I'm trying something new this year. For years, every Spring/Summer I've grown Morning Glories on a back trellis. The last few years they didn't do well. Too much rain, or not enough sun, too cool. If they did bloom there were hardly any flowers ... and they tend to bloom very late in the season up here in the Pocono Mountains of PA.

This year I'm trying Cypress Vine. Anyone grow these? How do they do? Thanks for any info in advance

Cypress vine grows wild here in Florida. I have no idea how it does in colder states

It's easy to grow, but a pretty dainty vine in that it is quite small overall and doesn't have the impact of other vines. Not that you shouldn't try it, but if I were you, I would have a backup plan. Like maybe plant both Morning Glories and Cypress vine, and if you like the CV better, then pull out the MG.

I've grown both Cypress Vine and now mostly stick to Cardinal Climbers, they're very similar, and I've never had a problem with either one of them. Cypress Vine has more delicate foliage and distinct star-shaped flowers, but I think the Cardinal Vine is a stronger grower and covers more area, and I always plant it for hummingbirds every spring, I start mine from seeds indoors.

Here's a link that shows both:
https://garden.org/ideas/view/...

And I agree with trying a mix, to be sure that whatever is limiting morning glories doesn't affect the Cypress or Cardinal vines the same way. That way you can see what really does the best in that area.

Agree with the others on cardinal vine. I grow it every year and it's vigorous for me. I've grown it in shade and in sun and it doesn't care.

Cypress vine grows well here in south Texas if it gets enough water. I agree that it is very delicate and does not get very big. The blooms are beautiful, but they are tiny. I did not plant them this year.

Cypress vine grows aggressively here...
In the vegetable garden...

When I first planted it on-site, it did very poorly... and the deer ate it.
But that was out on unimproved sand.

Difficult to imagine what the problem might be with the morning glories.... but I'd add some manure / compost and till the soil.

At my previous garden, those things were incredibly aggressive where I was trying to grow food.
Suggest that you try planting tomatoes after amending the soil... Cypress vines always seem to find my tomato cages... and smother the tomatoes, if I don't take drastic measures!