At first glance, I thought it was some sort of strange fluffy pod, presumably left here by cute furry space aliens.
Of course, I have a very vivid imagination.
To my great disappointment, it’s a mossy rose gall. And the funniest thing about it is that I didn’t even know a rose was growing there. I’ve literally* walked by this particular spot on my way to work nearly every day for five years…surely you’d think I’d notice the five-and-a-half foot tall rose bush. In my defense, it’s jammed in with a whole bunch of other grasses and shrubs, seeds randomly blown in years ago and taken hold in the midst of a dense planting of junipers that the landscapers put in nearly three decades earlier. No one has ever pruned or removed any of the odd plantings because you can’t access them – the junipers have made an impenetrable thicket around them. I certainly didn’t notice that the rose had bloomed this summer, but it’s chockfull of hips right now, flashes of brilliant red that catch my eye every time now that I know they’re there. There’s a lesson here about being more observant, I can tell….
Anyway, because my knowledge is a little fuzzy (groan!) about mossy rose galls, I did some reading. If there are any rosarians out there who can offer some more insight, please chime in – I’d love to hear from you! Mossy rose galls are caused by a tiny wasp called Diplolepis rosae (or Diplolepis spinosa), which lay their eggs in the leaf buds of the rose in the spring. The plant reacts to the invasion by producing a gall, which grows all summer and eventually ends up as winter protection for the wasp larvae (clever wasps, using their host like that). The following year, up to 40 adult wasps can emerge from a single gall. I found contradictory reports on how the galls affect the health of the rose – some say the rose is not harmed at all, while others say that the galls draw nutrients away from the rose and that if there are enough galls, the rose will die. The only way to get rid of the galls is to prune them off in autumn, and this article points out that they can be placed in cut flower arrangements for extra interest. (With the larvae still inside? I’m not terribly keen on that. Granted, the writer did make a mention that the larvae are often parasitized by other insects…but isn’t that just swapping one bug for another? I’m not sure I want that particular kind of decoration in the house). Mossy rose galls are most often found on wild roses (such as Rosa acicularis, which I believe is the specimen I found), and frequently rugosas. The wasps that create them don’t go after plants other than roses.
The most interesting part of all of this is that another name for mossy rose gall is “Robin’s pincushion.” Isn’t that an absolutely lovely term to describe a winter housing complex for tiny slimy wasp-babies?
*You may have read that the word “literally“ has been officially granted an additional definition, which contradicts the old one but supposedly has validity because of the rampant abuse – I mean, informal usage - of the true meaning over the years. I’d like to say that I’m literally giddy about how the English language is evolving, but I know I’ve literally misused the word a million times over the years.
Have your roses ever literally (I can’t help myself) been plagued with mossy rose galls or crown galls?
UPDATE (as of September 19, 2013) – There is a great article on Wikipedia about mossy rose galls – it’s well worth checking it out to find out more information about the wasps that cause them. There are also some very interesting medicinal uses (a cure for baldness, anyone?) and historical tidbits listed…plus, some excellent photos. Please link here.