Happy September, or should I say Seedtember! This month, we are celebrating all things seed at TPF. To say that 2023 has been a special weather year is an understatement. With rainfall way above average across Southern California, wildflowers proliferated throughout the region, creating vistas of unbroken color that plant lovers usually only dream about. We often praise the rain for these events, but that’s only one piece of the puzzle. Without a healthy soil seed bank, all the rain in the world would not produce those exceptional blooms of California native plants.
Late summer and early fall are usually a time when we can really appreciate that. At this time of year, in many of the most popular wildflower sites across the state, the spring blooms have set seeds, and the wind and sun have returned the once lush annuals to the soil, leaving a sparse landscape with little vegetation. The transition from such vibrancy to a dry landscape can give the impression of lifelessness, but that is a misconception. Under the soil, millions of seeds sit in wait for the cycle to continue again. Those dry summer landscapes are every bit as biologically rich as their spring counterparts.
This season is a little different. A rare summer storm dropped inches of rain across much of Southern California (including over 4 inches here at the TPF headquarters!) This is very unusual, and a lot of people are asking what that means for the native plants here. I’m not exactly sure, but can share a few observations. In La Tuna Canyon, where TPF is located, the hills are greener than I’ve ever seen. I haven’t explored them extensively, but on-site, it looks like much of that green is coming from the germination of non-native plants, especially short-pod mustard (Hirschfeldia incana.) This makes sense, as non-native species are more adapted to an opportunistic lifestyle, taking advantage of rains whenever they come. The good news is that with rain unlikely for at least a few months, there is a high probability that many of those seedlings will wither and perish. It may be that these rains will flush a portion of the non-native soil seed bank and perhaps help slow the march of invasive non-native plants in our wildlands.
In gardens around town, I have seen native annuals germinating. This is a curious case, and it will be interesting to see what happens. For those who are seeing this happen in their garden, I’d suggest watering those seedlings regularly until the rains return. They may bloom earlier than normal, or they may get extremely robust and bloom profusely at the normal time in spring. It’s hard to predict, but in any case, it will be fun to watch!
While high volumes of rain in the summer are abnormal on the coastal side of the mountains in California, there is one part of the state where this happens with some regularity. The desert, especially the deserts further east do regularly receive summer monsoonal rains and therefore have native floras adapted to take advantage of those rains. In past years, I’ve gone wildflower hunting during those seasons, botanizing in areas such as the Eastern Mojave Desert mountains, where summer rains can completely change those landscapes into verdant expanses of warm season native grasses, summer annuals and desert shrubs and perennials bloom profusely. I expect that will happen this year, and along with some colleagues at the California Botanic Garden, recently encouraged readers of the LA Times to take the less-beaten wildflower trail and look for the fall blooms in the desert.
Our Seed Department is using this incredible season as an opportunity to continue conserving rare plants for long-term genetic preservation. Last week, I had the pleasure of catching up with the Seed Program Manager Genevieve Arnold and Botanical Technician Ella Andersson as they cleaned seeds of Mojave Spineflower (Chorizanthe spinosa,) a rare desert annual. These seeds were collected for the California Plant Rescue project and will go into long-term storage to contribute to a genetic backup of botanical diversity throughout the state of California. In addition to that, they’ve been out in the field closer to home regularly, collecting local seeds to support our Local Source Initiative, which gives home gardeners access to first generation, genetically distinct, locality-tracked plants. If you’re interested in going hyper-local, keep an eye out for purple tags in our nursery, which list the geographical origin of our Local Source plants.
The Seed Department is also hard at work ensuring that gardeners in the urban core can create their own superblooms at home. I’m consistently inspired by imagining a future where wildflowers proliferate around the towns and cities of California. This will only happen if we embrace wildflower seeds as a major part of gardening and landscaping. One of the newest that Genevieve and her team have curated is called Urban Superbloom Mix, a seed mix specially designed to create a superbloom-type effect in the urban core. This is part of a larger “Superbloom” product series dreamed up by our Merchandise and Design teams (Yvette Corona, Hannah Perez, Jacki Hays, and Katie Tilford), which showcases and draws attention to the beautiful and mysterious superbloom phenomenon in California. They even built a webpage that includes information and resources to learn more about this unique event.
We’re not far off from the rains returning during their normal winter season, and as you’re planning for the upcoming planting season, I hope you’ll consider seeds as part of your fall planting plans. The wildflowers they become play an important role in our local ecology and the unique magic of California native plants. Happy Seedtember!