Can I use something besides silicone sealant for garden art?
Yes, there are other glues including E6000 and E8000 that are also useful for making garden art. Have a look at this Glue Resource Guide for Garden Art Projects for more recommendations. People in really humid areas like Florida have a hard time keeping whatever product they use from becoming too warm. When adhesives and sealants get too warm, they separate into a gel-like liquid and that does not work properly. I have not had any problems with GE Silicone II here in Canada where we have cold winters and humid summers.