Clematis alpina

I have never been very successful with growing clematis. Too many slugs? 
The only one that has lasted is this alpina. It grows up a white beam tree which keeps it safe from slugs, but it prefers life at the top so I rarely see it! However a stem fell down last year and is now flowering at head height, and isn’t it lovely?
I have planted a yellow ’tangutica’ next to it so fingers crossed that will develop too.