Luther Burbank successfully grew most (definitely L. humboldtii, L. parvum, and L. washingtonianum) if not all of these species in or very close to Sunset Climate Zone 14. What elevation range is considered "subalpine?" In California, L. washingtonianum can be found growing around 4000 feet, flourishing in Sunset Climate Zone 7, not exactly known for its cool summers. As with some California native Fritillaria, especially F. recurva, selecting the appropriate ecotype of native lilies to grow is likely one of the primary keys to success, with the exception of L. parvum. Unfortunately, it's not always as easy, not that it's ever easy, as just finding seed of the species you want to grow. Nathan At 04:30 PM 4/6/2015, you wrote: >Modesto, which is in the heart of California's Central Valley and >has adobe clay soils, might be too hot for some of these lilies, >especially L. washingtonianum, which is a subalpine to alpine >species. Lilium parvum is reputed to be the most widely adapted of >the species mentioned. Lilium bolanderi requires very good drainage >and is also found at higher elevations. I haven't grown L. >humboldtii, but have grown L. rubescens, which resembles a smaller >version of washingtonianum; it is native to the Coast Range of >northern California, where I've seen it growing on hillsides. > >Jane McGary >Portland, Oregon, USA