Grace, Golden Celebration is one of my favorite Austin roses. I've grown mine for about 13 years. He is gigantic, and I don't think in zone 10 your GCs will remain small for long. There may be nothing needed to give any height after the first year of GC's growth. Butterfly Bush might make things really crowded, in fact, and they don't stay green all year here, but go dormant just like a rose (I grow a lot of buddleia). I don't know how they would act in your zone. Do you have any photos you can show us? Here are a couple of my photos (sorry to those of you who have seen these before). These show GC and Boscobel. Diane

The middle photo is from a few years ago when GC was smaller. The last pic is shown with Augusta Luise which is a large rose herself, but GC is bigger. Diane

I love Russian Sage. It can hold it's own in situations like this and looks great year round.

I was thinking along the same lines as Sheila; gray foliage is so pretty with yellow and purple. I can also recommend Texas sage, or Leucophyllum frutescens.

I still think there won't be room for large plants behind Golden Celebration. And I doubt they would be taller than GC, either. Diane

Oh yes I saw golden celebration in Nashville all the way up the side of a building, at least 12 ft tall ?! I can’t imagine how it’ll be here for you . Now if you want a companion plant , I saw this and it popped into my head with your GC would be so beautiful!! I’m sorry I’m new to Ca and not sure if the leaves stick around or not .

https://www.provenwinners.com/plants/hibiscus/magenta-chiffon-rose-sharon-hibiscus-syriacus

I really want this plant ! :)

I grew the Lavender Chiffon rose of Sharon from Proven Winners for several years. It was OK and about the size of a butterfly bush. In my zone, it also lost its leaves and went dormant during winter. I think the size thing will be a problem with it, too. Remember that Grace has got three Golden Celebrations in that bed. Wowee. That could be a whole lot of rose! Diane

Oooooh lordy Diane and Lilyfinch I might have massively underestimated the final height of my GCs! This is their first year in the ground, and I was planning on them getting only around 5-6 ft (I guess I'm hoping i can keep them at that size with prunning....but maybe not?!)

I don't want them to be crowded. If I do add something, maybe a tall but skinny/narrow footprint plant to just add some color spikes behind them.....this larkspur would be sp pretty but it's too short.

This purple glory bush grows to 10' quickly and the color and evergreen foliage would be puuuuurfect, but it's too wide/shrubby I think to bed behind GC...

ooooooooh lilyfinch that rose of sharon!!! The color and flower shape are gorgeous! I'm not a fan of the paler colored blousy RoS, but I love the look of this variety.....great find! Let me get out the 'ol wish list.....

:)

Diane, thank you for posting your magnificent rose pics. I was tired from doing late pruning in my garden today, and your pics remind me why I need to do all the hard work in the garden. Can’t wait to see more blooms in the garden again. Helen

Thalictrum, or Meadow Rue, is tall and skinny and would fit behind the roses. Black Stockings is a nice one with long, slender dark stems holding frothy pinky lavender flowers, and probably the tallest variety. Mine were about 6' in this cold climate.

Clematis trained on a trellis would be narrow behind the roses, and wouldn't fill out until they are above the rose bushes. Purple clems intermingling with yellow roses would be stunning.

Can you give dimensions of the place for this plant?

Thalictrum and clematis are wonderful here, but they do not look good in the winter.

I agree with Sheila. Although meadow rue and clematis would look great, they don’t look good during the winter, not even in my zone 10a. Maybe try something like tall annuals behind Golden Celebration this year. You’ll get a feel for how large your roses will grow and how things look and fit behind them. Lisa

Oops, I missed the part about looking good in winter. Yes, thalictrum and clematis are weedy and brown during winter.

Is orlaya tall enough? I haven't grown it yet, except to test a few seeds over winter. (Lisa, they're still green, even after being buried under snow). It's used extensively in those to-die-for Japanese gardens.

Russian Sage looks so great year round. I guess I'm on a rant here, it is that great.

In your climate, I think your idea of Princess flower (Tibouchina) is a great one, with the color contrast between the golden yellow and the vibrant violet. The standard variety gets quite large though, do you want something 15 feet tall? There is a dwarf variety also, but that might be too small since you want something tall. Another option is something that would provide an evergreen background even if the flowers are not particularly striking, like Osmanthus, or Michelia figo (banana shrub), or Murraya paniculata (Orange Jessamine) whose fragrances might blend with the rose's. Or how about a Loropetalum or Phormium with dark burgundy leaves? You have so many tropical/subtropical options, that the challenge may be to combine them with the roses in a harmonious manner, rather than a disjointed way. Are you in zone 10a like California or more like Florida? That may help make a decision also.

Well I'm hoping my GC will get bigger than it is because 3 1/2' tall isn't very big, but I'm in z5/6 so we'll see this second year.

Lilyfinch - Rose of Sharon is a tree here. You have to work at keeping it to one trunk or you have a hedge that gets huge. I see the description of the one you like is 12' tall by 10' wide. Not a background plant. It has seeds that the birds and wind spread and sprout come up everywhere! It goes dormant here, don't know what it will do in a warmer climate. I planted a purple Althea last year which is similar to the hibiscus. Of course I can't find the tag right now so I can't remember how big it gets. Looking.....

noseometer, I'm in CA bay area - thanks for all the suggestions!

I think I've actually got the perfect idea - Alyogyne huegelii “Blue Hibiscus” trained into a standard form so it stays skinny and tall rather than round and wide - it's airy-ness and a standard form trunk will help keep too much crowded foliage away from the the roses to prevent disease (is the hope) but it's ever green, has purple for contrast against the yellow, and I love the flowers!

Perfect! Great idea!