If you like to fold some other interesting Origami Hydrangea models, you could just try to fold the Hydrangea Cube. The Hydrangea was designed by Shuzo Fujimoto (diagram can be found in his book of tessellations), & the closing of the cube was discovered by Meenakshi Mukerji. You can find the instructions for the cube in her book “Exquisite Modular Origami“, p. 69. This modular project combines 6 same sized Hydrangea tessellations into a 3 D cube. If you don’t want to fold 6 more tessellations, but are still interested in another Origami Hydrangea project, you could just fold the Hydrangea Box.
I always like a challenge, so I folded my Origami Hydrangea Cube from 5 cm / 1.9 in Kami paper. The finished cube measures about 2 cm / 0.8 in and has 4 levels of Hydrangea tessellation. You can make any number of levels and any size. You will have an easier time folding and assembling your project if you choose regular Origami size paper (15 cm / 5.9 in).
I looked around quite a lot to find some information about the locking mechanism to the Hydrangea cube, but did not find much about it. I then just played around with my papers and found the solution myself. See if you can also find the solution?