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August 2006
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October 2006

Thoughts on Snails in Gardens

I have been thinking about how best to deal with imported brown garden snails in the garden. I was out early this morning, and I found one medium-sized one and maybe a dozen tiny ones in my small front garden. I pay special attention to which plants they are climbing. And I also pay attention to which plants they eschew. (That is, they don't chew.)

If I plant a dahlia, any snails in the vicinity are all over it right away. But they aren't at all interested in Mexican sage (Salvia leucantha), feverfew (Tanacetum parthenium), or Jupiter's beard (Centranthus ruber). They never touch my California fuchsia, which is blooming like crazy in the garden right now, or the matilija poppy, the California poppy, or the blue-eyed grass. They aren't interested in the leaves of Pacific coast iris, but will eat the flowers. I planted Oenothera odorata, and they do not like it, but they do like the flowers of gazania.

This morning, I found all of the little snails on the stems and flowers of an Erysimum 'Apricot Twist'. I found the bigger one on Gazania. Duly noted, though, the erysimum has been blooming all summer and hasn't attracted many snails before this.

In zoos, in the areas where vegetarian animals are living, they have to plant things they won't eat. Otherwise, the animals would simply eat up the plants right away, and the results would look depressing and ugly to the human zoo goers. So zoo landscapers are forced to put the animals in compounds with plants that look like they are from the right habitat, but which the animals actually rather detest. (But before you feel sorry for them, remember they get fed stuff they like. So, for example, the Koalas get branches of fresh eucalyptus leaves brought to them as needed.)

Taking a clue from the zoo (the landscaping, not the feeding part) we can plant a garden that snails don't much like. It is already done to avoid deer damage, but many gardeners just keep planting anything they like in gardens where they haven't planned to put much energy into eliminating snails, and are then surprised when snails eat plants up.

So that is part of the equation. If you don't plan to meticulously control snails, don't plant their favorite food. Another important part is that if you do plant something they will eat, snail bait alone is unlikely to be adequate to eliminate snails from a garden. You probably will have to remove some of them by hand. They are, after all, are slow-moving creatures. And in the daytime, they don't usually move at all. They have predictable daytime hiding places where they generally sit quietly. So why not remove them? They hide in places that are rather dry, dark, and have a smooth surface to cling to. Once you find their favorite daytime hiding places, you will find that there are usually some there (as long as there are any left in your garden.) And night or early morning hunts find them right out in the open, and also show you which plants they really like.

When you have taken a snail out of your garden (or returned it to the soil as fertilizer) you have stopped its damage. I can't see why anyone wouldn't want to do this before, and as an adjunct to, beer traps, Sluggo bait, or any other method that depends on the snail finding what you left for it and preferring it to your plants. There has to be a lag time, during which the snail is eating a garden plant. (Bothers me to lie awake wondering if the snails found my new viola transplants first or the snail bait I left in the garden.)

Anyway, that's why these two steps are first on my snail damage prevention "to do list:" 

--watch what they eat. Don't plant favorites where you can't protect them.

--hand pick as much as possible. They have slow life cycles. You really can make a big difference with just a few hunts.

Pardon me, I think I will take a flashlight now and try to get a few more of the small ones, from last summer's hatch, before they find my violas...

Wildly Successful Flowers--Sept. 20

My next public talk will be at Sloat Nursery, at 46th Avenue and Sloat Boulevard, in San Francisco at 6:30 pm, Wednesday, September 20th. The subject will be Wildly Successful Flowers: How to Achieve Great Color with Less Effort. Many of the flowers I'll feature are ones I wrote about in Wildly Successful Plants: Northern Californa.. The talk emphasize plants that bloom freely even in San Francisco's cooler microclimates. I'll be talking about best varieties to grow, when to plant, how to deadhead or cut back when appropriate.

The talk costs $5.00, or is free to Sloat's Garden Reward members. Call Sloat Nursery in advance, at (415) 566-4415, to reserve a seat.

