If they're shastas, cut them to the ground. New growth will only come from the crown of the plant.

If you can post an image, we can help you ID them.

Thanks Jean. Here's one photo from this past April, and one today. If I cut them now, any idea how long to be fairly filling an area again? (Note that the photos are on Webshots. I've attached here in forums before but this time couldn't see that option, directly)

Here is a link that might be useful: Webshots album, last 2 most recent photos

That looks more like an Osteospermum fruticosum kind of flower. Shasta daisies look like this, more or less:

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Here is a link that might be useful: picture of Osteospermum fruticosum

Yes, I think you're right! Thank you. Well at any rate, they're being cut back - hope they'll come back okay!

They should be fine. Keep in mind that they are a cooler weather perennial in your area, and may not show their stuff in the heat. Don't worry, fall comes and they come back well.

You're hoping you have osteospermum, and it will come back.. believe me it will ! I planted a few about 4 years ago and every year trim it back, but its so invasive that I want to get rid of it and find this is impossible
Thought I had dug it all out last year, but it's coming back thicker than ever. So, I'm digging again ! Anyone else have experiece with this?