Question
I am looking at planting some lavendar but get overwhelmed by the number of different species available. Which one(s) might be best suited to the extreme heat of TX summers and an occasional dip below freezing in the winter?

Answer
Hi Steve,
Thanx for your question.  I noticed you are between Austin and Houston so I hope this information will help you.  There is a lavender farm in the Texas Hill Country and they grow Lavandula intermedia or Provence Lavender.  Most lavenders are pretty drought tolerant and heat tolerant but will still benefit from a weekly deep soaking.  The provence lavender is more suited to the heat and semi-arid climate than an English lavender which might suffer although I would think that the standard lavenders will do well as they do just fine in our hot, humid Kansas Summers which can go weeks without rain and still survive a below zero couple of days every winter.  So, I'd go with the provence lavender but I would also give Lavendula angustifolia or the standard lavender a go to because I think it will work in your climate too.  Here's an article from Texas A&M Cooperative Extension you may find helpful.
Tom

http://aggie-horticulture.tamu.edu/ornamentals/Cornell_Herbaceous/plant_pages/La...