Agapanthus africanus ssp. walshii

Rodger Whitlock
Sun, 27 Nov 2011 10:35:31 PST
On 26 Nov 2011, at 14:34, Kirby Fong wrote:

> I bought three of these at a University of California at Irvine arboretum
> plant sale years ago... One has survived.  It is located about 10 feet east
> of the trunk of a camphor tree and within the drip line.  It has formed a
> small clump with three or four flowering scapes each summer.  In my climate,
> it is green year round.  This is a Mediterranean climate where it rains in
> the winter.  I water it in the summer. This is U.S.D.A. hardiness zone 9,
> specifically 37°40´18.95�N 121°47´14.60�W at elevation 458 feet.  This
> is in northern California.  Since UCI is in southern California, I would
> imagine most of the Agapanthus africanus ssp. walshii from their plant sales
> are in southern California, in or near Orange County.

Stealing ideas from various other people, I've developed a very interesting way 
to graphically compare climates in different places, and applied it to a 
comparison of Livermore and Steenbras, where this agapanthus is native.

To summarize: Both Livermore and Steenbras are Mediterranean climates, with dry 
summers and wet winters. Livermore gets a little cooler in the winter than does 
Steenbras, but the summer temperatures are about the same.

Precipitation is another issue altogether. Steenbras has 5-15mm of 
precipitation monthly, year round, wetter in winter, dryer in summer. Livermore 
otoh has bone dry summers and extremely wet winters. Taking all in all, 
Steenbras experiences much less seasonal variation in precipitation.

It would seem from this comparison, that in Livermore Agapanthus africanus 
walshii would need protection from winter wet and enough water in summer to 
keep it from total drought.

Re that graphical method:

Find climate data for the location you are interested in. Google is your 
friend; try googling "climate tbilisi" to find climatic data for the capital of 
Sakartvelo (to use the Georgians' own name for their country).

Set up an X-Y chart, with monthly average precipitation, in mm, along the Y 
axis and monthly average temperature, in degrees Celsius, along the X axis. 
Draw the curve using a smoothed line, and mark the months on it.

Put two such plots on one chart and you have an instant climatic comparison.

For bulb fanciers, draw a straight line from (0,0) to any point where the 
monthly precipitation is twice the monthly temperature in the units 
recommended. This line represents, approximately, the boundary between drought 
conditions when transpiration exceeds precipitation.

Credits: for the drought line, Hans Roemer, a botanist here who is a very 
skilled bulb grower. For the general chart layout, "Hythergraphs" from the 
1950s "Climatic Atlas of Canada."

I have a 47Kb example of such a chart, comparing Victoria, Algiers, and Batumi 
(in Sakartvelo), that I am willing to email to anyone who wants a copy. Note 
that it was prepared using Open Office, not Word.

Rodger Whitlock
Victoria, British Columbia, Canada

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