Latitude and its effect on bloom times

Thu, 28 Jul 2011 20:52:34 PDT
Mike, Hi!

In California, the south to north trend for first blooming is the typical
one. In winter, however, I have seen cases where some species bloom earlier
further north on account of the earlier arrival of rain. I am referring to
bulbs planted out that rely on rainfall, of course, not hand-watering on a

Here in San Diego, Bloomeria crocea was finished by mid-May, Gladiolus
tristis by the end of April. Amayllis belladonna is going full bore right

San Diego, CA (at 300 feet or 90 m)

Nhu, your "what's blooming" project is already teaching me some interesting
things.  Flowers that Mary Sue and Jane report in bloom now (Bloomeria
crocea, Gladiolus tristis) are long since dormant here, with the last of
their seed pods drying out and cracking open.

Mary Sue's about 200 miles north of me, and Jane is 500 miles.

We've noted before how the Amaryllis belladonna season starts in southern
California and moves north.  It sounds like that also applies to other

It would be really useful to know what exactly triggers the different
growing times.  Maybe temperature?  Day length?  I doubt it's just water,
since I keep watering my pots until the plants tell me that they want to go

It would be helpful if people could post their altitude along with their
location when they say what's blooming.  If temperature is the controlling
factor, gardeners at higher elevations but the same latitude should see
later blooms.

San Jose, CA (min temp 20F / -7C) (about 500 feet / 150m above sea level)

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