Re: Isopogon and Psoralea pinnata

Looking at the old seed heads on Isopogon formosus, I
can now see why the common Australian name as well. 
Interesting to hear other's travails with this plant,
it has been exceptionally floriferous for me, as well
as easy culture.  I have generally planted it in sandy
loam conditions with regular drip irrigation or micro
spray, and plant on raised mounds when dealing with
clay soils that drain poorly.  It has also done quite
well as a container plant with twice a day drip
irrigation for a couple of minutes and a coarse, fast
draining mix.  As a container plant, it becomes
conditioned to regular watering, and the plant will
defoliate along the stems if allowed to get too dry. 
It receives the same soil and watering as Psoralea
pinnata, also in a container, and both do well.  It
has done well under such conditions for the 3 years I
have grown it in containers.  I find that most of my
Proteas do well as container plants if I can keep the
roots relatively shaded, provide consistent light drip
irrigation and use a fast draining yet somewhat
moisture retentive soil mix.  It may also help that my
microclimate is cool and distinctly maritime
influenced, and we seldom get that hot or cold.

I have also seen 1 gallon plants blooming heavily when
only 18 inches tall, and they are such fast growers
here that a year later the same plant can be almost 4
feet tall.  Perhaps this plant is at its best in
California nearer the coast, and Tim's heavy blooming
is related to the generally mild winter with regularly
spaced rains we had this year.  I would have to agree
that many western Australian plants can be problematic
to keep growing here, and poor drainage and/or too
much watering had almost caused me to give up on
Kangaroo Paws, until I tried some more vigorous
selections of Anigozanthus flavidus hybrids in the
ground, with full sun, instead of as container plants,
where they were difficult to keep happy.

Regarding Psoralea pinnata, I suspect the lack of self
seeding here in California is  due to our drier
conditions, and that sunny moist seeps are not really
common in California, especially close to urban
gardens, this type of habitat is usually shaded from
trees or dense evergreen shrubs, and as the seed is
not bird spread or wind borne, is not invasive beyond
the immediate vicinity.  I only occasionally find
seedlings in my own garden.

There must be an immense variety of characteristics
for this plant in the wild.  As Glenn mentions about
the soporific qualities, I only notice the fragrance
if I go up and sniff the flowers, and the other older
clone of summer blooming plants of this are not
fragrant at all.  Podalyria calyptrata is another
legume with showy pinkish/mauve flowers for moist
sites, but I have never gotten this to survive in my
garden.  Even the few plants at Strybing Arboretum are
rather leggy and raggedy looking by comparison to the
magnificent examples I saw in the wild and at
Kirstenbosch.  This makes me suspect that the plant
has an associate soil borne companion that it needs to
grow well, and if the roots were innoculated, perhaps
it would thrive as well here.

As to growing conditions for Psoralea pinnata in
California, it seems to do well as a garden shrub
receiving just average summer watering, and in my clay
loam soils it can go several weeks without irrigation.
 It had never occured to me that this plant would
prefer it on the wet side, until I saw this was where
it always grew in the Capetown area.  It is hard to
keep this plant tidy and compact, it wants to become a
small tree with the lower branches dying out as it
gets large.  A small grove of them as an overstory to
groundcover of something to fill in at their base is a
good way to grow them, and you can see them at Alice
Keck Park in Santa Barbara grown this way.  Trying to
keep them sheared as a lower hedge is not the way to
grow it.





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