This is the question I was asking myself today. I am beginning to plan for my gardening for this upcoming season. I have a 4 x 10 plot at my community garden. I want to grow different types of peas this year: shelling peas, sugar snap peas, and snow peas . Last year, my sugar snap peas grew really well (that is what is in the picture at the top). For this year, I am going to put up two trellis side by side, but I wanted to check first if I would have any problems with growing different types so close by. From what I found online, the only problem I could have is if I am planning to save the seeds for next year, which I am not planning on doing. A lot of plants if they cross-pollinate you wouldn't see anything until the next generation. Corn is an exceptional to that, so you never want to plant different varieties of corn near each other.
Peas are a cool season crop, that can be started before the last frost of the season. I live in zone 5, so I can expect to be planting my crop in April with a harvest in June.