I started everything in seed flats and began planting out late last year. For me, it's been very labor intensive. Slugs devastated the the Layia and only those in containers survived. The gardener in charge of the native section at the SF Botanical Garden has had similar experiences.
Tidy Tips is early in nature, but Limnanthes douglasii (Meadowfoam) is earlier. I obtained meadowfoam seeds late, so it will be late in my garden too. Slugs haven't bothered my meadowfoam, which is also true for the Botanical Garden.
Two other species taking serious slug damage: Collinsia heterophylla and Linanthus grandiflorus.
Species they haven't touched: Phacelia campanularia, P. tanacetifolia, Platystemon californicus, Gilia tricolor.
Species that fall somewhere in between: Nemophila menziesii, N. maculata.
Apparently, before San Francisco was built up in the 20th century, it was quite the place for wildflowers. The book San Francisco: A Natural History quotes noted California plantswoman Alice Eastwood:
"In the 1890s, the open country everywhere around San Francisco was a beautiful wild flower garden in the spring. In the region near Lake Merced the wildflowers were so thick that it was impossible to avoid stepping on them."So it's nice to connect to that in my garden--if only a little bit.