Although they cannot take summer heat they do need some warm days to put on growth. T think yours will be ok in the next couple of weeks, and you will see a spurt in growth. Al

Is it true that they don't transplant well?

You need to plant in November. They grow all winter then really shoot up when the days get longer in early spring. Mine bloom from about early April through most of May if it stays on the cool side, which is not too often in Dallas! Buy the kind that say "early bloom" or "heat tolerant" and I bet you'll get flowers next spring. Check out the web site for Fragrant Garden. I've had good luck buying from them and they send you instructions for different parts of the country.
Good luck!

zone 7 should be doable. flowering period might be short.

here in Cali, there was so much rain in the early Spring that sweet peas are a couple weeks behind normal growth.

yet, flowers are popping now. so far, pink, purple, cream and a cream with a purple tint on the edges. and the scent. that's what I'm talking about! bouquets come soon.

I live in z7 Middle TN where we have had lots, & lots of rain & cool weather. My peas were planted in the end of March & are now starting to bloom. I didn't do anything in particular for them except put in plenty of mulch & worked it into the soil because I lots of clay. I'll post a picture when I can. Try some different varieties. Mine are from Seeds of Italy & I saved seeds from my peas from last year.

Mine still look really sad, and I think it is too late to start over. Oh well! I'll have to wait until next year.

Bouquet, I think our winter is too severe here to start them in November. We can get snow and pretty low temperatures. Don't you think that would be too tough for them? Maybe I should plant them in February outside?