Here in Phoenix, Arizona, it's really hot by the standards of most Oxalis until late October or early November. I oversummer most of mine in the house due to high summer heat and rain. A few Oxalis (and other bulbs) start growing in August, no matter what. If I put sprouting Oxalis outside then, they die. I've learned to leave them in the house, pale yellow-white and leggy, until it's cooling down at night. As a result hirta and meissneri are always leggy for me. They do bloom on the ends of the threads, and new growth will be tight. I wait to water the mid- and late-season bloomers until nights are definitely cool, late October or early November. I still haven't pulled them all out this year due to being really busy. But I've learned in the past that won't be a problem. Some don't mind being outside in baking sun and getting soaked a few times over the summer. This includes O. callosa, flava, obtusa and purpurea. Blooming today are a O. callosa, flava, lavender pupurea. O. hirta is done for the season. Obtusas are growing but no flowers yet. Most of the others just got their first watering with two big storms last week, almost 2 inches / 5cm total rain. That reminds me - I have some mixed O. obtusa seed from last spring to send to Dell. Leo Martin Phoenix Arizona USA