When I had my native soil lab tested when we first bought the property, my phosphorus was four times the recommended minimum. When I questioned the lab results, I was told that my test was not unusual for California. This property was native woods until cleared 50 years ago. My growing experience with Australian natives has been similar to yours. Al

I am near Palo Alto.
This plant is 15 years old.
I bought it as a single twig at Yamagami's Nursery in Cupertino.
It was originally planted in a small octagonal wooden planter, so it was off the ground a little bit.
The planter is still there and is located down low on the left side of the picture where those thick branches are.
There is a mandarin orange tree near it that I fertilize and I assume citrus fertilizer contains phosporous. I do try to keep the fertilizer only near the mandarin.
Maybe I've been lucky, but this thing has thrived and then some.
I don't water it much in Summer.
I prune it to keep the pathway open.
It is a good six feet tall and maybe 8 feet linear. It is not extremely wide. It is beautiful and makes a nice screen. This picture was taken in November.
If you ever go to the Arboretum at UC Santa Cruz, there are lots of these and they are considerably larger as they are planted in open spaces. There are some impressive South African / Australian plants at that Arboretum. I bought a Banksia there and I have not killed that yet.
{{gwi:504081}}

Leucadendron salignum types are amongst the most California soils tolerant South Africa Proteaceae members to grow here, and are generally quite able to deal with most local clay soils if they are given good drainage and kept mulched and not fertilized except with alfalfa or cottonseed meal. They can also be prone to attack by Phytopthera if you water at the wrong times; warm wet soil exacerbates this and they can die quickly. In general they are safest to plant on slopes or raised mounds, and if the existing soils were once fertilized with regular fertilizer you may have toxicity issues with residual phosphorus. Drip irrigation during the cool of the night, and late fall planting to minimize need for frequent irrigation is the ideal. You might want to also get your soil tested if you suspect soil problems are the cause. Even straight nitrogen can kill them if applied too heavily, I generally never fertilize them in the ground, but if I do I use only alfalfa or cottonseed meal, in combination with soil sulpher to keep the soil ph closer to neutral.

Bahia - thx. As luck has it, my garden is as you suggest - all of the Leucadendron (and many others) are planted on mounds with good drainage and mulched. The garden is irrigated with drip in the wee hours. I never fertilize anything. Before I read the UC Bot garden post, I suspected overwatering as the reason for the death of the large 'Safari Sunset'. I had foot surgery last year and was on crutches for two weeks and could not easily get out and about in the garden. My husband cranked the watering to 120% of normal as it was a heat spell (in the 90's, unusual for here) and the first time that I went out I could see that the SS was 'off' and it was dead within a week. That could have been Phytopthera per your comment.

Now that I see Deeproots photo I realize that I saw a huge SS at the Gamble Garden in Palo Alto, so Bahia your comment that these are more tolerant than most of the other Proteaceae mitigates UC's blanket statement. I will make sure not to overwater or water during the heat of the day.

Thanks all - very helpful!

Sometimes they just like to drop dead for no apparent reason. I live in an area on the central coast with very sandy well drained soil and often you see a yard with several planted together and one dead in the middle of a bunch of perfectly healthy ones.

Thanks clematis...I think that bahia's comments may be the answer. If they are prone to Phytopthera when watered incorrectly, that would explain the 'dropping dead for no apparent reason'. I will try to be vigilant about watering properly.

And then, of course, they are frost tender, so I'm sure that once I get my watering to their liking, we'll have a hard freeze (which we virtually never do) and that will do them in. As Gilda Radnor said, 'It's always something...'

My Safari Sunset was planted on a bank above my access road, where it survived more than 5 years with no water at all. The native planting which grew up around it must have also competed for the soil water. The jungle got beyond what I could keep cut back, but I don't think this plant is still alive in there, and that was the last one of my Australian plants. Al

I'd love some advice from those who know leucadendron, even though I'm in the Pasadena area, not the Bay Area. About two years ago I put in two varieties of two plants each, Jester and Salignum Blush, on the side of my house, which gets strong southern exposure.

They were all doing well, but then over the last six months or so, one of the Salignum Blush seemed stunted and then browned at the edges. I thought it was drying out more than the others so I tried giving it extra water. But it's looking worse and worse.

I would appreciate any thoughts on what I could be doing wrong. I'm attaching photos of the two Salignum Blush, put in at the same time, about four feet away from each other. The one on the left is gorgeous, the other looks like its days are numbered. Thank you!

I doubt lack of water was your problem. Being in the ground for two years and doing well, in what is essentially a concrete cubical there should be plenty of moisture, maybe too much. I think you can't do anything now but watch it die, or recover. If you read this whole thread you can see many possible problems.
I have just finished clearing the bank containing my last Safari Sunset. It was hopelessly compromised by native growth. A combination of California Bay, poison oak, and blackberry. If properly maintained it may have survived, as it had a trunk of more than 4 inches, with a large amount of foliage, cascading down the bank to the north. Al

I can't add any more than I've noted already...I am now treating these plants as short-lived, like lavender and such, and consider them accents in the garden (which is how they function anyway, given their dramatic coloring). So now I'm sure they'll survive to spite me, and outgrow their locations!
Sara

Just to add my own experience: I am also in the SF Bay Area, and over the last few months (summer/early fall) two of my leucadendrons went from vibrant to dead in the course of a few days. One was a leucadendron Safari Goldstrike. We had a heat spell in the middle of the summer, and I noticed one afternoon during that heat spell that the plant was suddenly looking noticeably wilted, so I doused it with a good amount of water in the middle of the afternoon. Over the next few days it went from wilted to totally dead. The other sudden death was a leucadendron Jester. Again, it died the week after a late summer heat spell. I didn't water it during the middle of the day like I had with the Safari Goldstrike, but I did turn the drip watering up to 120% that week. When a plant pro looked at the Jester after it died, she noted it had black spots on its leaves, suggesting some type of mold/mildew infection.

Meanwhile, in another part of the yard, due to an irrigation problem that we didn't find out about until just a few weeks ago, a leucadendron Safari Sunset continues to thrive despite receiving NO irrigation for all of August and September.

In summary I think it is highly likely that what killed my two leucadendrons this summer was indeed Phytopthera exacerbated by heat/excessive watering. Hope this can serve as a cautionary tale for others in the future.