Can I make a sunflower in solidworks? or there is a better softwae for that kind of works?
If by 'make' you mean 'model' yes you can definitely model a sunflower in Solidworks. It would be best if every petal and other regularly occurring geometries could be identical, so you can take advantage of patterning.
If each petal needed to be slightly different, like a replica of nature, that would require hand building each bit which would be a lot of work in SW. There might be a better tool for a job like that.
So depending on what level of detail you require, it could be a 15 minute job or a 5 month job to model.
I agree with Robert's answer, yes you can model it in Solidworks.
Maybe that type of item would be more user friendly in maybe something like AutoDesk Maya or Blender or another? Either way, any 3d program you are comfortable using should be able to make.