'Lamarque' is probably going to be better suited to your climate, and will likely make a better plant in the long run.

However, that depends on whether the 'Sombreuil' you're asking about is the true Tea (shrub form) or the "Sombreuil of commerce", which is a large flowered Wichurana Climber. If you're considering the real 'Mlle. de Sombreuil', then you could choose either. But 'Lamarque' will be a significantly larger plant than 'Mlle de Sombreuil', which will potentially be too small a plant for an 8 foot arbor.

Sombreuil climber will grow way too big for a 8ft arbor. They both do well here. You prob want Lamarque but it can also get large in the south but you can keep it in bounds easier than Sombreuril CL.

Teasing Georgia is a great FL rose. It stays healthy and blooms heavily.

Atmore Lamarque is at Rosepetals nursery in Florida. Mine is doing great here. It is a clean nonvirus carrying clone.

I gree with everyone. The modern large flowered climber (aka Colonial White), which we let do what it wanted to do, climbed up our three story house to the roof, and then made longer canes which drooped down from there. IMO in a warm climate it would eat an 8 foot arbor in about a week. Also, it has stiff canes, and horrible thorns (although its blooms are astoundingly beautiful), so it is difficult to prune. Lamarque is growing nearby in our garden, and is much more mannerly and easier to deal with. fyi, Lamarque also grows here in partial shade.

Jackie

My Lamarque is also a very large rose, though certainly not as large as Sombreuil.

There are two different roses called Lamarque in commerce. The so-called California Lamarque and the Atmore Lamarque. At one time there was a discussion over whether these were difference clones of the same rose or actually diffierent roses. I do not know whether this was ever resolved.

The Atmore Lamarque is the one I grow, and I understand it can grow 8-15 feet in height. I have it growing on a six foot fence, and have to prune it hard several times a year. I've never let it get to 15 feet, but I can easily see that it might.

This is in zone 9b California