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Re: Proteaceous plants in clay soils

Thanks for your response. I neglected to mention that the bed is already 
slightly raised (15cm) and I'm thinking I'll mound the soil within it's 
current curb. The bed's about 2 meters deep by 5 meters long, surrounded 
on three sides by pavement; the fourth side is against a building. 
These plants, now all in one gallon cans, will get to be seven sizeable 
shrubs. Do you see any problem with planting them in a bed of this size? 
It's always a bit breezy here, but we rarely get any real wind.
Wallace Gorell

> Your soil mix would be even better if you were to include some gravel.
> Most Proteaceae are fanatics for good drainage.
> 
>  From that point of view I don't at all like the sound of your bed. Just
> replacing your clay with  an area of suitable soil, especially if it is
> on the flat, would almost certainly create a water sump.
> 
> To have any chance of success you will probably need to make a raised
> bed. You could first improve the drainage over the area to some extent
> by digging in gypsum and clay or gravel and then put your bed on top,
> making it say 10" high and surrounding it with some sort of retaining
> wall such as rock, concrete blocks  bricks or  timber.
> 
>  Hopefully  some water will be able to  drain down into the opened up
> clay and the remainder will run out from the bottom of the wall. I don't
> think you need to worry about your plants having enough depth for their
> roots. These plants tend to have rather limited roots anyway which also
> means if your site is at all windy they will need staking until
> established. Even better is putting rocks round them to hold the roots
> down.
> 
> You are quite right not to give phosphorus, which is poison to these
> plants. Actually, you probably do not need to feed at all as they are
> more likely to have a long life if the soil is very lean. If you like
> you could give them just a little compost as a top dressing, but even
> this is probably unnnecessary. I have a Protea Cynaroides which has been
> growing in a nich in a rocky hillside for the last 35 years without any
> feeding. The bush is immense, looks in the pink of health and produces
> an average of fifty enormous flowers yearly. Although we can sometimes
> get pretty dry summers it has also not received any watering apart from
> its first three years.
> 
> Water as you suggest through early summer, as this will encourage good
> growth,  but you should stop for the late summer and the whole of
> autumn, however dry. This is a very dry period in their natural habitat
> when they become virtually dormant and if watered then you are quite
> likely to lose them. On the other hand most come from winter rainfall
> areas and are quite happy to be wet at that time (Strange, eh?).
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