If now is the end of the growing season for you there in Victoria, Australia, and the amount of black spot is showing primarily on the oldest foliage of the Icebergs, it may be acceptable, and otherwise, the bushes performed rather well all growing season long until just recently. Black spot appears suddenly and progresses quickly. Black spot that attacks earlier in the growing season (Which may be your case, but I think not.), and defoliates the bushes very aggressively and quickly, so that by now, almost no foliage is left on the bush is a very serious condition. This does not appear to be the case going by the amount of blooms seen in your photo. Plus, a yearly ravaging of aggressive black spot would eventually kill a rose. Your bushes seem not to have endured such a situation.

If now is the end of the growing season for you there in Victoria, Australia, and the amount of black spot is showing primarily on the oldest foliage of the Icebergs, it may be acceptable, and otherwise, the bushes performed rather well all growing season long. Black spot that attacks earlier in the growing season and defoliates the bushes very aggressively and quickly, so that by now, almost no foliage is left on the bush is a very serious condition.

This does not appear to be the case going by the amount of blooms seen in your photo. Plus, a yearly ravaging of aggressive black spot would eventually kill a rose. Your bushes seem not to have endured such a situation. in your photo. Plus, a yearly ravaging of aggressive black spot going unaddressed (not sprayed for routinely), would weaken and eventually kill a rose bush. Your bushes seem not to have endured such a situation.

I suspect your roses, if black spot pressure there is intense, were regularly sprayed with a fungicide, and that routine was discontinued recently hence the emergence of black spot now.

Why not check with the previous owners, or neighbors who have knowledge of the care your Icebergs got, and if they grow roses, they can share their care routine given for your immediate area.

If roses do not truly go dormant over your winter and growth just slows down, you can prune in late winter/very early spring. Your bushes should be pruned every year.

If you now live near the coast, like in the vicinity of Melbourne, black spot issues with growing roses may be a way of life because of the heat and humidity.

Moses.

*note...My computer is not compatable with the Houzz system and frequently goes haywire with repeated sentences and phrases which are nearly impossible to correct. This makes reading my posts nearly as difficult as it does for me to compose them! Please bear with me.

Surely someone other than me can advise Alice on her black spot issue? I would think, an Aussie would have come forward with advice by now, not only a lone American so far, who gardens half way across the world. There's no language barrier, folks!

Moses.

Thanks, Trish. You're a good egg! Thanks for doing a solid for Alice!

Moses.

Thank you Moses and Trish! I'm grateful for your responses. It turns out the previous owner has never sprayed her roses, however like Moses said, it is the beginning of winter and the roses have done exceptionally well so far. The previous owner was not worried by the blackspot being the end of their season, and has advised to wait a month or so before pruning, and then to clean up all the diseased leaves.

Alice,

That's good news! So Iceberg growing under your specific growing conditions is able to endure black spot pressure, and bloom satisfactorily. Iceberg is a nice old floribunda, with great fragrance and equally so flower production and repetition output.

One thing you may want to determine from the previous owner was their care beyond late winter/spring pruning and diseased foliage cleanup. These three points seem minimally to need to be determined: 1. what was their fertilizing program, 2. were they regularly dead headed, 3. how about weeding, watering, and mulching?

The more information you get, the easier and better the care program they will get, and you will be happier for it.

In due time, you may consider replacing the poorly growing Iceberg bushes, and also to break up the monotony, with different varieties than fresh Icebergs, especially newer varieties of disease free/resistance for black spot ones, and those in different bloom colors, of which there are a multitude of selections in commerce. Rose breeders of the current generation have progressed light years ahead of the breeders of Iceberg's era roses, with a multitude of desirable traits, especially disease resistance qualities that are far superior to roses from Iceberg's generation.

I wish you much joy and success in your new home.

Moses.