By Jim McCausland, Sunset Magazine

When gardeners have asked me about deer control, I've always responded that a tall fence is the only sure thing. It still is, but a new repellent comes close in effectiveness. Called Bobbex, it was shown to be more effective than nine other commercial repellents (including coyote urine) in tests run by the University of Connecticut last year.

Made from a combination of ingredients that blends the scents of rotten eggs, garlic, fish, clove oil, and vinegar (among other things), it works by mimicking predator scents, so it is classed as a fear repellent. It also tastes awful, so deer have at least two reasons to stay clear of it. You'll want to bring cut flowers in from the garden immediately before you spray, or at least a day later, after the odor has had time to dissipate.

Bobbex requires reapplication every couple of weeks. Following a slightly less frequent application regimen, the University of Connecticut gave it a 93 percent protection index (with a fence at 100 percent, and the control—no protection at all—at 49 percent). Other repellents scored across a range that ran from 50 percent to 83 percent. Coyote urine earned only a 53 percent protection index (and how would you harvest it anyway?).

The repellent trials were done by measuring damage done by white-tail deer browsing Japanese yew (Taxus cuspidata). West of the Cascades and Sierra, most deer in the West (like the one pictured above) are blacktails, but the difference between them and their eastern cousins should be negligible, at least in dietary issues.

You can buy Bobbex from local retailers (but not big box stores) and such online sources as Amazon.com.

By Sharon Cohoon, Sunset senior garden writer

I didn't have a photograph of the crape myrtle allee in bloom for the post about Rancho Los Alamitos I wrote recently.   So I used one showing how the walk looked in winter color.

The same photographer just sent me a more current image.  Here's how the walk is looking now.

Both photos by Cristina Salvador Klenz

And, while I'm at it, let's clear up a possible confusion.  The Rancho still calls this the Oleander Walk, despite its being lined with crape myrtle, because that was what was here originally.  The trees, planted in 1929, died from oleander leaf scorch.  A second planting did as well.  So the Rancho conceded defeat and substituted crape myrtles which create a similar effect.  In another year or two, they should arch over the path creating a cool tunnel.

***

Last month I wrote about an Knoxville, Tennesse artist, Lauren Karnitz, who was creating flowers out of recyclables and whose primary buyers were green wedding customers ordering centerpieces, corsages, and boutonnieres. 

A San Diego bride-to-be, who saw that post, asked if the artist could also do flowers for a wedding cake.  Here's a few of the cakes Karnitz has done since.

By Jim McCausland, Sunset Magazine

I once took a wine-tasting class at the Vintner's Club in San Francisco, where a room full of people, me included, mapped their palates. It worked like this: All of us had five glasses of the same wine in front of us, but each glass had a different level of, say, sulfur, from near zero to near toxic. As we tasted the wines in sequence, each of us noted the first glass that had a discernable sulfur taste, then noted the glass that had too much to be enjoyable. Then we repeated the same test for sugar, tanins, and so forth, until we fully understood our sensitivities to the different flavor componenst of wine.

The really surprising thing was how varied our responses were. Some couldn't even discern sulfur at levels that made the wine taste like rotten eggs to the rest of us. And a few of us would pucker at levels of tannins that went unnoticed by others.

The primary message was that we all have very different taste thresholds, so the same wines actually taste very differently to different people. The secondary message occurred to me much later: the same must true of deer. That's why the astilbe that one deer shuns is a perfectly acceptable munchie to another.

For this reason, experienced gardeners tend to be skeptical about lists of deerproof plants. But such lists are not without value. Given the choice, deer will always take roses over rhododendrons, for example, and apple leaves over ferns.

If you want a good starter list, pick up a copy of 50 Beautiful Deer-Resistant Plants by Ruth Clausen, with photography by Alan L. Detrick (Timber Press, Portland, OR, 2011; $19.95). Even apart from its gorgeous photography, which will make you want to eat the plants, the book has much to offer. Instead of just presenting plants as being deerproof, Clausen rates them on a 1–10 scale, and gives examples of when they might be most at risk.

Because the book was written from an east-coast perspective, Clausen's experience is with white-tail deer. In the far West, we have mostly blacktail deer and closely related mule deer. But still Clausen's list rings true to me, and the book can give any gardener an advantage against our most common large plant pest (with the exception of elk and moose, as our Alaskan and rural Northwestern friends are sure to point out).

