I'm looking for a small tree or large shrub that has yellow or variegated foliage. It will be growing next to a mature Diablo Ninebark and behind a seagreen juniper. There is a medium sized oak that partially shades this spot, but it still gets sun most of the day. I'm in zone 5A.

I considered using cornus alternifolia 'W stackman', but I haven't read very many good reviews and it needs too much shade. I'd like something in the 10-15 foot mature height range. Can someone recommend something that will work here? Thanks.