Identification: Mossy Growth on Windowsill Geranium - Harmful?!

Discussion in 'HortForum' started by aphelia, Mar 21, 2013.

  1. aphelia

    aphelia New Member

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    Hello!

    I'm new to the forums, and joined primarily because of this troublesome issue. I have two healthy white geraniums growing in clay pots on the windowsill in my kitchen. The plant on the left (see photo) is the older one that I grew from seed about five years ago and the one on the right is a descendant that is around two years old.

    Both were potted with the same soil mix at the same time (two years ago). I never had any problems. They are growing a bit tall for the size of their pots, and probably should be repotted, but these pots fit the windowsill and they seem happy there :) These photos were taken today, with their new Spring blooms. (The blue thing is a glass marble; I put one in every pot for luck, but didn't think to remove it when taking the photos - sorry about that!)

    My problem is the older plant on the left. As you can see there is a feathery short green layer of what I suspect is moss (and hope very much is not something serious) growing around the plant. I have no idea where it came from! I'm assuming it came through the window via airborn spores but if that was the case the younger plant is closer to the screen and should also be affected. I haven't been able to identify the moss type and I would really like to know if it is harmful to the plant! The plant does seem happy but it isn't holding its water the same and I don't know if the moss affects this?!

    I have done some looking around on the internet and there seems to be conflicting opinions about moss and houseplants. Some seem advocate to it for a more decorative look, and I have read that it can be beneficial for retaining water (although that doesn't seem to be the case here). This was the reason I left the moss alone when it first started to grow, although it is multiplying quickly now and will soon overwhelm the soil I think. On the scary side, I have read that the moss smothers the soil and blocks the sunlight available to the plant, and that it turns the soil acid and will eventually kill the plant.

    Any help in identification and advice for elimination (if needed) would be very much appreciated! These two geraniums have sentimental value for me, particularly the parent plant (which I grew from seed for my Grandma for Mother's Day many years ago and ended up taking home when she moved) and I would very much like to save them. Thank you for reading!

    P.S. I am asking this question here rather than the houseplant forum because I think the invasive moss (?) came in from outdoors and so outdoor gardeners might be more familiar with its nature and how to eliminate invasive plants in general :) Hope that's okay!
     

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  2. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    I have the same moss growing in some of my containers in various degrees. The plants don't seem to be affected by it.
     
  3. lorax

    lorax Rising Contributor 10 Years

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    Moss won't hurt your geraniums (which, incidentally, will do better in the slightly acidic environment that the moss produces). What it does do, however, is increase moisture retention in the soil once it's established over the full surface. This means you will have to water less frequently once the moss has covered all of the soil.

    Yours looks like one of the common Sphagnums.
     
  4. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Moss is harmless, but it can be an indicator that you are over-watering (moss likes plenty of water, most potted plants don't like so much).
     
  5. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    Looks more like an Atrichum to me, which is a great colonizer moss.

    Species of Sphagnum in all(?) cultivated situations will be an intentional addition, likely used by someone growing carnivorous or bog plants.
     
  6. lorax

    lorax Rising Contributor 10 Years

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    Daniel - it's more from my personal experience south of the equator, where Sphagnums will colonize pots and indeed any unclaimed soils in an opportunistic manner. They're a tremendous (pest? I encourage them, but other people hate them) in my banana garden. I hadn't thought they'd be any different in the northern hemisphere, but apparently they are!
     
  7. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    Ah, I didn't consider tropical environments. Yes, that makes sense!
     
  8. aphelia

    aphelia New Member

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    Thank you all so much for your replies!

    @ Junglekeeper - that is very encouraging to know :)

    @ MichaelF - You may very well be right. Since the geranium has just started blooming, it's been thirstier than usual, so I've been watering it more often (every second day instead of twice a week). Maybe I shouldn't be doing this?

    @ Lorax and Daniel Mosquin: I really appreciate the help! I think it may very well be an Atrichum (thank you so much Daniel!). But I do have a silly little question (I'm new to houseplants, and completely unfamiliar with mosses!):

    Since it's not harmful either way (and I am so relieved about that! thank you!) and can stay, how might I go about transplanting some into the adjacent pot? Should I just dig out a little bit and put it in the other pot? I know you said it's a good colonizer, but since it hasn't hopped over on its own by now I don't think it's going to! If I'm going to keep the moss, I'd like both pots to have it, especially since there may be advantages to the geraniums for doing so.

    As a side-note to the Atrichum vs. Sphagnum debate:

    I should add something I did not think to earlier (sorry about that). My yards (under the window, and at the back and front) are rather unusual in nature. They are wild and completely uncultivated. I'm renting, have been here for several years, and the fill that was used obviously came from elsewhere, and wasn't standard. I have wild strawberries, plenty of young trees and bushes (maples, alders, ash, rowan, fir, spruce and goodness knows what), clovers, thistles, long tall grasses of several distinct types, some small wildflowers, and different types of moss of varying colours (one is black, another burgundy, at least three distinct varying greens, one yellow-white), some of which are Sphagnum I believe. I also have lichens on the rocks scattered amongst the chaos. It is also a very boggy area, and some of the plants are things I recognize from local marshes. Most of these plants are unusual for the area (I live in the suburbs, with chemically treated green lawns everywhere and very few ornamental gardens) but common in the province.

    One of the reasons I've gotten interested in botany lately is trying to figure out what exactly is growing in my backyard :)
     
  9. lorax

    lorax Rising Contributor 10 Years

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    OK - if you want to encourage it in the other pot, just pull a piece out of the current colony and move it over. It will, slowly but slowly, establish itself.

    And over in the "fungus moss and liverwort" forum, please show us your mosses!
     
  10. aphelia

    aphelia New Member

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    Thanks Lorax! That's great to know :) I'll try to take some pics of my weird yard when the snow finally clears. I had no idea that there was so much to mosses and it's amazing to me that such little organisms are so hearty and persistent ;) Thanks again for all your help, in both this thread and the others!
     

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