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Re: California freeway "wildflowers"

On Fri, 17 Apr 1998 Doug wrote:

>To veer of the topic somewhat, I remember seeing a fragile potted oleander
>being grown in a bay window in Wales (in May-June) many years ago (it was
>little more than a twig). No doubt it was a challenging house plant there.

They can be, if grown in poor light on a north facing window, but
although not growing as impressively as those in the full glare of a
Californian sun, Oleanders can rapidly become quite large and outgrow
their allotted space as a pot plant even here.  I'm growing the
'common' double pink outside in the garden here on the south coast in
England and despite an exceptionally cold, northerly blast which
prevailed for the best part of a week, the flower buds continue to
swell and promise much for the months ahead.  It would seem that in
cooler climates with lower light intensity, Nerium has a tendency to
develop non-productive 'water shoots' if grown on a heavy or rich
soil.  I've grown and flowered a very lovely white form with
considerable success in the past, by ensuring it gets full sun and
planting it in very well drained - almost dry, rather poor soil. 


>I wish its grower could see the miles of oleanders when in full bloom. 

I was somewhat surprised to see very healthy and rather substantial
Oleanders in gardens close to the sea front at Virginia Beach
recently.  Their winters there are significantly colder than ours,
conversely it has to be said that the summers are often warmer by a
good 10F or  more.  Frost tolerance would appear to be at least down
to minus 5C - probably rather more judging by those at VA Beach.

>(Of course, I recall being very impressed with the miles of wild pink
>rhododendrons in England -- which are reviled as noxious weeds I believe.
>To me, rhododendrons are plants of great beauty since they are so rare in
>San Diego.)

Rhododendron ponticum is the bane of the south and west laying waste
to huge tracts of forest and native woodland.  Despite its undoubted
beauty, it has found conditions down here far too much to its liking
and spreads rapidly by suckering, self layering and seeding.
Virtually nothing can grow in the soil beneath these trees - the
slowly decaying leaves effectively creating a natural growth
suppressant with all other plants.  It is a serious weed creating an
under storey of impenetrable growth and suppressing all native,
woodland plants.

>(And of course, I was the weirdo who praised the yellow oxalis growing in
>the ice plant along the freeways in San Diego. I guess you have to see them
>there. I don't praise them elsewhere, though.)

There is always that most attractive semi-succulent species - O.
succulentum which produces masses of large, most attractive flowers.
However I do not know whether it can spread to pestilential
proportions, but I suspect it would not be unduly difficult to
eradicate.  It is the only one that I welcome, since its tolerance to
our cool, moist winters ensure that the plant barely survives, taking
up to mid June before it can regain growth lost to winter wet.

I'm surprised why Crepe myrtle - Lagerstroemia indica, is not grown as
a highway divider.  Granted it is exotic to CA, deciduous and
eventually quite vigorous, but it lends itself well to 'pollarding'
every few years and there are several most attractive colour variants.
It would also appear to be rather tolerant of traffic pollution, but
I'm not sure whether it could cope with full, unmitigated LA 'fug'.

David Poole
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