Native California Bulbs & Corms

Several years ago, when I felt that the basic structure of the garden was established, I wanted to begin to fill in the space between the larger shrubs. In the wild this would be called the understory and it would consist of a mix of grasses, herbs, annuals, and geophytes. The last group includes plants that arise from bulbs, corms, tubers, rhizomes and the like. So I set to work finding out where I could get bulbs and corms that are native to San Diego County.

I got off to a good start with some Wild Hyacinth, also known as Blue Dicks (Dichelostemma capitatum) in the Brodiaea family (Themidaceae). A friend of mine had a property with a ton of Dichelostemma on it, and he was planning to build something that would take out a big chunk of them. He allowed me to collect the corms, which was very easy. My soil was the same as his, so with no special preparation I stuck the corms in the ground and waited. When the rains came in winter, they took off.

As you can see in the above photo, the flower of D. capitatum is a dense umbel (cluster) of tiny lavender colored flowers. This plant multiplies and spreads itself readily by seed and by producing offsets from the corm, as shown below.

Dichelostemma capitatum is a great plant for the San Diego area garden because it is typically found in a variety of habitats throughout the region.

A genus that is quite common in coastal sage scrub and chaparral habitats in this region is the Mariposa Lily (Calochortus sp.). These are of course in the Liliaceae family. I have several, as shown below:

Unfortunately, I have lost track of what species these are. I feel terrible about this. The top one is probably Dunn's Mariposa Lily (C. dunnii) from the foothills and mountains of the region. The bottom one is almost certainly Splendid Mariposa Lily (C. splendens) which is fairly common in a variety of habitats and is the most likely species to have been present in Encinitas in the pre-urban past. The middle one is a complete mystery to me. I don't remember anything about it.

Another member of the Themidaceae family is Thread-leaf Brodiaea (Brodiaea filifolia). This is a somewhat rare and state-listed Threatened Species, but fortunately the corms are available from a few vendors. In the wild it is found near vernal pools or other areas with clay soil where they can retain moisture for a longer time. I have only sandy soil in my garden so I compensate for this by giving the Brodiaeas more frequent water, and this seems to work. I didn't understand this at first and wasn't getting any blooms because the plants would dry out too soon. Now, with supplemental water, I'm getting good flowers.

The last geophyte for today is Golden Star (Bloomeria crocea), yet another member of the Themidaceae. I only have one corm of this one, but it's really nice when it blooms which it is doing right now (May). It is slightly past its prime but still looking good. I'm hopeful that it will either produce offsets from the corm or produce some seed so I'll get more of them.