I made this cake a few weeks ago for a bride that wanted that rustic wood grain look, but didn’t want any fondant. I found that while the buttercream was nice and cold, I could use a small paring knife to cut in my knots. From there it was just making fluid lines around the knots in around the cake. The cake was getting fresh flowers at the venue, so I substituted some silk ones I have at the bakery as photo shoot stand-ins.
Jenniffer White, Cup a Dee Cakes - http://cupadeecakes.blogspot.com