My prejudice is that not that many roses bred on the West Coast that would survive in England. Not without some extra work. One of the observations I made while growing roses in NJ was that most roses bred in Germany and England were more resistant to black spot than roses bred in California. So I formed the impression that English and German rose breeders put more energy into breeding cultivars resistant to fungal disease than Californian rose breeders. That's possibly something that has changed a bit in the last decade or two. I think many of Carruth's introductions, for example, address disease issues.

One of the great motivations of David Austin's breeding program was to develop a line of roses that survived happily in the British weather without much spraying - a fact that suggests to me that disease among hybrid teas and floribundas bred for the British Isles before his work was considered to be a significant problem when he started in the sixties and seventies.

The coolness of English summers, I think, can explain why they might not have to worry nearly so much about blackspot as, say, rose growers in Arkansas. But that same coolness promotes powdery mildew just as it does along the coast of CA.

It seems to me that roses with a stronger dose of multiflora heritage might be a little more prone to mildew, on average, than those that have less. And roses with dull leaf surfaces seem to suffer from mildew a little more, on average, than those with shiny leaf surfaces. FWIW. In any case, I would expect most David Austin roses to fare pretty well in coastal CA. Even at the height of my mildew outbreak, I have not observed any mildew on any of my DA roses here; but I do not have Pat Austin.

Finally, I notice that in the case of powdery mildew, it seems to be the new fresh leaves that get attacked first. The old established leaves seem to be a little more resistant. I guess this is one of the reasons people suggest that overfeeding roses can promote mildew.

Roses really don't grow well on the California coast, at least the coastal locations I know well. When I lived in San Francisco, for example, I didn't know anyone who bothered to grow roses when other plants were so much more gratifying to grow. Most San Francisco gardeners concentrate on azaleas, rhododendrons, fuchsias, pelargoniums, and various bulbs.

I think the reason roses grow so well in the inland Calfornia regions like mine is that our nights are always comparatively cold. Even when the temperature soars into the 90s or into triple-digit territory, the nighttime temperatures dip down into the 40s and 50s.

This (hot days and cool nights) is often alleged to be a recipe for powdery mildew, but I have never seen powdery mildew on any roses other than OGR's in my garden. I have to assume that modern roses are resistant to it here. There is something else, though. I believe in overhead watering. It cleans the leaves, knocks off the aphids, and retards powdery mildew because the powdery variety of mildew can't grow on a wet surface. The roses in my garden that suffered from powdery mildew were huge ramblers that I couldn't possibly have watered from overhead without a helicopter. Dorothy Perkins was the worst, and I've replaced almost all of mine with Super Dorothy, which never gets powdery mildew.

David Austin actually produced a few roses that were never sold in England because they were more suited to the Northern California climate. The Endeavour is one of them.

My understanding and my (one) experience with powdery mildew is that when the temperature soars above 90F during the day for a few days in a row powdery mildew is just about finished off. Large temperature swings like those you mention will bring humidity pretty low for most of the day, again dealing powdery mildew a pretty strong setback. So in inland CA daytime temps are too warm for powdery mildew and nights are too cool for blackspot. Finally the relative humidity for most hours of the day through most of the growing season is just too low for any of the fungal infections to thrive. It's just about as good as it gets for growing roses.

It sounds like Austin realized that he could sell roses not fit for England or any part of the US east of the Rockies into a market that already embraced quite a lot of such roses.

Again, it seems to me that roses bred and sold where climatic conditions are similar to those of coastal California might offer more resistance to powdery mildew than roses bred in and for the inland California market. In addition to roses offered by David Austin I'd check out roses from Palatine. Heirloom Roses has a whole line of roses bred by Harkness that might be promising. I'm tempted to suggest roses offered by ARE, but they tend to be targeted at resisting black spot more than mildew. Mme Alfred Carriere, for example, seems to be my most vulnerable rose right now and it's from ARE: I'm hoping it performs better once established.

Zuzu, My limited experience with powdery mildew suggests that the roses most vulnerable are the ones growing the fastest. The mildew sets in principally on new foliage. Very little established foliage has been touched by it. So I wonder, if one waters a little more lightly and fertilizes a little less - especially with established roses - does this provide a measure of protection to roses against mildew? It seems to me that there might be a spot of evidence to support this. In his book on climbing roses Quest Ritson claims that Mme Alfred Carriere was panned as a terrible rose in England in the years following its introduction (though he doesn't say why), but forty years later it was by far England's favorite white climbing rose. Established roses would spend less time making new foliage, perhaps, and so would have less difficulty with the disease.