By Jim McCausland, Sunset Magazine

                                                                                             —Leonardo da Vinci

As rose season gets under way, I anticipate the flowers with delight and a series of rose diseases—black spot, mildew, and rust, mostly—with a bit of concern. But not much. When a rose doesn't perform for me, I tear it out and replace it with something that has a better immune system. There are lots of choices, new and old. A couple of personal favorites, besides those on the list below, are 'Leonardo da Vinci' (pictured at top) and 'Walking on Sunshine', the 2011 All-America Rose Selections winner (below).

There are a couple of good things to remember about disease resistance. First is that most roses do pretty well the first year you have them in the garden, so it's best to wait awhile to judge performance in your garden. Second is that disease strains are quite variable, so a rose's resistance may vary both regionally and over time.

Here's a list of some other disease-resistant roses in different categories; most have been in available for years. This was compiled by Oregon State University.

Hybrid tea
‘Electron’
‘Just Joey’
‘Keepsake’
‘Las Vegas’
‘Silver Jubilee’
‘Voodoo’

Floribunda
‘Europeana’
‘Impatient’
‘Liverpool Echo’
‘Matangi’
‘Playgirl’
‘Playboy’
‘Regensberg’
‘Sarabande’
‘Sexy Rexy’
‘Showbiz’
‘Trumpeter’
‘Viva’                                                                                                               —Walking on Sunshine

Grandiflora
‘Love’
‘Tournament of Roses’

Climber
‘Dortmond’
‘Dublin Bay’
‘Royal Sunset’

 In addition to the roses listed above, check out this list put together by Oregon State University master gardener Pat Patterson.

By Jim McCausland, Sunset Magazine

As home remedies go, this one has a certain strange logic to it: Master Gardeners who used Bounce fabric softener sheets noticed that they had fewer mosquito problems than gardeners who didn't—especially when they kept the fabric softener sheets in their pockets. Though that has been neither confirmed nor disproven in the lab, it made scientists wonder whether Bounce would repel fungus gnats, so they tested it. (Fungus gnats breed in potting soil. The males merely drive gardeners mad, while the females produce offspring that eat plant roots.)

In the December, 2010 issue of HortScience, researchers reported on a project done at Kansas State Univeristy that showed that, yes, Bounce does repel fungus gnats.

There is sometimes a great distance between what succeeds in controlled lab experiments and what works in the real world, but you can download the research paper here and decide for yourself whether Bounce belongs in your insect control arsenal—or just in your clothes drier.

By Sharon Cohoon, Sunset senior garden writer

Photograph by Andrea Gomez, Sunset staff photographer

Todd Porter and Diane Cu, the young couple shown below, are fanatics about citrus.  They have 21 different types growing in their backyard in Costa Mesa, California.  Their trees produce about 600 pounds of fruit a year.  More than just two can consume no matter how much they like citrus.  So Todd & Diane invite friends in regularly to share the harvest.

Read more about their citrus harvest parties, their favorite fruits, and their growing tips on page 50 of the February issue or here, and some of their favorite citrus recipes in the article on page 87. (The couple are big foodies as you can tell from their blog, White on Rice.)

Todd and Diane, however, are well aware they live in an area where citrus is under quarantine to prevent the spread of a new exotic pest, the Asian citrus pysllid.  Moving backyard fruit trees, leaves, cuttings, and fruit from infested areas to non-infested areas is the the primary way the insect is spread. So Todd and Diane don't share their fruit with anyone outside their quarantine area. And that's important.

The danger of the citrus psyllid is not the insect itself but the fact it is the carrier for a bacterial disease known as Huanglongbing or citrus greening disease which is deadly to all varieties of citrus.  There is no cure for the disease to date.  It has already destroyed citrus production in many parts of the world.  We don't want to be next.

Read more about the quarantine and the citrus psyllid on the the California Department of Food and Agriculture website.  Parts of Arizona are also under quarantine.  There is a map of the quarantined area on the CDFA website.

You can also find pictures of the damage this aphid-like insect causes and additional information on our previous post about this subject.

By Johanna Silver, Sunset test garden coordinator

This recent article in the San Francisco Chronicle caught the eye of our garden department. It speaks of bug hotels, a European tradition that involves creating perfect mini-environments in which beneficial bugs can overwinter.

Design: Colleen Smith / Photo credit: David Paul Morris & SF Chronicle

Urban Hedgerow, an organization dedicated to creative ways to increase wildlife habitat, is partnering with local artists in hopes to amp up the popularity of bug hotels in the states. 

The design can be as simple as hanging upturned terracotta pots from a branch and filling them with pine needles, but with examples as creative as these, you might find yourself dreaming of your own bug chateau.

