Dodecatheon 2023

[Robert]

Dodecatheon is a genus of plants predominantly, but not exclusively, of North American origin. Here in California botanists have lumped the genus Dodecatheon into the genus Primula. I use both names in an attempt to provide some clarity to the exact species I am referring to.

A number of Dodecatheon species are native to the region close to our Sacramento home. Native populations of Dodecatheon hendersonii can be found growing on our Placerville property.



Some seasons thousands of Primula (Dodecatheon) hendersonii can be seen blooming on our Placerville property. Most of the plants are sterile, perhaps triploid, or aneuploid. I hypothesize that their origin is that of hybrids with perhaps Primula (Dodecatheon) clevelandii var. patula, which is also native in this region. Since the California gold rush of 1849 there has been a great deal of habitat destruction. Many surviving plant populations have become isolated, and in some cases become their own ecotype.



At higher elevations, in the California Transition Zone, most populations of Primula (Dodecatheon) hendersonii are completely fertile and bloom about a month later in the season. The plants from this elevation retain their late blooming characteristic when grown in our Sacramento garden. This provides us with a prolonged blooming season with this species.



Higher yet in the Sierra Nevada Mountains another ecotype of Primula (Dodecatheon) hendersonii can be found that blooms two months later than the form found growing on our Placerville property. These plants also retain their characteristic of blooming later in the season in our Sacramento garden. This extends our blooming out another month. In addition, these plants are completely fertile and inter and intra specific hybrids can be created with these plants.



Pictured is Primula (Dodecatheon) hendersonii growing with another California native species Ranunculus occidentalis var. occidentalis. This plant combination is seen every spring on our Placerville property. Currently I am attempting to recreate this combination is our Sacramento garden. Progress is being made. I now have Ranunculus occidentalis hybrids that are tolerant of summertime irrigation in our Sacramento garden. This is another topic to discuss later. Anyway, I enjoy growing Dodecatheon species immensely and hope to share more photographs of both species and my hybrids as the season progress.

[Robert]

The first Dodecatheon (Primula) hendersonii plants will be blooming soon. These plants are derived from a 2017 accession in Colusa County, California, elevation 1,584 feet (483 meters). I have other seed accessions from this area and all the plants tend to bloom at the same time and are fertile.



Dodecatheon hendersonii from our Placerville property blooms a few weeks later than the Colusa County forms. The plants growing on and in the vicinity of our Placerville property are mostly sterile. They appear to be triploids. Like seedless watermelons, when they are pollenated by diploid or tetraploid plants a few fertile seeds are produced.



This batch of Dodecatheon hendersonii seedlings are derived from a 2019 seed accession from 5,105 feet (1,556 meters) in the Sierra Nevada Mountains, El Dorado County, California. The plants growing in this area are fertile. The plants also bloom about 6 to 8 weeks later than the Colusa County forms.



This batch of Dodecatheon hendersonii hybrids was planted in the autumn of 2021. This is their first season to produce true leaves.



This batch of Dodecatheon hendersonii hybrids was planted in the autumn of 2022, only a few months ago. During their first season of growth the newly germinating plants only produce cotyledon leaves. It is hard to believe that the tiny seedlings can go dormant when the dry summer weather arrives, be kept dry all summer, yet vigorously emerge during the winter and produce true leaves. This is reminiscent of the desiccated Lewisia rediviva roots that survived the Lewis and Clark expedition, only to come back to life when the expedition finally arrived back east after being gone for a number of years.

[Robert]

The first flowers of Dodecatheon (Primula) hendersonii are now opening. My accessions from Colusa County are the first to start blooming each season. Clones from our Placerville property will start opening a few weeks later.

Seeds of other species were sown a bit late this season and are still being stratified in the refrigerator. This was never necessary when we lived on the Placerville property, however this is frequently a necessity here in Sacramento where adequate chilling hours are not always reliable.

[Diane Whitehead]

This has always been one of my favourite local wildflowers.  We call them Shootingstars.

 There are about 400 to 500 species of primula already, so they don't need to steal dodecatheons.

Diane

[Robert]

 There are about 400 to 500 species of primula already, so they don't need to steal dodecatheons.

Diane

Hi Diane,

From a horticultural perspective your comment has a great deal of merit. From strictly a horticultural viewpoint I believe that the Genus Dodecatheon is better served by being considered a distinct genus separate from the genus Primula. For me their unique horticultural characteristics and potential are better served detached and considered separately.

[MarcR]

Names and name changes are decided by the International Botanical Congresses.
Within the International Botanical Congresses, there has always been contention between the 'lumpers' [who want to recognize as few distinctions as possible' and the 'splitters' [who want to recognize as many distinctions as possible]. I believe that often ego, rather than science, drives the results. In any case the botanists on the International Botanical Congresses are often more concerned with academic considerations than how gardeners will be effected.

[Robert]

Hi Marc,

Yes, there is too often a great deal of unnecessary controversy in the academic world of plant taxonomy. As per my personal investigations of what we might refer to as the genus Dodecatheon, a great deal of study and taxonomic revision needs to be made. Fortunately I have a few priceless friendly contacts within the academic world that are not interested in controversy and competition. My understanding of plant taxonomy, genetics, and biochemistry has expanded greatly due to their insightful direction and advice. This has greatly assisted my progress in my horticultural R & D and helped enhance the beauty of our garden.

[Robert]

The Colusa County forms of Dodecatheon (Primula) hendersonii are now in full bloom. As the colonies have increased in size I have been planting them out in various locations in our garden to get an idea of their tolerance of summertime irrigation. In a shaded xeric (no summer irrigation) portion of our garden I planted out several clumps. They all broke dormancy and grew well this winter. Unfortunately, all but one clump were destroyed when we repaired our broken fence this January. A week ago I have planted more--both in summer xeric locations as well as in locations that receive various degrees of irrigation during the summer. The plants have taken well, so now to see the results next spring. Dodectheon hendersonii has a large geographic range in Western North America. I look forward to testing accessions from the most northern portions of its range in the future.

[Robert]

The higher elevation forms of Primula (Dodecatheon) hendersonii are blooming in our Sacramento garden. This seed accession was planted in December 2019 and the resulting seedlings are blooming for the first time this spring.



The higher elevation forms of Dodecatheon hendersonii trend to have shorter scapes and bloom about a month later than the lower elevation forms found in both the Sierra Nevada foothills and the Inner Coast Range of California.



I have been experimenting with Dodecatheon hendersonii in the open garden in locations that receive small amounts of summertime irrigation. This species performs best without summertime irrigation, so I am attempting to ascertain the degree of tolerance this species has to summertime irrigation.

One approach to achieve summertime tolerance to irrigation is to cross Primula (Dodecatheon) hendersonii with species that thrive in moist environments during the summer such as Primula pauciflora, P. tetrandra, and/or P. jeffreyi. Fortunately, in some forms of each species the chromosome numbers match, increasing the likelihood that viable, and hopefully fertile, hybrids can be created. Currently I have a batch of Primula pauciflora seedlings coming along. During the summer I can gather pollen from Primula jeffreyi and P. tetrandra and store the pollen in the freezer to use the following spring. As other mesic species continue to develop these too can be worked into this breeding program. Progress will take time, however I will keep reader up-to-date on my progress.