Without knowing your zone and general location, and whether you're talking about sun or shade, it's impossible to give you any advice.

Sorry--that would be super helpful. I don't know what I was thinking leaving out all of that pertinent information. Zone 7a. Mid Atlantic Region. Area is facing south--gets afternoon sun. i was thinking something that grows low but truly have no idea what I am talking about which is why I need you guys. THANK YOU AGAIN.

Geranium 'Biokovo' or Karmina' are both low groundcovers, take sun and moderate shade, bloom in late spring, are deer resistant, weed suppressing, and easy to control. Keep in mind that weed suppressing does not mean they will muscle out existing weeds; keep them weeded until they establish and then you're good to go. There may be others in your zone, but these two are good in my zone and at least through zone 5.

I just googled both of your suggestions. Both are very pretty. I am sorry to sound so dense but I am a novice (big time novice). I can plant this ground covers in between my existing perennials? I have hosta, day lillies, yarrow, salvia, roses, etc...

Maybe, they're not agressive. But your plants should be filled in, and the mulch is to help keep the soil moist, as well as to hold down weeds, and to feed the soil as it rots. I thought you were looking for groundcovers for a large area./

IME, no groundcover is all that efficient at keeping weeds at bay or certainly not to the extent that a good mulch layer does. And mulch provides other benefits to the soil which a groundcover cannot.

I would also suggest that a groundcover such as you are thinking of would work better in a woody planting area (trees and shrubs) rather than with perennials. But you can try some low growing perennials - generally not sold or marketed as "groundcovers" per se - to fill in between: Veronica peduncularis 'Georgia Blue', a sprawling type of hardy geranium like 'Rosanne' or 'Ann Folkard', or low growing sedums (stonecrops).

Personally, I like creating a living mulch from groundcovers. I find that Veronica prostrata, for example, creates a thick mat that keeps weeds at bay. Groundcovers