Photo: Lisa Lee Benjamin

Here are the instructions from the article in the Chronicle:

How to make a bug hotel

Insects are fairly undiscerning when it comes to lodging, says Urban Hedgerow founder Lisa Lee Benjamin, "Generally, they like dark crevices that are in a south-facing location so they can stay warm. Small sticks, logs, hollow spaces like straws, bamboo and reeds, oat or wheat straw, mulch and bark also make good bedding material. They also require nearby plant matter and nectar sources for food, a little bit of water to drink and, depending on species, anywhere from feet to thousands of miles to roam," she says. "Think of these hotels as small altars to the zillions of bugs that are essential to our planet's survival. It is the least we can do."

Step 1. Frame: Create or find a structure or frame to contain your bug hotel: a large piece of pipe, a box, a picture frame, a bicycle wheel or other found object, all preferably 6 to 12 inches deep, will do. The frame can vary in size and can either hang or be freestanding in the garden.

Step 2. Compartments: Find or build structures to create compartments on the inside of the frame. Pipes can be welded together or compartments created with wood, bottles, pots, etc. Make sure that these are secure and attached to the frame.

Step 3. Site: Position the bug hotel in its new home. Find a south-facing spot in your garden, preferably by some forage plants and nectar sources.

Step 4. Gather: Grab a pair of pruners. Search around your yard or neighborhood for fill material, such as weeds, sticks, bricks, old hose, leaves, burlap, rolled paper, string and anything else you can think of to fill each compartment. Think of creative ways to organize and arrange the materials, cut on angles, woven together or stacked. Remember to have fun and that there is no right way. Think like a bug and you will probably be spot on.

Step 5: Observe: Now see who shows up. You can look up your visitors on www.whatsthatbug.com.

Beneficials that would love a reservation include solitary bees and lacewings, and ladybugs.

My one concern is whether the crevices might also provide winter hideaways for less-than-desirable insects. The article mentions ants as critters like the nooks and crannies of a hotel. Last I checked, ants are not on the beneficial list. But truth be told, these insects -- beneficial and otherwise -- can manage without a bug hotel, so I think this is better viewed as an art project rather than serious habitat creation. 

I am going to play around with creating a few of our own for the test garden. I'll definitely post some pictures. And be sure to send yours to garden@sunset.com.

By Jim McCausland, Sunset Magazine

We don't have many snails in the Northwest, but their slug cousins range over the garden like the sheep on a thousand hills. There are at least three kinds of slugs you should be familiar with for reasons that quickly become apparent.

•Banana slug (Ariolimax columbianus) is native from the mountains of Southern California to southeastern Alaska, so leave it alone. Though its diet includes both living and dead plants, plus fungi and animal droppings, it never does enough damage to reach pest status. In fact it rarely shows up in my garden, though the forest beyond my back fence is full of them.

Besides, it's a very interesting creature. Color is often bright yellow (thus "banana" slug), especially farther south in its range, but it can also be dulll yellow-tan (left), brown, green, or white, sometimes with big black spots. Other slugs also come in some of those colors, so you have to look more closely to get a good i.d. Two things help. First, this one is the biggest slug in the world, sometimes reaching 10 inches long at full stretch; and second, the back of this slug is topped by a sharp ridge that looks like an upside-down boat keel.

Banana slug's genus name, Ariolimax, is a combination of the names of the two following genera, Arion and Limax, because it has traits in common with them (the keel of the leopard slug and often the color of the European black slug). When you touch these, you'll find that the slime is very hard to remove; salt helps. Yet you'll notice that when banana slugs cruise through the duff, dirt, and leaves of the forest, they're usually pristine, with nothing at all sticking to them.

•Leopard slug (Limax maximus) is a 4- to 8-inch, gray European slug whose black spots suggest, for those with vivid imaginations, the markings of a leopard.

Leopard slug does eat garden plants, but it also dines on other slugs. I've never personally seen leopard slugs involved in this sort of cannibalism, but I approve, so I don't have these on my hit list.

Leopard slugs tend to return to the same place every night. Like other slugs, they're hermaphroditic. But unlike the other slugs, they mate while suspended from a long thread of slime. In matters like these, one must be philosophical. Chacun a son gout.

•European black slug (Arion ater) is the bad boy of the garden, mowing down seedlings as they emerge, so you think "bad seed." Bad seed alright, but it's the slug, not the cabbage. They also eat dead vegetation, fungi, and carrion (especially their squashed brethren), and are themselves eaten by frogs, toads, moles, mice, shrews, snakes, and carnivorous beetles.

Most of my European black slugs, incidentally, are brown. Their backs are rounded, without the sharp keel that marks the other two slugs described here. Mature size runs 4 to 6 inches.

