Hi Deb
This is one of the more modest & mannerly Teas.
It would probably get to approx 5' x 5' over time if given its head, but it's not difficult to keep it quite a bit smaller by regular dead-heading and gentle shaping.
David Ruston had a group of these planted together and kept trimmed to about 3' high in the front row of a border at Ruston's Roses, and they looked absolutely wonderful.
Araluen Botanic Park near Perth are planning to use 'Marie Lambert' as a front border in a new rose bed too. They wanted a compact rose with healthy foliage, reliable repeat bloom and good fragrance for the purpose.
The foliage is a real asset - - healthy, compact (especially when regularly trimmed) and the dark colour does show the lovely pale blooms to best advantage.
The fragrance is lovely too.
It doesn't have any bad manners that I know of Deb. The only plants I've ever seen of this that don't look impressive are ones that are pruned like HTs each winter. (They spend the following year trying to re-establish their lovely twiggy shrubbiness just in time to get whacked to three main stems again the following winter!!)