Source plants: many (Lowes, Mountain Valley Growers, etc.) 2017-2018
I have tried growing lavender for many years (with failure) on mounds, good drainage, bad drainage, lots of water, little water, etc. The plants always die during the main heat of summer. I just figured that our summer heat is just too much for lavender. And it is .... sort of.
Until I started doing some searching, I thought that lavender is lavender. And it's not, and it turns out that there is a big difference in heat tolerance. The most common lavender you find is 'English Lavender' (Lavendula angustifolia). It is the iconic lavender with the long flower stalks and small but graceful leaves. When you see lavender for sale, 90% chance it is this species. This is the kind that I have been (trying to) grow for years with no success.
The species of lavender that you are interested in if you are tying to grow in Phoenix is Lavendula stoechas. This is more commonly called 'Spanish Lavender' and is a very different lavender indeed. Another name for it is 'rabbit-ear', because the flower stalks have these funny little pink petals that stick out the top and look like rabbit ears. However it does not look like the classic lavender (in fact when I first showed this to my mom and told her it was lavender, she said "that's lavender ?!?!" fairly incredulously). It does not have long flower stalks, nor does it have graceful leaves. It looks more 'weedy' with tighter smaller leaves that grow a little haphazardly. The flower stalks are short. But I personally attend that they smell just as intensely lavender-y and the bees absolutely love the flowers in the spring.
I plant mine right in the ground (the heavy clay old farmland ground in most neighborhoods) with no amendments or special drainage. I don't water the plants directly (I think this is the key) but it gets incidental watering from the flow-through of a nearby pot. They made it through summer with no problem at all.
1+ year old Spanish Lavender flowering in the spring
