Winter in Indiana can be very rough on plants. A lot of things play into whether a plant is hardy in Indiana, snow cover, wind and shade from winter sun.  Adjusting each of these can create a microclimate that allows a plant with a hardiness rating of 6 to grow in the area. Adjusting the zone of a microclimate is as easy as adding mulch, establishing a windblock, planting broadleaved evergreens in the shade, etc. Zone 5a has an average minimum temperature of - 15*F to -20*F

 

Summers in Indiana can be just as tough as the winters. Many plants can`t survive the heat and humidity that settles in Indiana around July.