Sunday, April 10, 2016


A brown garden snail on one of our rose shrubs.
Snails have become my nemesis. As cute as they are on cards and tchotchkes, they are not so cute when they are eating our roses and the flowers in our window boxes.

Much as I love gardening in the Mediterranean climate of the Napa Valley, I have traded the slugs and aphids of New England for snails and... more aphids.  

Everything might be bigger in Texas but I think California must hold some kind of record for the biggest and most plentiful aphids. But I digress.

Cornu aspersa (formerly Helix aspersa), is a major pest.  Since each snail has the capacity to reproduce and can produce as many as 500 eggs over the course of a single breeding year, it doesn't take much for the snail population to explode if no one is watching.
The flower petals were apparently much tastier than the leaves.
Land snails, or to be more exact, terrestrial pulmonate gastropod molluscs, can denude the gorgeous blossoms of a beautiful primrose overnight.  Here in California, the brown garden snail is the most commonly seen snail and a major problem for nurseries and gardeners alike. 

I was excited to plant this primrose in one f our window boxes.  I had seen it in full bloom at the nursery and it was a beautiful blend of yellow, apricot, and rose.

When we first moved here, the problem in our complex was so severe, the landscape company sprayed the grounds for snails and fleas (another major insect pest in this climate).  The spraying was quite successful in that the flea problem was controlled and the snails were reined in to a manageable number. 

Unfortunately, the spray they used contained permethrins, ordinarily a relatively safe insecticide, but one known to cause health problems for Cavalier King Charles Spaniels. Yep, ours all became ill -- they apparently absorbed the chemical through their paws when they walked on the grass. Nearly three months of persistent diarrhea and occasional vomiting ensued. We got to know our wonderful vets really, really well.

Garden snail moving along the sidewalk near our apartment in the rain.
Snails come out when it rains. They need the moisture to move and to be able to search for food. When it's dry, they camp out in their shells; when it's damp out -- when the dew is thick after an overnight fog, or during and just after a rain -- they come out in force.

They litter the sidewalks and the entry to the grotto that our apartment opens into. They climb the walls, the shrubs, and the trees.

They get onto our patio and climb up the pots and into the plants. Our wonderful garden is the snail equivalent of an all-you-can-eat buffet.

Snail climbing the stucco wall in search of food.
Our best methods of snail control include dusting the area with diatomaceous earth which kills them mechanically by slicing their soft undersides to microscopic ribbons as they crawl over it, and manually picking them off the plants and pots and drowning them in a jar of soapy water.

Fortunately, Steve doesn't mind picking them off because I hate touching the slimy little creatures. I dust both the plants (since DE is also helpful in controlling aphids) and the ground around our patio and when I see a lot of them in the shrubbery, near our apartment, I give the shrubs a dusting as well.

Winter and now spring, with all of the rain, has been very snail friendly.  I am looking forward to the dry season when the snails will be less active. 

For now, every rain, no matter how minimal brings these molluscs out in droves and they do the two things that snails do best:  eat, and then breed and make more snails.

The dense fog we get overnight provides just enough moisture to entice them out to feed, so we need to check carefully on those cool, damp mornings. But once the sun comes out, they tend to withdraw into their shells and hide out until it's wet out again. We check the pots carefully and and collect them into a trash bag and dispose of them with the garbage.

Snails on the walkway approaching our apartment during a light rain this evening.
Snails moving along the walkway and grotto into our building, and climbing the stuccoed walls of the apartment.
Snails on the wet walkways in search of food.
A brown garden snail moving from the grassy area across the sidewalk.

Snails gathering in the grass outside of our apartment.


  1. heh - your garden snails look pretty much like our garden snails, two oceans away....perhaps the early settlers brought them in?

  2. Latest - my magnolia flowered for the first time this year - I have just discovered that it's one and only bloom was set up as a snail nursery!

    1. How astute, Helen! According to Wikipedia, they came to us via the UK!

      Oh no, your magnolia! A snail nursery! How awful! I'm delighted for you that it finally bloomed. I'm betting it's going to be gorgeous in years to come.


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