I've only grown snow peas (which I think is just another name for sugar/snap peas.....unless you mean the diff between sugar snap peas and oregon sugar pods........one is flat and one is thicker/rounder). But my snow pea plants are about 4-5' tall, whereas I think plain peas are only about 1-2' tall.
I hope I haven't confused you!

Some snow peas have colored blossoms, while English peas and snap peas are almost always white. Snow peas have extremely flat pods while the others will be rounded. All three types comes with vines ranging from1 ft tall to 4-6 feet. If you know the variety, you could judge by the vines, but otherwise not.

Thanks, Catherine. I probably should have been more specific about what I'm growing. I planted:

Burpee's Sugar Daddy (podded pea) No height is given on the seed packet (that I can see). Online info ranges from 2 feet to 4 feet.

Seeds of Change Sugar Pod 2 Snow Pea (eat pods only) 24-30" tall

Burpeeana Early Pea (eat peas only) I don't see anything about height mentioned on the seed packet here either. What's with Burpee? (Or what's with my eyes?) Online info says 24".

American Seed's Dwarf Gray Sugar Snow Pea (eat pods only) 2.5 feet tall

Good to know, Farmerdill. I found some colored flowers out there!

I made a similar mistake last year, and my advice is, label your crops in the future. I was not able to tell snow peas and sugar snaps apart, and when I harvested the sugar snaps (?) early to try and use them for snow peas, they were often tough to the point of being inedible.

I think some snow peas also have white blossoms, but you might be able to tell crops apart based on blossom color, so if you still have the packs for those seeds you can try to reference that, or internet search the varieties. Otherwise, you might be out of luck.

I guess you might have to consider this a learning experience...

I did the same thing this season, my first for peas. While I did label the rows well, I'd didn't space them far enough apart and once each variety reached the top of their trellis they began to grow into one giant mass of peas. I harvested everything in flat pod form just as or before the seeds were forming. Turned out good, but in the fall I will space them further apart.

Your dwarf gray sugar snow peas will have purple blossoms...that's the easy one for me to tell early on.

The others you list should all be white flowered.

The pods on the Sugar Pod 2 Snow Peas will be flat for quite awhile and the seeds will show though as small bumps. Pick them before the seeds grow large and the pods become rounder since the pods will be tough by then.

The Burpeeana Early Peas will have pods that do not stay flat for long and do not show small seeds through the pod. Of course you want to leave this growing until the pods fill with good sized peas.

I'd have trouble telling the Sugar Daddy Snaps from the Burpeeana's but since both are picked with rounded pods you can try them and see which has the fibrous pod.....BINGO...that's the Burpeeana and the other should be the tender snap pea, Sugar Daddy.

In my garden, heights have not always agreed with the reported info. And some keep growing aller for a longer time and the height when flowering begins changes alot.

Oops, just visited my pea patch and looked a bit closer. The flower color info in my above post is okay but the pod descriptions isn't so good. The small seeds forming in the snaps and garden peas also show through when the pods are small. They look very much like the snow pea pods...so please ignore that part.