Bulbs flowering early (was: Mild winter)

Nathan Lange plantsman@comcast.net
Wed, 05 Feb 2014 14:36:38 PST

While I have never been one to monitor the timing of blooms (i.e. 
epicuticular wax), the flowering times for many cultivated spring 
flowering plants are significantly ahead of schedule across Northern 
California. Moraeas and Romuleas both undoubtedly flower primarily in 
response to vernalization. The accelerated accumulation of chilling 
hours across Northern California this year is the likely cause of 
their early flowering times:
The recent mild day time temperatures in January were very deceiving 
since the night temperatures were consistently far below normal, and 
the nights are much longer now and in January. Many recording 
locations are well over 100 chilling hours ahead of last year, 
another above average year in chilling accumulation. Even though 
these data do not represent soil temperatures, they are very 
indicative of vernalization accumulation. If anything, these data 
grossly under estimate this year's true vernalization accumulation 
since air temperature hours below 32F (0C) are not counted. Although 
the optimal vernalization temperature and duration can significantly 
vary from species to species, it's all relative. Everything is going 
to get vernalized sooner and therefore flower sooner this year in 
Northern California.

Of course, I'm only talking about flowering plants that have access to water.


At 10:26 AM 2/5/2014, you wrote:
>About a month ago, My wrote to the list asking if bulbs were blooming early
>this year in California. I wrote back saying that everything here in San
>Jose was on schedule.
>My, I apologize. I was wrong.
>Although my fall-blooming stuff was on schedule, many of the spring blooming
>bulbs are now blooming a month or more ahead of schedule. The spring Moraeas
>are now starting to bloom, and several spring Romuleas are in full bloom.
>Most of these would bloom in March in a typical year.
>I don't know if the cause is the dry weather we've had for much of the
>winter, or the milder average temps (other than a nasty freeze at the end of
>last year), or something else. But definitely stuff is blooming early.
>Back in December I was worried that the freeze might actually delay
>blooming. Shows how much I know ;-)
>Is anyone else seeing early blooms this year?
>San Jose, CA
>Zone 9, min temp 20F (-7C)
>pbs mailing list

More information about the pbs mailing list