Shasta Viburnum Spacing
I rather impulsively purchased 3 shasta viburnums (5 gallon pots) to plant along a fence as a screen/hedge thinking that they would nicely fill in about a 20 foot length of fence. The tag at the nursery identified the shasta as having a mature size of 6' x 6'... sounded like it would fit well and since I love doublefiles, I was excited that I'd found something that would work for that spot. Well, after looking around online I see that the shasta will actually get much wider, more like 10-12' wide. I think I knew this at one time and that is why I had crossed it off my list, I just got excited when I saw 6' x 6'. I am now worried that I don't have the space for these and am frustrated because I feel like I was misled by the tag.
So, here's my question... can I squeeze all 3 of them in anyway? Should I just plant 2 of them maybe 6 or 8 feet apart? Just plant 1 and then get something else to fill in around it? I really want to screen the neighbor's yard, and I want the entire space filled, but don't want to crowd them too much (or the trees that they will be between). What is proper spacing for something like this when you want it to serve as a sort of hedge/screen?