I have never had powdery mildew. Is it my hot humid climate or my negligent care practices? Here black spot seems to be most rampant in the cooler spring than the consistently hot summer...(?) During last summer's exceptional heat and drought, there was almost no black spot - even Iceberg and Europeana had leaves!

I guess Texas never gets cool enough at night for powdery mildew to become a problem on roses. It felt like that when I lived there, especially the year without air conditioning.

It's an interesting point about blackspot. My understanding was that it did not set in unless the temperature was pretty close to 90F. Much below about 80F, I don't think it strikes at all. My recollection of Texas weather is that springs tend to be damp in comparison to summers. In Austin, where I lived, the RH hovered around 50% through the daytime for most of the summer. And rain was pretty scarce. Of course, if humidity rises far from 50%, things can be very different. Not sure what the threshold is, though. I guess black spot has a high temperature limit - a temperature that kills it dead or at least keeps it from spreading. Perhaps that is near 100F.

In NJ I had downy mildew in the spring when the weather was cool and damp. It cleared up over the summer. So I think it's more a cool season fungus. I confused black spot an downy mildew with each other and am still not sure I could always tell them apart.

All three fungal diseases need high humidity. Not sure what that means, exactly; but certainly if the RH remains below 50% through day and night that's plenty dry enough. The common factor is humidity, but the three fungal diseases I've dealt with strike under different temperature conditions. Downy mildew is really a problem in cool, damp weather. In NJ April showers brought... downy mildew in early spring. It was generally gone - or at least it had stopped spreading by mid May. Powdery mildew is a problem in slightly warmer weather so long as the high temperature does not exceed 90F for long. It seems to strike more where there are larger temperature swings between day and night. Finally, black spot becomes the king of rose maladies when the temperature at night does not dip below, say 80F. In NJ that was all summer long. Interestingly, I don't remember having any problems with disease when I grew roses in Austin. Perhaps it was just dry enough. Or perhaps it was beginner's luck.

Another factor that influences which fungal disease prevails is the amount of residual spores. My guess is that the amount of residual spores just sitting there waiting to infect roses given the right conditions depends on how frequently favorable conditions prevail. Since it always dips below 80F at night here, and since for 10 months of the year the RH is never above 40%, my guess is that there's not many black spot spores floating around here. By contrast, every year in my garden I see powdery mildew on clover during the monsoon. Last year it struck some crowded dahlias but not the roses. So in my garden here powdery mildew is just sitting there waiting for rose vulnerability and the right conditions.

Interesting observations.. If downy mildew looks like black spot perhaps I have it here too.

92degs & 11% humidity.

Nope, no humidity.

Yesterday I sold my Cecile Brunner rose. I didn't want it as I had bought it as Lady Banks and I didn't want pink blooms, I wanted yellow. When I was digging it out for the lady who bought it, I noticed that I had about 4-5 leaves on Betty Boop that had yellowed & had blackspot on it.

Other than that, no black spot. I *think* I had powdery mildew earlier this year, but I haven't seen it in months & months. Looked like a white powdery film on the leaves that was easy to wipe off.

Now I gotta take a shower & take care of a massive blister on the ball of my right hand. It hurts.

Humidity can be a highly variable local phenomenon in a well tended garden. If Cecile Brunner had lots of foliage that shaded and enshrouded Betty Boop restricting light and air circulation, and if the area was kept well watered and mulched, it is not impossible that the humidity level near the soil where BB lived was considerably higher than 11%. But I do have to wonder where the spores come from. Maybe from pine bark mulch imported from Alabama's paper pulp forests? I'll have to take that into consideration as I water and mulch my garden.

Maybe I need to think of fewer roses and more gravel mulch? Perhaps I just need to prune more carefully and to plant more dianthus and iris.

Well, the Cecile had a lot of foliage, but that area wasn't mulched very well, maybe 1-2". I buy cedar mulch as I hate the bark mulch. And my poor dianthus is still trying to bloom..

Two inches of mulch is about 2" more than most of my garden has had for the last four years. Cedar's a good idea. That's probably what I should be getting. But I left the choice of material up to the gardening helper who will be putting it down ... so I don't really know what kind it will be. All I know is that there's going to be six yards of it in the garden soon. I guess we'll see what happens after Wednesday. Does mulch contribute to fungal disease? Stay tuned.

