"Repel" is a misleading word. If a daylily (deer's favorite food) is planted right next to a Salvia, that deer will most likely still eat the daylily down to tiny little daylily stubs. It will however pass up the Salvia. Sort of like having chocolate and liver on the menu. Which would you go for? (-:

I have bog sage planted with another deer resistant plant, helianthus angustifolius (swamp sunflower). The deer are munching the sunflower a bit, even though the salvia is intertwining. The deer don't eat any of my salvia.

I have tested a garden phlox 'Robert Poore' this summer by placing it in the middle of deer-resistant plants such as salvia greggii, coneflowers, crape myrtle, spirea. It worked well through June-August and then they found it and munched it.

Hope this helps,
Cameron

Here is a link that might be useful: my latest deer resistant plant report