Re: how to plant Leucadendron

david feix wrote:
> 
> Hello Ellen,
> How much amending will be preferred will also depend
> on the rate of existing drainage, and whether there
> will be irrigation in summer or not.  
> 
> In my experience, many of the hybrid Leucadendrons
> sold here in California seem to be easier to grow than
> Leucospermums and Proteas, and not all that fussy
> about soil as long as they are given good drainage and
> not overwatered in summer.
> 
> --- emhoffs <emhoffs@ucla.edu> wrote:
> > My daughter is planting 20 Leucadendron.  She has
> > done extensive research
> > about how to plant them in her clay soil, however
> > everyone seems to have a
> > different answer.  Several people have told her to
> > increase drainage by
> > planting in decomposed granite (DG) and native soil;
> > others suggest that
> > she not amend; while some say to treat the plants
> > like any other and amend
> > with pumice and planting mix.  She was favoring the
> > DG method until she was
> > told that the DG would turn to cement in a year or
> > two.

Hi Ellen
This reply from David seems pretty definitive to me and he has the
advantage with his advice over anything I can give that he is conversant
with your local conditions. However I would just like to make a couple
of points and one tentative suggestion.

Proteaceae come almost exclusively from South Africa and Australia (all
Leucodendrons from the former), two ancient countries where the soils
have almost all ended up so deficient in phosphate that the Protea
family at least has tended to develop a lifestyle in which large
quantities of phosphate can act as a poison. Rule number 1 is therefore
never add any phophate fertilizer.

Almost all soils which the family grows on are poor, open  and free
draining and the root systems are very delicate and incapable of pushing
their way through heavy clay. One effect of this would be that in heavy
soil conditions they cannot spread far and the plants are very likely to
fall over as they get older and heavier. It also makes them very
sensitive to root rots.

Rule number 2 is therefore to keep them out of the clay as far as
possible and this is where David's mounds are likely to be the most
successful option among the many suggestions you have received. The lack
of soil depth will not bother them much, as they don't grow big root
systems anyway and in time the upper clay may anyhow become sufficiently
penetrable for some roots to venture into it. Stability could be assured
by putting heavy stones over the root zone, as they would often enjoy in
nature. One thing one should not do is to put them in a sheltered
position where they might have to cope with stagnant air. Most
Proteaceae really enjoy a breezy position.

The suggestion (very tentative) is that while any chemical amendments in
the soil are definitely a no-no, your daughter COULD try a light
top-dressing of straight compost. This was always consuidered a no-no by
South African growers, but many years ago when some visted New Zealand
they were amazed to see Proteas at least really flourishing (far better
than at home) with such treatment. It seems that, the presence of the
approprite living organisms in the compost prevents the phosphate being
released in quantites above the roots requirements while supplying other
nutrients, and possibly also  maybe providing appropriate mycorrhizal
partners for the roots, as one of your other correspondents suggested
are important..

As I say, this suggestion is entirely tentative and I would not
guarantee it will be successful - something to try on just one or two
plants to begin with perhaps.

Moira
-- 
Tony & Moira Ryan,
Wainuiomata, North Island, NZ.     Pictures of our garden at:-
http://mywebpages.comcast.net/cherie1/Garden/TonyandMoira/index.htm
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