Bloom Predictions

Life Cycle of the Annual California Poppy

Because it takes a week, or more, to first detect seed germination, it’s best to wait a couple of weeks before looking for growing plants.  The first stage of seed germination is the beginning development of the plant’s root system; being underground, undetectable.  The next stage is the growth of the plant’s cotyledons which are the first structure that emerge from the soil.  A week or so later, the young plant’s first true leaves start to develop. 

Poppy cotyledons are interesting structures.  Each developing plant has a pair of gray green (similar in color to the plant’s stems and leaves), unique forked cotyledons that grow to approximately 1 inch in length.  Once an observer is trained, they are fairly easy to find when they are near fully developed.  I liken the cotyledons to batteries because, unlike true leaves, they don’t need photosynthesis to generate the energy required by the plant to continue to grow.  Having done their job once the true leaves develop, the cotyledons wither and die.

The non-native, invasive filaree has one of the highest plant densities on the Reserve.  Although not proven, it is possible that filaree is a major competitor to the native poppy plants.  If marginal rainstorms trigger more filaree seed germination, the growing plants will draw minerals and, possibly more importantly, water from the soil reducing subsequent poppy seed germination and growth.  More developed, and taller, filaree plants might also shade smaller poppy plants again impacting their growth.  This is an area that calls for more investigation.