sounds intriging
I hope that you will keep us GWebbers posted on your little experiment
even if it isnt true science it will help us all under these plants

keep us posted artie

I will be looking forward to hearing how all this goes. I have two Grevillea banksii very close by to frangipani and hibiscus so surely these two would get some of the fertlizer I add to the others, the hibiscus I feed once a month.

You know I never though about it till I read that thread, tell me if what kind of fertlizer would I need to use near a G.robusta to help with its demise as Organic Extra is certainly not working. Brand name if possible Thanks Artie. Cheers....MM.

Good luck Artie. Keep us informed.

Like you say, it's probably a good idea to wait before applying anything. With Osmocote NPK 16:*4.4*:10 on its own, I think the high nitrogen would actually promote growth, so yes, it will be interesting to see what happens.

I'd be leaning towards Ned Kelly coming through it O.K.

Thanks for the support, team.

MM, I think we both know that little things like fertiliser, bushfires and environmental degradation wont put a silky oak out of *your* misery :)

I often have to restrain myself when I see Robusta on sale at church fetes etc - it should come with a large warning for people on suburban blocks, IMO - great in the right setting, but just too big for the average block.

Well any ideas Artie to what I can give them to help them along to that beautiful place for trees in the sky..MM

Misty - I maybe able to offer you a solution, but you need some handyman skills for this task.

Into the trunk of the tree you need to drill a hole 1/2" diameter using a fairly long bit or drill. (Brace & bit is ideal) This hole can be fairly low to the ground but must be deep enough to reach the centre of the trunk or further.

From your hardware store purchase 30cm length of 1/2" copper pipe and insert this into the hole in the trunk. Then wait - as the copper will kill the tree.

Never put a nail into a tree that may have to have a chainsaw cut into it to get it down.

Oh that is so interesting, no problem with the tools we built this house so somewhere there is a 40cm auger that hubby used to bore holes through the bearers, we have even got the copper pipe. But I am looking for a solution where I can do it from here like hummm through the soil

You are right robert we have a steering wheel column through one of our gum trees put there about 25 yrs ago when the big boys from next door were little, there was a star picket growing through another, and we have also found other odd bits of metal inbedded into the tree trunks on our block so hubby and I have had to look very carefully before he cut down the 23 trees from here..Thanks for the advice ........Cheers..MM.

It's a great idea to experiment by comparing like plants under different fertiliser regimes. An addition to the experiment might be interesting ... Since Grevilleas of the Robyn Gordon / Ned Kelly type (presumably including Coconut Ice) are said to be particularly susceptible to phosphate poisoning, it could be instructive to plant some that are said to tolerate it relatively well, and subject them to the same comparitive regimes? These would appear to be Grevillea olivaceae and its descendants. IÂm not sure whether these include "Apricot Glow". Do any members have experience with these grevilleas?
Trish

Trish,

I have Grevillea olivaceae and it's growing very successfully. I've had to prune it a few times, otherwise it would have taken over! No problem with yellowing leaves, but I have another little groundcover grevillea very close by and it's miserable - growing poorly and yellowing.

As I've said in another posting, the hybrids with G. banksii parentage are also very successful with no yellowing.

Rainforest proteaceae such as North Qld Tree Waratah was a little prone to yellowing when small but now has no problem.

Cheers,
Frank

How are the grevillea's looking Artie. I'd half expect you to say they are doing well with no side effects.

Can you give us an update on their health - thus far.

So far so good - they had to cope with a deluge recently (very rare in Rocky - but are doing well. I am going to up the ante tomorrow, but I have to admit that my initial resolve is faltering in the face of such healthy, cheerful little plants. Interestingly, one of the lillypillies near them keeled over and died, but I think that had more to do with sunstroke than fertliser.

Osmocote plus NPK 16:*4.4*:10 would knock over quite a few plants when young.

I'm still tipping the G. Ned Kelly to be the winner and actually show no effects at all.

