the south side of her 7 foot tall privacy fence. Her trees while they were trying to get established did change color last year. Not exactly brown, but more of a burgundy shade. They greened back up the following spring and summer, and we are still waiting to see if hers will stay green over the coming winter.

if the soil around the newly planted things is still thoroughly moist ,can they do without my watering them? ==>>> if the soil is moist.. you should NOT be watering them .. water when needed ... not on a schedule .. do not water again.. until the soil dries down to 2 or 3 inches ... insert finger.. and find out ... fall and winter watering .... is very much less than summer ... mostly because.. for most of us... there simply is NOT enough day heat.. to draw the water out of the soil at depth ... and you didnt list heat as a variable.. so good you asked ... and we check below soil surface ... because that is where the roots are ... and we really dont care if wind dries the first inch or so ... if you dont have mulch ... you really have to insert finger.. or use a hand trowel ... to figure out.. how it works.. in your italy .. in your climate.. in your micro climate ... all we can do.. is highlight the variables... and you have to figure it out ... if.. in my MI ... with ground freeze ... if i plant in october .... and water deeply ... i might not have to water again.. until next may ... [snow melt and heavy mulch] .... but it took me a few years to figure that out ... just like you will ... bottom line.. too much water.. might be worse than too little ... if you rot the roots off.. its dead ... whereas.. if too little water.. many.. many trees... will cope ... soooo... dont kill them.. with too much love ... is how i like to sum it up ... ken

I was thinking like 10-15 ft tall and about 7 ft wide. Something that will fill in that area as a screen. I'll try posting on the shrub/tree forum later today if I can. Thanks!