Experts and BHG readers answer.
Planting Flowers in July in So Cal
Thanks for writing. If you're able to keep your plants well watered after planting while they get established, you can plant pretty much anything you want. The key is really to keep them from drying out as they get adjusted to your garden.
I'd start at your local garden center or nursery and see what plants are still available for sale.
Good luck! I'd love to see pictures when you're done!
---Justin, Senior Garden Editor, BHG.com