If I own a small business and I wanna share my product with celebrities just to get customers and especially some of the celebrities I would like them to try my product is that close to possible ? How does it work? …

I would like to see if I can promote my landscaping business with them

Would need more information on this. For example, are you wanting to send your product to celebrities for free and hope that they post it? or are you wanting to send your product to celebs and pay them to post it?

If you are looking to send your product to celebrities then you can't do this with the expectation that they will post it, as there are no terms to this. The only guaranteed way is to pay them to endorse your product.