praying mantis

I use to have lots of praying mantis.  I used systemic rose food for years, and now I have no praying mantis.  I stopped using systemic in spring of 2017, and many of the good bugs have returned, but no mantis.  Should I be patient, or buy Praying mantis in the garden store?  If I should buy them do I wait for spring?  I know lots of people buy lady bugs, but heard most of them fly away.  I do have dishes I try to put water in.  Unfortunately it's so hot and dry in the summer, the dish is dry more often then not.  Are there other things I can do to restore the balance.

You can collect some mantis egg cases to hatch in your yard, but they won't stay if there aren't a lot of other bugs to eat.
Build a bug oasis and they should show up.