Question
How frequently do you refresh the rosemary sprigs you set out to guard against cockroaches? How frequently to you refresh the lemon gratings/peels to keep cats out?

Answer
Hi Eden;
I put new rosemary about every month to six weeks.
In the spring, when the kitties would start roaming more and start writing letters on my holly bushes, I buy a dozen lemons, make a big pitcher of lemonade or freeze the juice, for pies later, and chop the peels and scatter them. Then when I use a lemon, I chop the peels and scatter them, keeping in mind the grid I am following so the fresh peels go in a different spot.
I put the lemon peels starting at the front of the flower beds, and scatter back into the inner area as far as I have peels to scatter. on the theory that they will not cross the peels to get into the flower bed. Seems to work fine that way. I just do them on an ongoing basis.
The sprogs of rosemary I use are not really sprigs. I put just a piece of rosemary about 2 inches long on each shelf, but under appliances etc, I put a little bigger piece or strip the stems with my fingers and throw it in a sweeping motion under the appliance.
Under my vanities and kitchen sink, where the pipes come through the walls, I stick a little piece inthe hole beside the pipe.
Charlotte