Fish emulsion/fertilizer

@gardengal48 (PNW Z8/9) What about combining fish emulsion or blood meal with kelp meal for the potassium?

Why?

Rather than a one-word answer....You did say these were in the same family, not necessarily specifically within the Protea genus, so the exact requirements might vary from the sugarbush and you might have a lot more wiggle room than if this were actually a Protea.

So of course even if the requirements are the same, you may if the soil's very low in potassium. But please note, Protea don't require much potassium and it's potentially problematic, particularly when combined with phosphorus.

So it's probably wise to have a soil test in-hand showing low potassium and low phosphorus before doing so.

If requirements differ, we'd have to know the genus and species to be more specific. Grevilleas (Proteacae, but not Protea), for example, do enjoy some potassium, but overdoing it wouldn't be a great idea.

Well, that's interesting, to say the least, save that it doesn't necessarily apply. In a container, one wouldn't expect a soil, but a potting mix, one presumes, so I wouldn't quote that here.

" Refraining from fertilizing is a good bet." So the fish emulsion recommendation isn't necessarily great to begin with. Nor would I necessarily call 5-1-1 no phosphorus and low potassium compared to its N when that's not terribly far off the "normal" 4-1-2 ratio.

I might consider blood meal very sparingly (12-0-0) a better recommendation here if one were to really want low P and K instead rather than following a set printed recommendation without actually considering the chemistry or having said soil test; a Protea (although again, one is failing to consider the statement that this is not a protea just in the same family, just as a Zinnia is not a Daisy but is in that family) is specialty enough to warrant it.

The quote's disingenuous to the point of being wrong here just due to not applying to the correct genus.

@westes Zone 9b California SF Bay, we're at a sticking point. Is the plant a Protea, in the same genus, or in the family but not in the genus? Feeding varies a bit if not, as noted, and the quoted article does not necessarily apply. Similarly, you're using a container mix, not native soil, yes (soil in a container's usually not such a great idea, although....)

@User An ideal container soil for Protea is 2 parts sand, 2 parts peat, and 1 part 1/4 inch rock / pumice. That's a formula I got from a professional Australian Protea grower. I don't have the plant in any soil yet. I am just planning out whether I want to deal with a plant in this family that has the extreme phosphorus sensitivity.

The plant I am interested in is Adenanthos sericeus aka Australian Woolly Bush. It is in the Proteaceae family, and reading about it suggests it has the same phosphorus sensitivity that Protea genus has.

https://aussiegreenthumb.com/adenanthos-sericeus/

https://www.gardenersdelight.ca/2024/04/growing-guide-adenanthos-sericeus.html

My prior attempt at growing King Protea ended up with my gardener killing the plant after one application of normal fertilizer.

@gardengal48 (PNW Z8/9) I guess your comment is for the other poster. I accepted your suggestion of fish emulsion and not using fertilizer at all unless the plant clearly signals that it needs it.

" I am just planning out whether I want to deal with a plant in this family that has the extreme phosphorus sensitivity. "

Maybe. Definitely in a container, your local soil has no general reliable reports except "definitely not phosphorus deficient," which is what the plant evolved in. In this case, the container would also have to be isolated from your local soil, so not placed atop it where the plant roots could then penetrate into your soil (and thus tap phosphorus and damage or kill the plant). On a patio, on a stand, whatever.

" Adenanthos sericeus aka Australian Woolly Bush. It is in the Proteaceae family, and reading about it suggests it has the same phosphorus sensitivity that Protea genus has. "

Ayup. Looking specifically for that genus and species, it does, but the feeding is a tad different and resources suggest that an organic is fine--with a very light hand. Not feeding, or feeding very lightly with pure nitrogen (slow release) is also fine. Again, never follow the guide for the genus/species of a plant that isn't yours, it's not quite the same.

In this case, as noted, organics are allowable. I'd probably just use slow-release urea with a very, very gentle hand and always let the plant be my guide (there are no exceptions to that rule).

" My prior attempt at growing King Protea ended up with my gardener killing the plant after one application of normal fertilizer. "

It turns out two of us were watering the large Desert Roses this year over winter. Two did not have to be transported out into the gardens, at least, and I got the pots back for something else...

It's always sad when that happens.

well that was weird and a dark mystery to me.