Sawflies

Macremphytus tarsatus, Macremphytus tarsatus, Macremphytus tarsatus.  Roll that off your tongue a few times … difficult … frustrating?  Explains how difficult it is to control sawfly – the common name for Macremphytus tarsatus, and how frustrating it is to walk outside to peruse your foundation plantings to find your red twig dogwood totally bereft of leaves.  And I do mean bereft … nude … free of vegetation … leafless … get the picture?

It seems I have been fighting to grow red twig dogwoods for about a decade now.  I was drawn by the lovely magazine and nursery catalog photos of the red  clump of branches standing tall while surrounded by blankets of snow.  What a cool contrast, I thought.  This would look great against a backdrop of blue/gray siding.  So I bit, I bought, I buried.  I waited, I watched, and after the first snow I was convinced I had found a striking, interesting focal point for one of my front yard beds during winter months.  In theory, the red twig would grow to about 5 feet tall and 4 feet wide, be covered in variegated cream and green – or solid green – leaves in spring, summer, and fall, thus acting as a center shrub on either side of my rather traditional looking house.  In theory, these shrubs would be an anchor for summer blooming perennials, and in the winter months their red twigs standing in pure white snow would be a focal contrast to the neighboring rhodies.

In reality, this is all a bunch of bunk!  Deer love to eat red twig dogwood leaves in summer – even though they have a rather unpleasant, fuzzy underside.  Deer love to eat red twig dogwood stems in winter – particularly when so much of their normal fare is buried under snow.  But deer browsing was not too bad.  Then I discovered sawflies.  These relatively attractive larvae – as caterpillars go – simply crave red twig dogwood leaves.  Just when I’m beginning to enjoy the mid to late summer fullness of my dogwood shrubs, the sawflies show up and totally denude the stems.

P5310637So a common sense gardener would simply control these pests.  I’m a common sense gardener … so I did some research.  Control generally means hand picking.  Ok … I do this with other annoying creatures like Japanese beetles and slugs.  But each dogwood leaf can have dozens of sawfly caterpillars grasping onto the undersides of leaves … every leaf.  And, by the time you realize you have a sawfly infestation, it’s too late.  The leaves are nearly gone, as you can see in this not too great photo, but you get the picture. Notice those twigs branching off the main stem?  Each was once surrounded by a leaf. (I could have spent more time getting a better photo, but I’m done with the whole sawfly thing … I’m just plain annoyed.)

So I think I’ve come to my senses.  This yard  – at least the foundation bed in front of the house – is simply not the place for red twig dogwoods.  This fall I’m digging them up.  Rather than chuck them I’ll probably plant them elsewhere and tell them they are on their own – left to ward off deer and sawflies as best they can.  If they don’t survive the uprooting, I’m ok with that .  Life is just plain too short for annual fights to grow something that simply does not work.  Will I miss the winter contrast?  Absolutely.  Will I seek an easy care, insect resistant, deer resistant replacement?  Absolutely again. 

But, the bottom line – or I could say the last leafless red twig – is whatever I plant will be easy care, and deer and sawfly resistant.

9 comments for “Sawflies

  1. August 28, 2009 at 7:43 am

    Joene,

    I had a nasty infestation of sawflies this year too. They decimated one of my red twig dogwoods and did some minor damage to the other two. And, just as you mentioned, it seemed to happen overnight.

    I’ve had redtwig dogwoods in my garden for about 15 years and this is the first year I’ve had to deal with sawflies so I was completely unprepared. By the time I first saw the damage, the caterpillars were about ready to hatch and those that were left on the bush were either moving along the leaves or huddled closely under a leaf. They gave the bush the effect that it was moving. It was disgusting and fascinating at the same time.

    Like you, I did my research and found that nothing was going to kill the larger caterpillars, so I too handpicked them off. There were so many of them that I actually ended up cutting off large pieces of the shrub and ptting them into hot soapy water. A completely disgusting task. I also doused the base of the shrub with hot soapy water to kill all the caterpillars that jumped for safety!

    On the two shrubs that had minor damage because the caterpillars were still young and could be killed by an insecticide, I sprayed a Bayer product. While I hated to use a chemical insecticide in my garden I was so frustrated by the infestation and I wanted to make sure the adults didn’t hatch and then overwinter in my yard and start the cycle again next summer.

    This has definitely been an interesting year in the garden!

  2. joenesgarden
    August 28, 2009 at 3:08 pm

    I’ve had sawflies before, and just as bad. But this year’s infestation is the last straw for my redtwigs. They don’t offer enough year round bang for the locations I’ve given them. I haven’t figured out yet where their new home will be, but it will definitely not be in a location that garners constant attention.

  3. August 28, 2009 at 3:14 pm

    how about you just stick some red spray painted sticks in there to get the same result. I know a guy who could even paint them for ya

  4. joenesgarden
    August 28, 2009 at 3:38 pm

    Now … there’s an idea.

  5. fern
    August 29, 2009 at 9:47 am

    Hmmm. I planted red twig dogwoods this spring, but immediately fenced them in to ward off deer; it doesn’t look pretty, but i thought i’d give them a fighting chance.

    that’s been my modus operandi when planting new shrubs; fence them in for several years until they’re big enough ti withstand deer grazing. So far, it seems to have worked.

    I hadn’t known about the sawfliers, however, i experienced a similar caterpillar infestation (small black ones) on 2 service berry saplings. Every spring, both would get infested and totally defoliated, despite hand-picking. Both saplings were stunted in growth for about 5 years, and i blame these worms. Then, inexplicably, one of the trees really took off this spring, putting out a nice canopy of leaves and looking for once like a healthy young tree. It didn’t get touched by the worms this year, even though it’s just 10 feet away from the other serviceberry, which did once again get deluded with these little worms which roll up inside the leaves.

    So maybe there’s hope?

  6. joenesgarden
    August 29, 2009 at 7:48 pm

    Hope? Yes, that they will survive elsewhere in my yard. They are taking up valuable real estate right now, and don’t offer enough benefit in return. Glad your service berry tree is finally taking off.

  7. KD
    November 3, 2009 at 11:45 am

    HI, This may be a bit late, but if you’re set on Dogwoods, there was a research paper published in 2007 that discusses which dogwoods Sawflies like most and which they seem to stay away from. The redtwig dogwood is among their favorite (of course, right?), and the ones that are least susceptible don’t have the showy red twig color. But either way, here is the link for the paper if anyone wants to check it out. Good luck!
    http://plantsciences.utk.edu/klingeman/pdf/DW_Sawfly_on_Cornus_spp_JEH25_134-138.pdf

Leave a Reply

%d bloggers like this: