|Are there any varieties of crape myrtle that are hardier than others. I live in the lower half of zone 6, and would like to have a variety that makes it through the winter without dying back to the ground. I do have a protected spot in front of a brick wall that will get sun from noon 'til sundown.|
|There are some hardier varieties developed by the national arboretum, but in my experience it can still take them several years to build the strength to withstand winter without dying back to the ground, especially if the first few winters are severe.
For this reason, it requires some patience to get them going to where they reach their full potential. Also, these plants leaf out very late in the spring, so there is often a temptation to think they have died back when in fact they are just very slow to bud out.
To give them the best chances of surviving, providing wind protection and several inches of organic mulch over the root zone (do not place it against the trunk) are about all you can do. Do not fertilize it late in the season as this might encourage late growth that will not have time to harden before the cold weather and will consequently cause extra die back.
Surprisingly, in some cases heat reflecting off a building on a western exposure can actually cause more abrupt temperature swings within the plant during the winter (especially if there is snow to intensify the sun's heat). Also, winter wind coming out of the west will hit the solid building and then roll backward giving the plants essentially a double smack. So, it might be better to site it in a sheltered lawn type area or surround it with other plants to avoid that reflective potential.
Your local nurseries and county extension should be able to help you identify the varieties with the best chance of success in your yard's microclimate. You might also be able to identify some by observing plants growing successfully in your neighborhood or under very similar conditions.
I hope this gives you some ideas.