What's the (adaptational) point of moss?

I’ve been giving this topic a lot of thought lately. What started me thinking of it is rose weevils. I loathe these things. But I’ve noticed that they do far more damage to non-mossed than to mossed roses. Does mossing serve a protective function? Either physically, or by making a naturally bug-repelling smell? Or maybe it just makes crawling on the stems too much work?

This got me thinking about aphids. Unlike rose weevils, in my garden aphids appear in about equal numbers on all the plants. I got out a magnifying visor and watched the aphids on the moss roses, and have to wonder, from what I saw, are they using the moss resin as food? They appear to be eating it. Is moss a way for a rose to say, “Here, I’ll give you something to eat if you just leave me alone”?

This thinking, apart from making my brain hurt, makes me really watch ‘Janjin Malgai’, a.k.a. Mongol’s Hat. I think those [shocking bad word] beetles fly, but… will they attack the buds?

The mossing is meant to foster a symbiotic relationship with people… drop-dead gorgeous mossing and that amazing pine resin aroma almost guarantees I’ll put them where I can fuss over them, run my hands through the moss and be as happy as a cat in catnip, protect them, and tell them I love them… definately a survival strategy to force its human slaves to look after it :wink:

On a more serious note… I’ve not noticed as many aphids on ‘Henri Martin’ here. I was wondering if it was actually an insect deterent. On a down side, there must be an adaptive disadvantage in mossing due to its propensity to develop mildew. On another rose I have, a multifora rose, that produces densely glandular foliage and buds with that same pine resin fragrance I never see aphids. It is thornless save for a few prickles on the underside of the rachis. I was also wondering whether the resin had antimicrobial properties developed in response to the higher incidence of mildew… do all mosses produce that pine resin fragrance and thick resin? I only have ‘Henri Martin’, ‘William Lobb’, and ‘Dresden Doll’ and only ever see mildew on ‘William Lobb’ (though to be fair if ‘Dresden Doll’ kept its foliage for long enough maybe I’d see mildew).

Interesting line of thought, Fa! If, as has been shown, that European OGRs sprang from Gallica, Fedtschenkoana and Moschata, my feeling is the “mossing factor” might possibly have come out of Fedtschenkoana. (see linked photo) My DLFED seedlings have expressed everything from completely smooth peduncles, ovaries and sepals to a rather “mossy” one, DLFED 3.

Usually, bristly plant parts like these function to trap moisture from fogs and dews, particularly in more arid environments. Stellata, Persica and Minutifolia all express them and are from rather arid areas, and especially in the case of Minutifolia, the small foliage and bristly plant both serve not only to harvest water from coastal fogs, but reduce transpiration from excessive leaf surface.

The bristles may also function to help prevent vermin from eating the reproductive parts of the plant as they form formidable armature once the hips begin to swell and dry. I can also see how the bristles function as Velcro, adhering to the fur (and clothing) of any person or animal getting too close.

My impression is today’s “mossing” is an altered expression of these bristles and serves little purpose other than being decorative, as there would be definite drawbacks to trapping too much moisture where moss roses grow more fequently, as well as providing extra footing for fungi spores. They impress me as the rose’s version of our tonsils and apendix, something which served a useful purpose at one time, for specific ancestors in specific locations, but which seems to have outlived its original purpose. The rose obviously has the ability to either express, or not express the trait to a wide degree. This would allow it the ability to adapt to its environment changes, should it become necessary. I would think the mosses would probably have died out in Nature had it not been for our “unnatural selection” maintaining them.

It’s a good guess that moss is a deterrent to some things, but perhaps not aphids. They are strictly a sucking insect. They build a pipe into the phloem of the stem and withdraw nutrients. People are trying hard to understand what they might insert in the building process. It is known that they allow viruses to enter the plant and also RRD is transmitted by an aphid relative I believe. Clever folks claim to have put siRNA into artificial medium for aphids to suck on, and that way knocked out specific genes of the aphid.

The resin could be toxic to aphids, even if taken externally and not through their sucking. Or it could be nasty to walk on. It does appear that some roses are more susceptible than others to aphids as seedlings. I had a terrible time with some last spring, and again this year, but some plants seemed rather resistant. Very hard to do quantitative studies with changable weather.

Slightly off topic, but I have this season learned the hard way to spray for aphids on my young rose seedlings (I do not spray roses for any other bug/disease no matter how precious).

