They like rich soil (unlike edible peas)so I make sure their site has had some compost or aged manure the previous fall.

I plant them about two weeks after I plant edible peas, which would be sometime in April--mid to late Apr. If it is cold, they take longer to germinate and start growing. Overall they grow pretty slow until things warm up. I usually soak the seed overnight before planting.

They really take off by June and start flowering then or in July. They don't like the hot weather, but if you keep picking them, they will continue to grow and blossom all summer. If you neglect them and they go to seed, they will start to look ratty and stop growing/turn yellow. Water them once in a while if it's really dry, esp. when they are young. They seem fairly drought-tolerant after that. The bouquets are wonderful because of their fragrance.

But if you have a woodchuck or something eating them soon as they sprout, there's not much you can do. Besides get rid of the woodchuck.

I had a woodchuck beat me to my shitakes this year...I will have to cage it well to keep his little contortable body out!