Mite Resistant Fuchsias--My Articles

A number of Chronicle or sfgate readers have asked for more information about articles I have written on the subject of mite resistant fuchsias. There are two of them. I wrote one for the Chronicle and you can find it at: This includes a list of places you can see mite resistant fuchsias growing, and a few, mostly Bay Area, places you can buy them. One of the best places to buy these plants is at the San Francisco Botanical Garden plant sales, which you can learn about by looking on their website at

The other article on fuchsias I wrote was for Pacific Horticulture Magazine, the 2006 July-August-September issue, still on the market as I write this, and surely available as a back issue for a while. It includes a wider list of nurseries that carry the mite resistant hybrids, including mail order sources. You can find Pacific Horticulture in many bookstores and nurseries, or by calling (510) 849-1627. It is a wonderful gardening magazine that applies to California, Oregon, Washington, and Vancouver, and a subscription is only $25.00. Their website, which is at includes tables of contents for each issue, some articles, and a list of the many places that carry the magazine.

I must add that I wrote about fuchsias, both disease resistant hybrids and species fuchsias, in my book Wildly Successful Plants: Northern California, Sasquatch Books, 2004, which is widely available(see cover on right side of blog screen). I chose species fuchsias and mite-resistant hybrids as two of the 50 Wildly Successful plants to feature in that book.

I recently bought a fuchsia gall mite and rust resistant fuchsia called 'Mendonoma Belle" from the SF Botanical Garden, for a garden in the Sunset. It is such a pretty, bushy plant. The flowers are red and purple, rather larger than those of F. magellanica flowers, and with longer sepals (the outer wings). I look forward to watching it become a large and pest-free garden plant.

Butternut/Moschata Squash--Yum!

A comment to my last entry contains a question about growing butternut squash in San Francisco. This is one of the best winter squashes to grow in California, since it is in a species of squash that is relatively resistant to powdery mildew. When you are looking in a seed catalog, or on a seed packet, look carefully to find the scientific name of the squash variety you are considering. Look for the name "Cucurbita moschata." It may be called butternut, or could have a different name, but it will share the powdery mildew resistance trait.

I don't have space to grow many winter squashes, so don't grow them every year, but if I were looking, I'd start with some seed sources I trust, and see what they carry. I'd look at,, and

Most butternuts have the typical bottle shape, but there are other shapes. Territorial has a round one called 'Long Island Cheese' and, which sells only heirloom varieties, carries a round one called 'Kikuzu'. Both of these companies also sell 'Futsu Black', a squat rounded type from Japan.

Another C. moschata is tromboncino squash, one that is eaten most often as a summer squash, when it is very young. It is long and pale green at the stage you eat it, a bit firmer than a zucch.

All of these squashes can be trained up a tall trellis. They may try to twist away from the trellis and so have to be tied to it as they grow, but will usually attach with at least some tendrils. If you intend to grow the winter squash types, you may need to hang the fruits in a soft cloth sling as they ripen, since they will get pretty heavy. Old nylons are often recommended, if you happen to have them, though old tee shirt material should work fine too.

My experience is that the coldest, windiest parts of San Francisco are a challenge for these crops, but in the parts of the City that get more summer sun and in wind-protected garden locations where heat can build up a bit, they can be reasonably productive.

For winter squash to have time to make mature fruits, best to plant in May. I was very late last year getting in tromboncino--not till mid July. Even in the Mission garden where I grew them, this was pushing it, but I started them inside, and then planted them in large bottomless black plastic pots full of potting mix to keep the soil as warm as possible, and got a few fruits before the inevitable fall decline. Don't recommend starting so late though.

You need bees for pollinization of all of these squash. Planting some borage or cerinthe will attract them. Both reseed and can be a bit pesty, but at least they are pretty. And the flowers of the borage are edible, tasting like cucumber, so they can be welcome in salad or floating in iced tea.