I would not plant perennial clover in the spring in NC. Folks further north my get away with it and if lucky, others may get away with it too, but it is not the best practice. Here is why: Perennial clover is slow to establish. It spends a lot of time establishing a root system after germination. When you plant it in the spring, it is competing with annual weeds starting from seed that are in your soil bank. The weeds (mostly annuals) are faster to get going so the get ahead of the clover. Also, in the south especially, the summer weeds are favored by hot dry conditions in the summer. You end up starting with a fairly weedy plot and things deteriorate over the life of the plot and you spend a lot of money and time on herbicides or the plot is relatively short lived.
I like Durana for the south. It is slower than most to establish but once established it is very drought tolerant and very persistent. When you plant perennial clover with a WR nurse crop in the fall, the WR takes off first. It becomes the attractant that first fall. Deer love it when it is young and tender. It becomes less attractive as it gets older. The perennial clover germinates in the fall but doesn't really grow much before winter sets in. The following spring, the WR takes off and crowds out weeds. It also has a chemical effect on weed seed germination. This allows the clover time to establish a root system. When they WR hits about a foot or so, mow it back to 6"-8" depending on conditions and the type of clover you select. This will not kill the WR but it will let enough light in to release the clover. By summer, the WR will die on its own and the clover will fill in. This reduces the opportunity for weeds to get established in your clover.
All clover fields will get weedy over time. That is not necessarily a bad thing. Starting with a clean field planted in the fall will give you the most years of deer food in the long run for the lowest cost.
Thanks,
Jack