Dodecatheon identification

[Leena]

I have grown D.pulchellum and D.jeffreyi from seeds and have mixed up the seedlings by mistake  . Some died last winter, but some flowered last summer, but I don't know which one this is.
Are there any differences in leaves or flowers in D.pulchellum, D.jeffreyi and D.meadea so that I know what to look next summer when trying to identify my plants?
Any idea which one the plant in the picture is?

[Robert]

Hi Leena,

Here is a link to a botanical description of Primula (Dodecatheon) jeffreyi, a species native to California. With additional research you may be able to identify the Dodecantheon species in your garden, presuming it is not a hybrid. I hope you find this link helpful.

https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=98397

[Leena]

Thank you Robert,
I will have to compare this with the description. It is difficult to find descriptions which compare species with each other and tell the differences which I should pay attention to.
I have fallen in love with Dodecatheon, and hopefully a white one will flower next summer.

[Robert]

Hi Leena,

I am happy that the link might be helpful, or at least a start in the right direction. The Dodecatheon pictured in your posting is beautiful and so well grown! I too enjoy growing Dodecatheon species, however currently I am limited to the low elevation California species that are dormant during the summer and thus are unharmed when temperatures reach 43 to 46 C. These temperatures seem to be our new summertime “normal”. I will keep trying with some of our local native high elevation species. No luck yet. Dodecatheon are certainly well worth growing in our gardens.



Our locally native Primula (Dodecatheon) hendersonii growing in containers in our Sacramento, California garden – Spring 2022.

[Diane Whitehead]

Photos of two species in Wildflowers of the Pacific Northwest by Mark Turner and Phyllis Gustafson:

Dodecatheon jeffreyi leaves look narrower than those of D pulchellum

[Robert]

Primula (Dodecatheon) jeffreyi blooming in the Sierra Nevada Mountains of Northern California. This species is generally found growing in moist meadows in subalpine regions of the mountains.



Primula (Dodecatheon) tetrandra blooming in alpine setting in the Northern Sierra Nevada Mountains of California. Primula tetrandra and P. jeffreyi are very closely related to each other. Primula tetrandra is a much smaller growing species, however the two species can and do hybridize with each other in the wild. In some cases this can make exact identification challenging. Primula tetrandra is found growing in moist alpine meadows and at the margins of alpine lakes. Both Primula tetrandra and P. jeffreyi are extremely difficult to cultivate in low elevation gardens where summer temperatures are extremely high.

[Leena]

Wonderful pictures Robert. Especially the one growing among stones look so natural.
Moist meadow is more what my garden conditions are like than alpine meadow, so I should think D.jeffereyi would do ok here.
D.tetrandra and hendersonii are new names to me, maybe not hardy enough to grow here, do you think?

Photos of two species in Wildflowers of the Pacific Northwest by Mark Turner and Phyllis Gustafson:

Dodecatheon jeffreyi leaves look narrower than those of D pulchellum

Thank you Diane! I will compare the leaves in spring, and it is good to know D.jeffreyi leaves are narrower.

[Robert]

Hi Leena,

Primula (Dodecatheon) hendersonii is a low elevation, xeric species. It would certainly not be cold hardy in your northern garden and the dormant tiny rice grain tubers absolutely need to be kept dry during the summer. It is the perfect species for our low elevation garden here in Sacramento, California. Except in an alpine house this species would likely be very difficult to grow in Northern European gardens even if cold winter temperatures are not an issue.

Primula tetrandra is also referred to as Dodecatheon alpinum. It is indeed an alpine species that might be worth experimenting with in your northern garden. The plants in the photograph were growing among rocks at the edge of an alpine lake located above the timberline in the Sierra Nevada Mountains. Its growing requirements are very similar to those of Primula jeffreyi. I would consider both their habitats as hydric (flooded or close to flooded at all times).

In our part of the Sierra Nevada Mountains Primula tetrandra grows where the high peaks of the Crystal Range abruptly rise into a region where the free atmosphere at 700 mb strongly influences the atmospheric boundary layer. This profoundly influences the environment in which this species grows. Harsh, cold, desiccating winds can batter these exposed sites even in the summer and autumn when there is no snow cover. Currently the site where I photographed Primula tetrandra is covered by 4 meters of snow. The site where I photographed Primula jeffreyi is covered by 3.5 meters of snow. The snow cover, of course, insulates the plants from extreme cold temperatures. Both species are frequently found growing in cold air basins. During the autumn months before there is snow cover, the plants can be exposed to very cold, freezing temperatures, however freezing temperatures can occur during the early morning hours even during the summer. This year both sites will likely remain covered by snow into June or July. The number of snow cover days has been declining. This is impacting the habitats of many of our native plant species in a number of different ways. How exactly the various plant species will respond remains to be seen, however when the snow cover disappears earlier in the season hydric and mesic habitats can become very dry by late autumn. I have observed high degrees of plant stress during these dry periods. In some cases, there have been high degrees of plant mortality, however these ecosystems seem to recover to a degree when moist conditions return.

[Leena]

Robert, thank you!
It is interesting to read your descriptions where these plants grow in nature.
Here our "problem" in winters is that many times there is not much snow (about 5cm at the moment), but still temperatures can be cold and ground freezes deep. Snow would be such a good natural insulator. Winters have become milder though, and this year so far the minimum in my garden has been -19C.
In more northern and eastern Finland there is usually much more snow than here in south west of Finland. I am very happy that my Dodecatheon have survived.

[Robert]

Leena,

I have a keen interest in the genus Dodecatheon (lumped in Primula here in California). I started a Forum thread on this topic and hope to provide on-going detailed information about my experiences cultivating plants within this genus. How I integrate the plants into our garden setting is an additional aspect I wish to include in this discussion. Breeding and plant selection is another facet of my interest in this genus. I greatly enjoy being innovative with plants, to see how far I can expand their range of cultivation as well as developing unique novel varieties, especially ones that integrate well into our California garden. Many species are native to our region in Northern California. Writing about my observations of the various species growing in their native ecosystems also seems appropriate. I hope Forum readers find this continuing discussion informative. And, of course, I hope others will share their experiences and observations with their plants within this genus. This, too, will be very informative.