How do sweet peas compare with morning glories in terms of growth, coverage, etc.?

Question

I plant morning glories every year in containers to climb up the walls of my terrace, but this year am having a lot of trouble with them. When buying the seeds, I saw sweet peas as well, and decided to give them a shot, and unlike the morning glories, they're doing great so far - I planted them later than the morning glories (less than 2 weeks ago), and every seed has sprouted and they look very healthy. I'm wondering if I should be planting more sweet peas, and how they compare with morning glories in a number of areas:

1. How fast do they grow, compared to morning glories? The number one priority is height/volume.
2. How does their coverage compare? Will they "branch out" as much as morning glories? ~6 morning glories in a rectangular 36" planter fully covered a 6' x 10' section of wall - would the vines from the sweet peas do the same?
3. Do I need to care for them any differently? I have read that they like colder temperatures. Is a New York summer too hot for them?
4. When (as in time of day) do they bloom? One frustration with morning glories is that the flowers are only out in the mornings, and at night when I'm actually there they are gone or shriveled up. I've never had any luck with moonflowers. Will the sweet pea flowers be open at night?

Thanks - I have had a hard time finding answers to these by googling, and the photos seem to be focused on the flowers and not the vines.

Answer 1

There are a great many kinds of sweet peas... But I haven't ever grown one that much hight than 24", I suspect that a sweet pea could fill up some spacial volume better than morning glory

Answer 2

Can't answer all of your questions, but I can tell you about my sweet peas. (Don't know what variety, sorry.)

I've got sweet peas on a fence. The fence is only about 4' high, but they would keep right on going if it was higher -- probably at least 8'. Planted just a handful in the ground (not a planter) last year and they grew in very thick. This spring they've come back, and brought friends. I'm in NH -- Zone 5, and summers almost never hit 100°F, really just expect to have maybe 2-3 days above 90°F.

I don't specifically remember that much about the timing of the flowers. I think they were open in the afternoon/early evening, but I don't remember about nighttime.

Answer 3

Just from my personal experience, ivy and honeysuckle have overtaken my yard. However, I would recommend Clematis and Passion Flower (Passiflora Cerulea is generally best for most of the US. Incarnata for the southern parts.) Sweet peas are pretty when blooming and easier to grow, but they generally are much thinner and more fragile vines with smaller flowers than morning glory and break fairly easily. Then you get the very noticeable pea pods on them which sometimes turn black. They remind me of vetch.