QUESTION: PLEASE COULD YOU ADVISE - WE HAVE BEEN LOOKING AT BUFFALO GRASS BUT ARE NOT SURE WHETHER IT WOULD SURVIVE IN A COLD REGION SUCH AS MEMEL - NORTH EASTERN FREE STATE WITH WINTER TEMPERATURES DROPPING TO UP TO -13. ALSO WHAT TREES AND SHRUBS WOULD BE THE BEST OPTION THAT PROVIDE SHADE IN SUMMER AND LOSE FOLIAGE IN WINTER TO LET THE SUN THROUGH.

Buffalo grass has survived here on the premises this past winter when average temperatures were approximately -8C and -10C was experienced. Buffalo grass will yellow and slow down or stop in growth during winter but it will likely survive for you. I would advise you to try a test planting over a smallish area with the buffalo grass and see how it does for you during and after the upcoming winter.

Regarding your request of deciduous trees and shrubs for summer shade,  ideas include:

Trees (indigenous) – cape holly (Ilex mitis), river bushwillow (Combretum erythrophyllum)

Trees (exotic) – silver birch, maples (Acer palmatum and Acer buergerianum), Gingko biloba, , any of the ornamental fruit trees such as flowering cherries (Prunus sp.) and plane trees and liquidamber (Liquidambar styraciflua)

The latter two get very large however so avoid them unless you have a sizeable property.