I am pretty much a novice when it comes to Australian Natives - have up to now grown almost only exotics. But now have the space to grow a variety of plants. Because of heavy rocky clay, I am growing almost everything in raised beds and have brought in much of the soil which is a problem in its own right. However I have planted a rainforest garden with reasonable success. Using the same soil I created other beds and planted a variety of grevilleas. To date I have lost every one including Ned Kelly, Cantebury Gold, Flora Mason, Robyn Gordon & Scarlet Sprite. Austromyrtus and Melaleucas have been fine. I finally paid for a soil analysis, as the supplier was not much help. And there were no surprises - the levels of Phosphorus in the soil were toxic - 227.4 ppm as opposed to the desired 50 ppm. Sulphur, copper, zinc and manganese were also well above desirable levels. I haven't given up on Grevilleas - will just take another approach.

Hi there,
I feel for you, Artie. It goes against-the-grain for a gardener to poison their plants. But it's all in the name of science! They will be martyrs...

Update?
~Onion

Hi Onion,

Living in Northern California, you may not know that much of Queensland has recently been deluged (a cyclone and a couple of other low-pressure systems). I did apply another round of Osmocote shortly before the 'flood', but I believe that this was washed straight past the roots within days (hours ?) of application.

As I mentioned in my initial post, my aim was always to see what happened to the Grevilleas *without* harming the other plantings, so its probably back to the same dosage as the last batch in about a week or two. It would give me little satisfaction to have a Grevillea survive and one of my prize Syzygium Cascades keel over, as unlikely as that seems ...

Cheers,

Artie

Thank you for the update, Artie. I had not heard of the cyclone. I hope your plants are okay.

Here in northern California we've had a month and a half of unusually rainy weather, too. I've resorted to putting an umbrella over my rain-intollerant trough plants!

Best wishes,
~Onion

My young banksias in snuffy toowoomba redsoil suffer from yellowing of the new leaves, but I seem to be able to fix this by sprinkling iron chelate. The results are dramatic. Apparently Toowomba's soil can have a problem with not enough available iron, despite its lovely rich red colour.
I think Frank has the same kind of soil? Perhaps a lack of iron, rather than any phosphorus problem might be the cause of unthriftiness in some grevilleas in some areas?
Any comments about pH for grevilleas/ (I notice the writer from California, who asked for advice on growing "Proteas" got given advice in both directions!
Trish

Trish,

I do have the same problem with yellowing of proteaceae. Have a look at the pdf file linked below. The last sentence of the first paragraph and first sentence of the second paragraph under 'Interpreting Soil Data' explains what I understand the situation to be in Toowoomba and the Downs. The iron is there in the soil, but alkaline soils make that iron less available to the plant. Using iron chelates is a quick fix but when I tried that, it was necessary to continually reapply it because the alkalinity just overpowered the chelates before long. That gets expensive. Others have used sulphur and iron sulphate to try to adjust the pH and therefore improve iron availability, but that takes longer to be effective.

It occurred to me recently that maybe I should just try adding some vinegar to any water I use on the sensitive plants (not any lately). The town water is quite alkaline and worsens the problem. Adding some vinegar should in theory overcome this I would think. I have been meaning to follow this up by checking how much vinegar to add with some pH indicator test - I'm thinking the kit that gets used for checking swimming pool pH. Vinegar is cheap and I can't imagine much would be needed.

Cheers,
Frank

Here is a link that might be useful: basalt soil alkalinity

Adding lots of humus to the soil will decrease (acidify) the pH. If you have really alkaline soils maybe you should grow lots of veggies as a green manure then dig them in/cover them over.

I'm still waiting for the results of this test. None of my test grevilleas have suffered from similar applications of no-name brand high P fertilizer. Indeed they are looking better and better.

Eremophilas also seem to enjoy more P.

