By Susan Lewitt, for Let’s Talk Plants! December 2022.
Going to Seed?
Is it better to start with potted plants or seed in your garden?
I have better success with seed than with young plants with some species. I have grown several different plants in a small area and some were both from seed and seedlings. I found plants started from seed thrived, while the seedlings, in the same area, struggled. Was this because the roots of the seedlings of plants grown from seed took more quickly to the area where I planted them verses plants grown in pots? Some of the plants that I have grown from seed are California Poppies, Narrow Leaf Milkweed and Purple Chinese Houses, but my most successful one has been white yarrow.
Three yarrow species are native to San Diego:
One, Common Yarrow, Achillea millefolium, comes with lacy white flowers. Another is Golden Yarrow, Eriophyllum confertiflorum, with bright yellow flowers. A third, a yellow flowering species, Eriophyllum confertiflorum var. confertiflorum, is not as widely available.
All three occur in the wild, from San Francisco to San Diego. Common Yarrow accepts a twice-a-week watering in the summer while Golden Yarrow is okay with only once monthly watering in the summer. Both can be grown in full sun, but Common Yarrow will grow in part to full shade. They both do best with low moisture and can be grown in medium to slow draining soil. They may be dormant for part of the year. About a hundred and one native plant nurseries, have Common Yarrow, while the golden one is available at thirty-seven native plant nurseries.
What should you look for in California Native wildflower seed packets?
If you’re shopping on Amazon or in a nursery or other stores and you come across a delightful packet of seeds that says, “California Wildflower Mix”, please read the label carefully because some of the seed vendors slip in nonnative species in the mix and others do not understand the definition of California Native Plants. You may find Shasta Daisy seeds in there which are actually European. For clarification on what is a native plant, here is the definition used by Las Pilitas Native Plant Nursery:
“A native plant is a plant that evolved in an area before modern humans or their animals wandered through... In California, that's somewhere between (the years) 1400 and 1500.”
Therefore, a seed company that claims some of its species are native because they have been naturalized here since 1905 is not very accurate. It takes hundreds of years for plants to evolve together.
It is easy to be tricked into thinking a California wildflower mix has native seeds because in the packet you will find actual natives such as California poppies, White Yarrow, Clarkia, Arroyo Lupine, Baby Blue Eyes, Evening Prim Rose, California Bluebells, and Catchfly. However, if you read closely, the packet may also contain such nonnatives as Shasta Daisy, Coreopsis, Black Eyed Susan, Flax, Sweet Alyssum, Gaillardia and too many others. When asked, some native seed companies have said that the reason these species are included in California wildflower mixes is because the USDA plant database actually lists those plants as native. Indeed, the USDA labels many naturalized species as native thus confusing the matter!
One way to ensure that you get native seeds is to make sure the label says California Native Seed Mix, not California Wildflower Mix. Check the packet listing and look up the plant names on websites such as Calscape and Calflora. A better seed source is to go to a local native plant nursery. The best seed source for San Diego seeds and bulbs is California Native Plant Society, San Diego Chapter (CNPS-SD). On the CNPS-SD website you can access a great variety of native seeds and bulbs which may be purchased by mail. Many of these are locally grown in San Diego and harvested, donated, processed and shipped by our generous and thoughtful members. https://www.canativeseeds.com
Here are some resources and guides that will help you with your seed selection: This Calscape link (https://www.calscape.org/loc-32.7157,-117.1611(San%20Diego)/?&poploc=1) has information on the needs and appearance of our many San Diego native species and whether they can be easily grown from seed. Calflora, https://www.calflora.org/search.html, will tell you if a plant is native, nonnative, naturalized or invasive and in the case of natives, its natural range. For Calflora, you need to know the exact common name or the botanical name. A recommended book available from CNPS and Amazon, is Seed Propagation of Native California Plants by Dara E Emery, a paperback revised as of June 15, 2021. It tells about seed preparation and propagation. It also has an extensive list of native species if they need special treatment and when to sow them.
And you never know that whether you start from potted plants or seeds, you may get native plant volunteers that help brighten and fill your garden with natural beauty and some native pollinators too!