Yes, stores have difficulty stocking all the varieties of clovers. Some stores are more oriented toward forage, and will offer a greater variety than others. However, the tougher hurdle to cross is finding the variety or blend that matches your mission. No single variety of clover is going to:
1. Produce well in warm and cold season
2. Be palatable all year
3. Produce well on all sites
Crop varieties are selected for different traits, just like races of dogs. Yes, there will be some overlap of these traits between varieties, but in general, different varieties will perform better at different times of year, on different soil types, etc. There simply is no one variety that is best in all the categories you mentioned. To complicate this more, a single variety often performs differently from location to location, not to mention from drought to moist conditions. However, by selecting several varieties that grow well together, you can create a blend that meets most of your needs. I always prefer blends to a single variety when my mission is to provide quality deer forage throughout the year.
Growing Deer together,