Fara, are you propagating Mongol’s Hat?

Well, it certainly fosters a symbiotic relationship with Fa! :smiley:

@Kim, Fedshcenkoana, I must have it! Protecting reproductive parts makes a lot of sense, especially protection from these $&#@!! beetles! As for hairiness, almost all the plants that are native to my area have moderately to very hairy leaves, and I’ve noticed the roses that grow best in the “wild” here – though not the native species, curiously enough – have very hairy leaves. One I bred myself, “the Hippy-Dippy Rose,” has leaves so soft all you want to do is touch them. Alas, the flower… needs work.

@Don, Yes, I’m propagating Mongol’s Hat from suckers, and I have totally and utterly failed to propagate it from cuttings. Probably something due to my technique, as I have no luck propagating mosses from cuttings. I should have a few plants ready for new homes this fall.

Here’s a picture of the entire plant of ‘Janjin Malgai’/Mongol’s Hat, next to some violas and pansies to give scale. (Well, okay, because they happened to be there, but hey.) It suckers but the suckers stay very close to the main plant, so I can see it as a really nice little ground cover. Of course, it only blooms once a year, but after the first bloom it’s way too hot to sit around in the garden anyway. The plant is four years old.

[attachment 734 mongolwhole.jpg]

Fara, I have been thinking along the same lines - sawflys are what I am thinking. They target young growth for depositing their eggs. Kind of hard to deposit them with all that mossing and prickles in the way. As for aphids, well the ants seem to be swarming all over the roses that have aphids and appear to be dealing with the aphids.

Fa, how much acreage do you have? LOL! You’re welcome to pieces of Fed. as soon as it puts out enough growth to have successful suckers. It’s in a dry area with very loose soil (the whole hill is, in fact!), full sun, lots of gopher activity though it is caged; smack in the middle of what used to be an enormous oleander hedge until Oleander Leaf Scorch took it out, so there is a great deal of dead oleander root and litter in the soil, but it’s the best I can give it and keep it watered.

There are also the Dottie Louise X Fed. and Orangeade X Fed. hybrids, as well as a number of 1-72-1DLFED, Cherry ParfaitDLFED and one or two Nichole Carol Miller X DLFED hybrids.

I’m using the Repeat DLFED pollen on many things including the 1-72-1Hugonis. I’m also putting Secret Garden on the DLFED and CPDLFED seedlings; several polys, including Mignonette, Wlid Dancer and Bashful on the DLFED and 0-47-19DLFED as well as Inner Wheel X 0-47-19, just to see what will happen.

Those are some really nice crosses! If you ever get suckers from Fed, I’ll trade you for some suckers from here. I’m going to be doing a lot of work with arkansana and woodsii sp. this year. Who knows what I’ll get!

I had Arkansana and it is very pretty, but addicted to mildew here. I accidentally discovered I could force it to rust any time of the year by drying it out. The only Arkansana hybrid I’ve ever grown which didn’t rust here was Morden Blush. Woodsii, I had years ago but had to give it away due to room. I now have a sucker of Wooley-Dod’s Rose to play with and hope to get the double Xanthina and Hugonis flore plena IF I can ever find anyone who has suckers of the blamed thing. There are no commercial sources for it anymore. Vintage MAY have a mother plant. Gregg is looking.

Arkansana with mildew? Good grief, I thought Arkansana was immune to everything. Must be a regional thing. Arkansana is native here, and we don’t believe in either humidity or oxygen at this altitude…

I’m trying to collect as many species as I can. At this rate I may need to evict the horses from one of their pastures to get more room.

I’m sorry, I mistyped. RUST is the issue with Arkansana here. The only form of it I’ve grown (still do) which has never rusted is “Peppermint”. Roxburghii is very chlorotic as is Fedtschenkoana. Hugonis is bullet proof, no issues. Bracteata is just fine. Clino-Bract tends toward chlorosis as can Minutifolia. Stellata mirifica had chlorosis issues in the soil but not canned. I haven’t attempted to correct any of the issues in hopes they would resolve themselves or just die out. Getting products to where they grow is an issue. It’s difficult enough just keeping them watered!

Other than the above stated chlorosis, there haven’t been issues with those species other than the mother plant of Mirifica just curling up her toes last year shortly after being planted. Fortunately, there is ONE self seedling of her to replace her.