I don't know about fungal diseases, but I stopped using wood mulch years ago after I noticed that it was always full of earwigs and sowbugs. They're not bad for roses, but they wreck Clematis vines, which are planted in every rose bed in my garden.

When it was delivered, I got the analysis of Wilby's mulch - along with a photo of it's upstream supplier, Wilby the horse. The bulk of it is material cleaned from horse stalls: straw and horse manure. It's balanced with sawdust and/or wood shavings to give a favorable C:N ratio. Then it's turned and seasoned for about three years. It looks and smells like good stuff. I feel very fortunate to have found it. I realize that it will disintegrate quickly, and I'm hoping that in doing so it will materially enrich the soil. I expect to use this mulch until most of my roses are well established. I guess that means two or three more years.

Until I read Zuzu's entry about her problems with wood mulch, I'd imagined that I'd use cedar or some other wood mulch once I thought the soil had been enriched enough and my roses were well established. Now I'm not certain what to use next. I guess I could just keep on feeding the soil, but for some reason this seems like it will require more mulch than would otherwise be required.

I just deal with the centipedes, earwigs (gross!!), & rolypollies. And the cedar mulch has lasted much longer than the other "hardwood" mulch I've tried. And the soil is just completely chock-full of worms!! Love that!!

I''ll bet that explains why the birds are always digging around in my mulch. I stopped using Sevin to kill the pillbugs since I have beehives, and now I have many more birds, lizards and skinks. (NOT skunks, skinks.)
I could get away with just using ground cover plants instead of mulch if it weren't for the cold wind in the winter. Until i get some more hedgerows up to a decent size, I will have to protect, and wood mulch is definitely the cheapest option.
The compost I use is exactly like Steves--and since it is aged and turned for 3 years, there is no smell and no weed seeds to speak of.
It's $300 for a 15-ton dump truck load, so I dole it out pretty carefully. The horse farm is 1/4 mile away, and the compost guy is 1 mile away, but I have to pay the same delivery fee as someone clear across town.
At least my wood mulch is free, and I don't have to haul any of it in the car!

We make our own Wilby- type mulch here, but it doesn't get aged, balanced, or turned as well. The roses don't seem to mind too much.

I'm in the same camp as Zuzu when it comes to wood mulches and the earwig issue.
In addition, I quit using redwood mulch after one application because it just attracted termites. Contrary to popular belief, termites DO eat redwood and cedar...here, anyway.

When "going green" became the rage and cities here started offering free "compost", I went and got some...like a full truck load. Big mistake. It was horrible stuff...full of glass, wire, batteries, etc.
I didn't know that until I got it home.

Not to mention roofing nails, pieces of garden hose, plastic bags, and large chunks of redwood deck furniture! I got some of that stuff too, but I was stupid enough to pay a hefty fee for delivery. Almost all of it went into the garbage, recycling, and yard waste cans weekly and filled them up for the next month or so.

Redwood mulch is the very worst stuff because it also doesn't enrich the soil in any way. I do like to use the twice-ground redwood bark on my pathways, however. The last load of stuff I got for my driveways was plain wood chip and it's painful to walk on. The twice-ground bark is nice and soft and smells like a redwood forest for the first few weeks.

Zu: Didn't Don give a rather lengthy and informative spiel once about not using redwood as a mulch OR a soil ammendment when planting roses ? Something about the tannins in it being not so beneficial for roses. (Maybe it was someone else...)

You're so right about all the junk in that city-made compost/mulch. Seems like regardless of the city it's always full of debris of some kind.

Anyone use pine needles as a mulch ?

Pine needles would be nice, I'm sure.

I don't remember that particular spiel, but Don was always delivering spiels.

Mango Mulch seems to be the favorite up here. It's a local product, but it's carried by retailers outside our county. Here's what the manufacturer says about it:

"It doesn’t have any mangos in it, but it does have horse and cow manure to supply basic nutrients; grape and apple pomace which are high in beneficial bacteria and yeasts to aid with the breakdown of organic matter; rice hulls and straw for good soil tilth; soft rock phosphate and greensand to boost the phosphorous and potassium. We blend and compost these ingredients in an aerobic process."

It's only $49 a yard from Grab 'n' Grow, the manufacturer, so I think I'll order a yard or two.

No one has mentioned Alfalfa Tea in a while.
Is it passe now ?