If it is a case of a single night dip and then temps go back up then you can maintain 2-4" or mulch and use frost cloth or fabrics that are heavy but not heavy enough to break or bend the stems. Mind you, this frost protection is not really needed by Incrediball or Little Lime (LL) for frost per se. The only useful purpose in doing this is to prevent the leaves from getting zapped by the frost and then looking ugly for weeks until the plant leafs out again in 2-4 weeks. It happens to me when people visit after a frost and ask 'yuck, what happened to those leaves over there?'. Hee, hee, hee.

So, if you do not care about the leaves being zapped and waiting for new ones then do not worry much about the frost. It will not kill the plants as the roots will be protected by the ground heat, the deep watering and the mulch that you put around Incrediball and LL. Depending on how low temps go, there might also be a few stems zapped or the ends of some stems.

Flower buds should not be affected as there should not be any flower buds on your Incrediball and LLs yet. At worst, there may be a delay developing the flower buds and opening them.

I am aware this frost and sub-freezing temps will be a problem around Pennsylvania-ish. If you want to find out about when the chance of no more frost is likely, get the average date of last frost for your city online or from a reputable local plant nursery and then add one or two weeks (the date is an average after all). Also, weather.com has weather predictions for the next 10-14 days if you enter the city and state.