The Icicle Hitch is a very secure slide and grip knot that may grip on tapered pole.
In August of 2009 Practical Sailor reported on their testing of slide and grip knots. Their analysis concluded:
“… On more modern line, which tends to be much more slippery, the rolling hitch often slips under load. It may also fail to hold on wire or stainless-steel tubing….”
After testing various knots, they recommended the Icicle Hitch as offering the best performance as a Slide and Grip Knot. (Animated Knots)