To grow sweet peas in your yard with any kind of success, these rampant, floriferous vines need to have a large frame or trellis to trail up, hook onto and bloom from. And creating your own needn't cost anything.
If there is one think I love doing in my garden, it's making supports and trellis from the natural materials I already have. I like to build a wigwam-style frame for my sweet peas, as it creates that quintessential, abundant cottage garden look in my cutting patch when they begin to flower.