I use a lot of half double crochet 2 together (abbreviation is hdc2tog) in my patterns also. This is just two half double crochets in the same stitch. Making one hdc, I don't pull through the three stands but instead make another single wrap and insert it in the same stitch. I yarn over, pull through the stitch, yarn over and pull through all five strands on my hook.
Finally, I needed a little larger knot on some stamen for the Columbine flower. For this I used a 4 hdcCL stitch. Again, I made 4 unfinished half double crochet around the chain (instead of in a specific stitch), yarn over and pull through all the strands on the hook.
Again it is closed with a simple slip stitch which makes a wonderful little Clones type knot on the end of the stamen.
The final stage to finish the stamen and spurs of the Columbine Flower design is to slip st around the chain that the cluster stitch is made on.
Now I use the chain as a padding cord. Instead of single crocheting in each stitch I single crochet around the chain the number of times specified in the pattern.
I love Irish crochet and have found that many of the techniques work really well with larger thread and yarn and comes out beautifully. The Columbine flower is so beautiful and I just had to see if I could make something in crochet that would look close to the original flower.
I hope this tutorial is helpful and that it encourages others to not fear using Irish crochet techniques. It really is just crochet with some embellishments.