A couple of years ago I fantasized about being able to kill these creatures by just looking at them. They wouldn't last long, I imagined. Then I realized that I could test this theory by killing every one I saw on my property. I did it faithfully, no exceptions, for about 18 months. It seemed to help, though I never got rid of them entirely. I suspect that the paucity of slugs just creates a biological vacuum that draws in slugs from surrounding gardens.

Having written this, I can still say that European black slugs are individually fascinating. Just look at the colors and textures surrounding the breathing hole of the one pictured below. The orange-striped fringe on the edge of the foot is quite outré. Shoe designers take note.

By Sharon Cohoon, Sunset senior garden writer

Photos courtesy the California Department of Food & Agriculture

The worst known pest of palm trees, the red palm weevil, was detected in Laguna Beach, California earlier this month.  This is the first detection of this insidious palm tree pest in the United States.

Here's is what the exotic pest looks like:

And here is the damage it causes. Infestations usually kill trees.

More information about this pest follows, courtesy of Steve Lyle, Director of Public Affairs at the California Department of Food & Agriculture:

“This invasive pest is a threat not only to our nursery growers and date palm farmers,” said California Department of Food and Agriculture (CDFA) Secretary A.G. Kawamura.  “It also endangers all of the decorative palms that are so common in our landscape and so much a part of the classic California backdrop.  I would like to express my gratitude to the landscape contractor who originally reported this pest. He is a Good Samaritan who did the right thing when he took the time to notify local agricultural authorities, and he has given us a very valuable head-start in our efforts.”
 
In response to the original contact by the landscaper, state and local agricultural officials, working in partnership with the USDA, began an extensive, door-to-door survey in the neighborhood and are setting about 250 traps to determine if an infestation exists.  Protocols for this pest call for an initial survey covering a 1.5 square mile radius around the detection property, resulting in a trapping array covering nine square miles.
 
The red palm weevil, scientific name Rhynchophorus ferrugineus, is a major pest of palm trees, many of which are highly valued as landscaping plants, generating approximately $70 million in nursery plant sales in California annually. Palm trees are also used for producing crops and marketable agricultural commodities including coconuts, dates and oils.  In California, date palm growers harvest an annual crop worth approximately $30 million.  The vast majority of these farms are in the Coachella Valley region.  
 
The red palm weevil is native to Southeast Asia and has spread throughout the Arabian Gulf.  It is found in parts of Asia, Africa, the Middle East, Europe and Oceania.  Prior to the detection in Orange County, the closest confirmed infestation to the United States was in the Dutch Antilles in 2009, the first report of the pest in the western hemisphere.  It was also confirmed in Aruba in 2009.
 
Female red palm weevils bore into a palm tree to form a hole into which they lay eggs.  Each female may lay an average of 250 eggs, which take about three days to hatch.  Larvae emerge and tunnel toward the interior of the tree, inhibiting the tree’s ability to transport water and nutrients upward to the crown. After about two months of feeding, larvae pupate inside the tree for an average of three weeks before the reddish-brown adults emerge. Adults live for two to three months, during which time they feed on palms, mate multiple times and lay eggs.
 
Adult weevils are considered strong fliers, venturing more than a half-mile in search of host trees.  With repeated flights over three to five days, weevils are reportedly capable of traveling nearly four-and-a-half miles from their hatch site.  They are attracted to dying or damaged palms, but can also attack undamaged host trees.  Symptoms of the weevil and the larval entry holes are often difficult to detect because the entry sites can be covered with offshoots and tree fibers.  Careful inspection of infested palms may show holes in the crown or trunk, possibly along with oozing brown liquid and chewed fibers.  In heavily infested trees, fallen pupal cases and dead adult weevils may be found around the base of the tree.
 
Residents are encouraged to report suspect infestations by calling the CDFA Pest Hotline at 1-800-491-1899.

 

CDFA Protects!

By Johanna Silver, Sunset test garden coordinator

The roses in the test garden are still blooming like crazy.

But if you look a little closer, you can see that I have the most common foliage problems.

I have rust:

• I try to keep a tidy rose bed. I pick up dead leaves off of the ground. I also pluck diseased ones off of plants as I catch them.

• I water with a soaker hose to keep the leaves as dry as possible. Fungi and bacteria love moisture.

• I plant disease-resistant varieties, and I remove rose bushes that are particularly badly diseased.

• I don't worry. Look, foliar flaws happen this time of year. Can you live with it? I definitely can. If not, consider planting something else, rather than getting the chemicals out.

Here is Sunset's advice for growing the perfect rose.

And here are some basic tips on rose care. 

And lastly, a few more tips on what to do when things go wrong.