If you don't do anything, the problem will get worse.

If you cut the canes with galls off, the problem won't be as bad next year unless you've a neighbor who has the same problem and is neglecting to do anything about them.

Not all roses are equally susceptible.. In my garden the species R. eglanteria got them really bad. Other roses didn't.

If rugosas grow well for you, if you love their fragrances and they are really great in your environment, I'd guess you want to keep growing them, even if you have to de-gall them once a year.

I have never heard of these before! I had to google them to see what they looked like. Egads! I'm glad I've never seen them here but I don't have any rugosas. Is that what they are most common on?

It's a toughie. I like the color, the winter hardiness and the fragrance. On the other hand, the fragrance is so strong, they are rose chafer & beetle magnets. I was going to cut off all the blooms this year at the 1st sign of the rose chafer and beetle onslaught in hopes of deterring them. Now, in addition to the those pests, they have the mossy rose galls.

Between the above mentioned pests, the aphids, spider mites, black spot, probable RRD on my Reine des Violette, and all the winter protection, it makes a girl wonder if it's all worth it.

Wow! Sounds kind of depressing huh? I think I need Spring.

Yeah, nothing like some sumptious blooms to remind us of why this is all worth it!!! I started getting depressed about my new rust problem, but when I step back and look at my garden which is starting its first flush of the season - all the garden problems (my personal ones too) melt away...

Seil,
I had the same question, so I went to the U of M extention site. This is what it said,

" mossy rose galls caused by Diplolepis spinosa were seen only on Hybrid Rugosa cultivars and Species Roses."

Harmony,
I'm sorry to hear about your rust problem. That seems to be one of the few problems I don't have, or maybe I just don't know what to look for yet. Maybe your right. When it finally warms up here for good, and I have something blooming besides phlox and my one lonely daffodil, I'll feel better.
Thanks,
Kitty

Thank you, Kitty! I'm relieved.

Harmony, yes blooms!!!! I can't wait!

I usually have a few mossy rose galls on my Rosa glauca every year. They're caused by a small wasp and never seem to do real harm to the rose itself. The canes never wilt or die back beyond the gall. I could cut the galls out, but I choose to accept them as part of the garden and let them go about their business. I guess it helps that I don't have dozens of them, nor do I find the appearance disgusting, but rather interesting. I kind of like a common name for these: "robin's pincushions."

Now the raspberry cane borers that cause the lumps on my rugosa canes I find much more destructive. The canes always die beyond the site of the insect's invasion which is very frustrating. I always seem to be pruning out more canes on say, Therese Bugnet than the plant puts out new each year. My rugosas have very few canes older than one year. Now THAT'S a discouraging pest, IMO, much more distressing than the mossy rose galls.

Here is a link that might be useful: More about galls in roses

Annececilia,
My mossy rose galls look nothing like the "Lorax tree" type galls I saw when I looked up "robin's pincushions". I will attempt to post a pic. of mine later.

Ann is right, "If you don't do anything, the problem will get worse."

I have to admit that I saw a couple last year, didn't know what they were, and being busy, I ignored them. This year they are completely covering one of my rugosas. I believe they ARE harmful to the host plant. Here is a quote from the University of Minn. Extension:

"The development of these galls is stimulated in the spring by newly hatched larvae. The galls encase the larvae until adult wasps emerge the following spring. The galls are unsightly and alter the plant�s shape. They also stress the host plant, behaving like nutrient sinks, drawing nutrients away from the rest of the plant. Large numbers of galls on a plant can kill the plant."

I will try to show you a picture of mine later. They may be interesting, but dang they are UUUUGLY IMO.