Hi there,

You should still have enough time for the plants to establish if they do not arrive until late August early September providing all the plants are perennials. Annual plants may not have enough time to complete their life cycle to produce seeds for the following year. It looks like the species listed are perennials. I would suggest that you follow the planting guides suggested. We also have more information at Barnyards and Backyards if you have questions, http://www.uwyo.edu/barnbackyard/. 

If you have more questions please let me know. 

Thanks, 

Brian Sebade