Slugging it out with the slugs

Slugs are the bane of my existence as a gardener. I’m sure many of you feel the same. In the spring they come out of hibernation: voracious eating-machines that know no bounds. They particularly love the tender new shoots of vegetables and ornamentals and can wreak havoc in your garden.

Just last week I was happy to discover that our hostas and farfugiums are producing the first new growth of the season. But as much I love hostas and farfugiums, slugs love them even more. It seems that every new shoot that pokes its head out of the soil gets nibbled on, or worse, chewed to the ground. Not only does this set back the plant’s growth—after all, it needs its leaves for photosynthesis—but might even kill it.

Our farfugiums have had a hard life as of late. First rats ate all the leaves on our Farfugium japonicum 'Aureo-maculatum' and Farfugium japonicum 'Argenteum' to the point where there was nothing left but chewed off leaf stalks poking out of the ground. And now that the plants are pushing new shoots, the slugs have made it their mission to eat the tender bits.

I hate using toxic chemicals in our garden, not only out of environmental concern, but also because we have a black lab who eats everything. I must admit that I was so p***ed off about what the slugs were doing that just yesterday I was considering buying Corry’s Slug & Snail Death granules because in my experience it is very effective. However, because of the way it and similar products are formulated, they smell very attractive to dogs, and our lab would certainly not be able to resist. Metaldehyde, their active ingredient, is highly toxic to dogs, causing seizures, increased heart rate, and very high body temperature, which, untreated, can result in death.

Even though our dog recently mauled my freshly planted canna seeds, I love her dearly and wouldn’t want anything bad to happen to her. So instead of the effective but toxic metaldehyde-based slug killers I once again opted for the safe alternative: iron phosphate slug bait. In the U.S., Sluggo was the first brand, but now there are a few other competitors, including Escar-Go, Worry Free, and Ortho Elementals Slug and Snail Killer, which is what I bought because it was cheaper than Sluggo.

According to the manufacturer, iron phosphate occurs naturally in soil, and unconsumed bait will simply decompose. Iron phosphate causes extreme mucus production in snails and slugs, which in turn prevents them from feeding so they die in three to six days. Sounds horrible, but at least only these slimy pests are affected—iron phosphate is safe for all other critters, including dogs and birds.

I had always thought that iron phosphate-based bait was less effective than the far more toxic metaldehyde products, but a recent study by Oregon State University says that isn’t the case:

[r]esearch at OSU indicates that iron phosphate baits are as effective as metaldehyde baits for controlling our common gray garden slug.

That is good news, and it makes me feel better about shelling out $25 for a 5-pound box of Otho Elementals Slug and Snail Killer. And I will use it liberally, because I’m determined to win the fight this spring!

What do you see in this photo? If your answer is “not much,” you would be correct. The yellow circles are chewed-off leaf stems. Just a couple of days ago, these were new leaves on a leopard plant (Farfugium japonicum 'Aureo-maculatum').

Hosta ‘Stiletto’. The whitish bits are iron phosphate pellets.

Close-up of mangled Hosta ‘Stiletto’. Every leaf on this miniature hosta has been nibbled on.

Even my potted leopard plant (Farfugium japonicum 'Aureo-maculatum') isn’t safe. I’m not only talking about the holes in the leaves, but entire new shoots have been eaten.