Hi Nathan

I will be applying the Osmocote very soon, as I am also anxious to see how it goes. I'm a little frustrated with this particular bed, as the lillipillies and Pandorea vines dont seem to be performing as well as they have in other parts of the garden. Sloping beds have superb drainage, but I believe that also leaches a lot of the nutrients from the soil.

My bed at the front was also annoying me with its propensity for killing young Grevilleas planted in a certain spot at the rear, so I replaced the last victim with a dwarf Melaleuca about 6 weeks ago. The little fellow looks so happy that I am tempted to plant them in all future garden troublespots - at $2.50 ea from the local markets, its hard to go wrong :)

Cheers,

Artie

As I have tried to make clear previously, I don't dispute that high P levels are relatively more toxic to Proteaceae than to other plant families, but I do believe that many rainforest grevilleas are less susceptible than WA species. Again its a relative thing, and I have certainly found one that isn't. A landscape supplier dumped a truckload of potting mix in my garden, close to some trees but about 6 metres from a G. baileyana. Some months afterwards it died, and on digging up the mix it was full of proteoid roots! Retrospectively, I have realised I have had a much higher proteaceae failure rate since using that mix, so I must find out what's in it. The seller told me it was fine for natives - you'd think that at my age I'd know better than to trust a salesperson, but my problem is I can remember back when most of them were trustworthy.
Tony

Hi All,

Just wanted to record that the Osmocote was applied a week ago and I havent seen any sign of distress on the part of the grevilleas as yet. Some of the nearby Gardenia Radicans are looking a little yellow, but I suspect that may be a nitrogen issue - they havent had a whole lot of TLC in the last 10 or so months. When I come to think of it, that bed has really been a tough place for every plant in it. The lillipillies (Syzygium Cascade) and the large-leafed Ixora have powered, but the rest of it seems to be just hanging in there. Darwin would have been proud of the Rocky sun's ability to select the 'fittest' ....

Cheers,

Artie

Of course plants dying is not proof that P killed them. Proteacea are often suceptible to root rot, (esp Phytophthora cinnamomi). Perhaps that load of soil had some root rot in it. High Phosphoric acid has been shown to control Phytophthora, so yet another idea is that the soil was contaminated with Phytophthora and the high P levels controlled it until the plant sucked all the P up, at which point the water mould invaded.

(yes, I'm making this up as I go along, but I think the general point is valid)

Hi Nathan,

It is my sincere hope that the drainage in my Grevillea beds is sufficiently good that I wont lose anything to root rot, but its posts like yours that make me wish I had used crushed sandstone instead of simply mixing sand into the existing soil. Don Burke's book always comes back to haunt me when I look over at that front bed.

Cheers,

Artie

Limestone is good too, apparently.

Team,

The two lab rats ('Coconut Ice' and 'Ned Kelly') are going strong a month after the Osmocote application. I cant say whether they are still actively growing at the moment (daytime temps still in the mid-20s), but there is no sign of yellowing at the tips etc. despite a couple of downpours since the fertiliser application. This doesnt *prove* that these tropical grevilleas can handle high Phosphorus loadings over time (it may have been leached away by the rain), but it is encouraging nonetheless. Will repeat the dose in early Spring and report back.

Cheers,

Artie

Very interesting Artie - I think your high Phosphorus Osmocote is also high in Nitrogen and I believe the (N) will "overpower" the (P) in some circumstances, encouraging growth.

I tipped that Ned Kelly would take all you give and still come out loving it. I may be right!

I dont know enough chemistry to comment, but surely thats a *good* thing, JC ? It would mean that I could apply Osmocote the lillipillies, exotics and Grevillea with equal abandon :)

Artie - I wouldn't just apply this fertiliser to everything until you see how the plants react to it. High Nitrogen will help in the developement of the new foliage. I use a two in one fertiliser here which is IBDU & Permacote, but the Nitrogen level (30+)in this is over twice what you're using and noticeable foliage growth can be seen.
This fertiliser works for me, in my climate and on my plants - it may have adverse effects in a tropical situation for you.
Err on the side of caution if you're unsure.