Published by Brian Wagner on 11/2/25 in “Growing Flowers from Seed.”
Primula bulleyana (commonly called Bulley’s primula or candelabra primula) is a magnificent species of candelabra primrose native to higher altitudes in southern China. It has tiered flower whorls arranged along the stem – which are golden, yellow and a tinge of ruddiness.
What is truly stunning about this perennial is that it flowers in the middle of summer. Also, it prefers the dappled light or part shade of the garden, which makes it even more special. Its ruddy golden orange flowers almost glow in the shade.
In its native geography of southern China, it is happiest – and thrives – where the ground is moist, such as beside moist streams in montane forests – and it’s also very content at the forest edge. Understanding that its primary and secondary ecosystem preferences are riparian and forest edge, means understanding where it can be happy in the garden: part shade and moisture are its friends.
Growing from Seed
Almost all Primula seeds, regardless of the species, have a non-deep physiological dormancy – and if you remember earlier posts regarding this type of dormancy, you’ll remember that these are weak dormancies that are often broken with the passage of time. If you let the seeds dry out for 3 to 6 months, they’ll germinate at least 50% without needing cold stratification.
Also like most Primula species, Primula bulleyana seeds do not last very long – and if you keep them after a year they’re likely to be dead. Like most Primula seeds, they should be used within 12 months after harvesting.
With this species, the research studies are limited, but they have confirmed the ideal germination temperature to be between 20C (70F) and 25C (80F), but don’t go below or above this. They must stay somewhere in this sweet spot (Thompson, 1970). Also, cold stratification is likely to improve germination (Deno, 1993) – and I suggest 2 months at 4C (40F). Because the seeds are quite small, it’s advised that after cold stratification you remove the seeds and let them dry out for a few hours before sowing them. Seeds can be dried out temporariliy like this in between cold stratification and sowing, without difficulty. But, don’t let them dry out for too long – and, if any have started germinating already, they will not tolerate drying out or they’ll die.
Seeds need light to germinate (Hitchmough et al, 2011; Thompson, 1970), so don’t bury the seeds. Also, if you can, provide cooler nights – around 10C (50F) if possible (see the Thompson 1970 study). When nights are cooler than the days, these are often referred to as oscillating temperatures (or alternating temperatures) in the scientific literature – and which are known to provide a boost in germination for some species of plants (not always, but some species yes). You can do this by cracking a window at night in the room where they’re germinating.
These are not fast growers, and they will need potting up around Day 75-90. They will not flower their first year unless you can provide mature seedlings with a 3-5 week period of cold (winter). Like many perennials, their first winter is what triggers them to ‘bold’ (i.e., flower) in their first spring.
References
Deno N. First Supplement to the Second Edition of Seed Germination Theory and Practice. 1996. Self-Published. Available online by the United States Department of Agriculture at http://naldc.nal.usda.gov/catalog/41279
Hitchmough J, Innes S, Mitschunas N. The effect of seed treatment and depth of sowing on seedling emergence in Primula species. Seed Science and Technology. 2011 Oct 1;39(3):539-51.
Ma YongPeng MY, Tian XiaoLing TX, Zhang JingLi ZJ, Wu ZhiKun WZ, Sun WeiBang SW. Evidence for natural hybridization between Primula beesiana and P. bulleyana, two heterostylous primroses in NW Yunnan, China. Journal of Systematics and Evolution. 2014; 52(4): 500-507.
Nikolaeva MG, Razumova MV, Gladkova VN. A Guide to Germinating Dormant Seeds. Nauka, Leningrad: 1985. [Translated in part by Rosbakh S, Baskin CC, Baskin JM. Nikolaeva et al.’s reference book on seed dormancy and germination. Ecology. 2020; 101(7)]
Rong WA, Ke-hang MA, Bin FE, Yong-qi MA, Chang-xing LI, Yin JI. Seed Germination of Four Species of Wild Primula. Subtropical Plant Science. 2019 Sep 30;48(03):243.
Thompson PA. Characterization of the germination response to temperature of species and ecotypes. Nature. 1970 Feb 28;225(5235):827-31.