But my space is mainly roses, and I read this thread with hopes of new ideas! I do see alyssum looking nice with roses. Oh yes, lambs ear. But it requires cleaning up after. Mushy leaves under the plants harbor pests. My best option is the Walkers Low Catmint.

Bordering a couple of the beds are either bulbs or SB Daisy

On beneficials, I have spent a bit of time mapping out which veggies are good next to each other AND what flower/plant either brings in a good bugs or drives off the bad. I picked the society garlic, because gophers are supposed to hate it. We put it in along the fence line with the neighbors brick pile, good cover for gophers. A gopher dug a hole up to one side of the row of garlic, walked through it, and dug a fresh hole on the other side...not what we wanted but, once those garlic get big and established, maybe the gopher will head a different direction.

We also use the calendula and poppies, Nasturtiums, comfrey, marigolds, geraniums, etc for similar purposes. Mint is supposed to be good, but keep it in a pot! Heather is supposed to chase off white fly, this has been a dud so far.

This warm winter it seems everything under the cover, except the roses, and night crawles, looked like the worms went dirt tracking under there, took a real beating.

I was rushed for time, trying to beat the rain, which was too bad as on a deep black surface like that, every weed that had survived stuck out like a zit, but I simply did not have time to dig them all out.
As it is I failed and ended up digging the roses out of the black muck in the rain.
The only tool that works if you do not want to ruin the roses is ones bare hands.

The problem with having to cover the roaes is finding what companions tolerates that, that is not unwanted.

I am not, repeat NOT, going to bury them again as workng in our black-gumbo is too much a pain in the buttocks in the spring.
I put strings on them to find them but the strings either rotted or were so soaked in black mud, I could not find them.
I actually think what ever the string was made of was candy for night crawlers as the few I found when pulled were no longer attached to anything and about half as long as they once were.
I also think one is still buried but will just wait till a sprout pops up to locate it.
The ones that did best were the ones so stiff that canes poppped up out of the dirt so they were easy to find, but up-righting them was not hard because I had to dig up the rose, but I had to dig a hole behind the rose to upright it.
I have done this more than once before but this was the worst of the worst, in a year when it should have been very easy.

The Oxalis comes from seed pods but I am worried the Straberries took a real hit.
It took four years for them to cover one fourth of the rose bed.

Society Garlic is exactly the same. A yard wide strip of it will not prevent nor repel gophers. They will dig under it, through it, walk through or around it. Guaranteed!

Amaryllis belladonna, narcissus, joquils, none of the bulbs "poisonous to gophers" will repel nor prevent gophers. I had one dig under the clump of belladonna on the hill, using the bottoms of the bulbs as the roof of his entrance. They won't EAT it, but they WILL dig right through it.

Many salvias are the same, they won't eat the roots but they will dig through them. They're doing it out back here, right now. The only thing which will prevent gophers are wire baskets. They will burrow around them, under them, eat the roots which grow through them, but they can't get into them, so the crowns of the plants are safe. Kim

I also plant short ornamental grass specifically to encourage the preying mantises to travel to the roses. Anything upright and the right color would probably do, but they don't use the clover to hang out in. The ladybugs also use the blades of grass a lot, I've noticed.

Oh, I also have a bunch of spiders in there. Don't use my suggestions if you aren't a real nature lover, lol.

I use the grass in rhythms/geometry to give a bit of formal structure to the garden, too. My roses tend to be so arching or rambly :) I like the white-variegated grasses, and so do the mantises here.

I know what you mean about the gopher weed, I hate those things and guess the gophers dont eat the root of the weed, but they sure do not mind digging just past it.

I would love to screen off the property from the neighbors gophers, but it would really take both of use to dig a good trench, we are raised, so easier from their side than ours.

I am trying to "feed" this gopher...

One year I planted scabiosa (pincushion flower) here and there and was shocked to see how many aphids loved those plants. I got an idea to plant them near roses that the aphids seemed to love. Sure enough the aphids preferred the scabiosa which were closer to the ground.

Also keep in mind that thrips love light colored flowers so that they can hide in plain site. Light colored flowers like small iris and Easter lilies etc... can attract those pests as well.

No plant is going to prevent leaf diseases like black spot or rust. I have found that here in semi-arid So Cal, removing lawn helps, because lawns release a lot of moisture into the air of the immediate area, moisture that fungal diseases need to thrive. Of course in an state with high summer humidity, like Georgia, Louisiana, it's so humid anyway that lawn removal would probably not help.

Some people say earwigs don't eat plant growth. I totally disagree. In my yard I can count the amount of bugs/insects on my fingers. And the only culprit I can point to are earwigs. They are always hiding nearby plants that they have preyed upon. Not to mention, I've had traumatic events where I've cut spray of roses and sniff them only to have them crawl out over my hands and nearly onto my face! Now I am cautious of cutting/picking any flower with small, semi-perfect circles cut into the petals.