Me Again --- I am in Zone 7a. Central MD

Therese grows to be a very large rose and I imagine especially in your zone where she will be tip hardy. When young, she tends to throw out more growth at the expense of blooms. You will probably get a few later in the year, but next year and beyond she will bloom very well for you. Not sure how she will do with repeat and mildew in your zone and area, but in a colder and more temperate area, she reblooms very well and doesn't mildew much, if at all.

Agree with everything the_morden_man said. I grow her and she does focus on 'growing' in the 1st year as opposed to 'blooming'. Once she settles in and starts blooming though, she'll bloom her head off. I once counted 35 buds on a 3 yr old Therese. Just be patient with her.

Meldew is usually not a problem with TB in MD, but BS can make it loose most of its leaves later in summer.
Olga

Rugosas are slow starters, but last forever. I haven't had much problem with blackspot on TB or any of my rugosas. But even if you do, do not spray. Rugosas hate to be sprayed.

Here rugosa hybrids can get BS pretty bad. Species (alba, rubra) and some less hybridized rugosas are quite resistant. Unfortunately TB is not one of them. Rugosas can't be sprayed with old oil based fungicides. Last generation fungicides like Banner Max, Bayer, Compass can be sprayed w/o any ill effect. I don't spray now, but did it for many years before. I used Banner Max and never even when it was 90+ degrees Banner hurt a single leaf on my rugosas.
Olga

I don't spray Rugosas here in Zone 6a. Therese will bloom at about 2-3 feet high, never fear, and I've never seen blackspot on her.

Here is a link that might be useful: Garden Musings blog on Therese Bugnet

Just curious how she did for you? I got mine at a bargain last year. She immediately dropped all of her leaves and I thought she was a goner. But she's back with her first flush of blooms. Very very pretty. I had to kill off the pesky caterpillars so I sprayed with an organic fungicide today. Before I read the rest of this post oops.....