Saturday, March 12, 2011

Chickening out on vinca

Last weekend’s gardening chores included planting a variegated periwinkle (Vinca minor ‘Illumination’) in the ground near a clumping bamboo (Borinda papyrifera). The idea was to let the vinca fill in the bare spots near the bamboo. Even when not in bloom this is a beautiful groundcover, and I was excited to have found it.

Vinca minor ‘Illumination’

However, several readers expressed concern about vinca’s aggressive growth so I decided to do some research to confirm that I had made the right decision. I didn’t take long before I realized that I probably had not. The Internet is full of horror stories about vinca. Apparently it has the ability to engulf and smother everything in its path. Since it competes aggressively for water and nutrients, it simply starves other plants that might get in its way.

While I do take what I read online with a grain salt, enough doubt was raised in my mind that I decided to dig up my Vinca minor ‘Illumination’ and instead put it in a bowl in the same location. Our backyard is simply too small to play Russian roulette.

Vinca minor ‘Illumination’ in the ground…
…but now confined to a clay bowl with a piece of plastic underneath to prevent roots growing through the drain holes into the ground

Interesting bits and pieces of information I unearthed about vinca:

Vinca minor is classified as invasive in CA, CT, DC, DE, GA, IA, IL, IN, KY, MD, MI, NC, NJ, NY, OH, OR, PA, RI, SC, TN, TX, VA, WA, WI, and WV.

The U.S. Forest Service featured Vinca minor as its Weed of the Week on 2/1/2006. I love the “Weed of the Week” designation. Why should the pretties get all the attention?

Vinca is native to Europe and was introduced to the U.S. in the 1700s as an ornamental.

During the Middle Ages, criminals wore wreaths made of vinca on their way to their place of execution.

In Italy it was called Flore de morte (flower-of-death) and placed on the bodies of dead infants.

The Book of Secrets of Albertus Magnus: Of the Virtues of Herbs, Stones, and Certain Beasts describes a very special use for vinca:

When wrapped with earthworms, then beaten into a powder and cooked with an herb called houseleek [succulents we now call “sempervivum”], periwinkle will induce love between man and wife if they partake of it as part of their meals.

And there you have it. More than you ever wanted to know about vinca a.k.a. periwinkle, creeping myrtle, joy-on-the-ground, flower-of-death, blue buttons, hundred-eyes, devil’s eye, or sorcerer’s violet.

Friday, March 11, 2011

Of cannas, dogs, and dryer sheets

A few weeks ago, I blogged about starting cannas from seed. I ended up with four small (2-inch) pots, each containing one seed of banana canna (Canna musifolia). I placed the pots on the sill of our dining room window, which goes almost all the way to the floor. This window gets morning sun and good light most of the day. The pots were in plastic bags to create a warmer and more humid environment. So far so good.

Banana canna (Canna musifolia)
Image source:

A couple of weeks later, we had dinner with friends and when we returned we were greeted by a nasty mess: pots and soil all over the floor, the plastic bags shredded into pieces. Apparently our black lab, forever obsessed with food, thought there might be something tasty inside those plastic bags, which were at a perfect height for her to reach. I’ll spare you my reaction, but in hindsight I do laugh about it—and I have no one to blame but myself. I’ve definitely learned my lesson: Never underestimate a Labrador retriever’s curiosity and always keep things that matter out of her reach!

Only one of the four seeds (just starting to germinate) survived the mauling, and I was extra determined to make it thrive. I’ve had problems in the past with seedlings dying, either from damping off, which is typically caused by a fungus, or from the larvae of fungus gnats which eat the tender roots of seedlings. Fungus gnats are small insects (about ⅛ inch in length) you often see buzzing around plants. They lay their eggs in cracks on the soil surface, and within a week, the larva begin to feast on roots.

There are several remedies to deal with fungus gnats (see here and here, for example). However, I recently read about a solution that promises to be not only quite effective, but also wonderfully fragrant. called it a “modern old-wives tale”: Bounce® dryer sheets keep mosquitoes and gnats away. True or false? Now we know, at least as far as gnats are concerned. Kansas State University Department of Entomology professor Raymond Cloyd and colleagues conducted experiments to test whether Bounce® dryer sheets from Procter and Gamble (specifically Outdoor Fresh Scent™) repel adult fungus gnats. Their finding: Yes, they do, at least under laboratory conditions. To get all the details, read this summary by the American Society for Horticultural Science. The complete study can be found here.

Figuring I have nothing to lose, I decided to place a dryer sheet—fresh out of the box, not previously used—on top of my lone Canna musifolia pot. I cut a hole where the seedling had begun to emerge from the soil and put a small rock on top of the sheet to hold it down. If all goes well, no fungus gnat will go near it to lay their eggs. Of course I have no way of knowing whether there were eggs in the soil already, but I haven’t seen any gnats flying about lately.

Dryer sheet on top of 2-inch pot, held down by a small rock

This certainly isn’t a scientific experiment, just something to give me peace of mind considering this is the only Canna musifolia I have left. But assuming you start with clean (sterile) potting medium, just placing a dryer sheet or two near your seed trays—not even necessarily on them—might be enough to keep gnats away.

One major question is still unsolved though: Is Bounce the only brand that works? Because I must admit that our dryer sheets are Costco’s Kirkland brand.

Thursday, March 10, 2011

Cactus rescued from the gutter

Our town has curbside yard waste pickup, which essentially means that you can put anything compostable out by the curb and the city will pick it up once a week. Walking around town, you can find all kinds of things of interest to a gardener. Some people even advertise plants they’re tossing out on, a “network to promote waste reduction and help save landscape from being taken over by landfills.” 

Yesterday, as she was walking the dog, my wife came across a bunch of cactus segments lying in the street a few blocks from our house. Knowing that I would probably not be able to say no to such a find, she called me to ask if I was interested. I actually knew which house (and cactus) she was referring to, so I said sure. My wife, bless her heart, then proceeded to lug home a 40 inch segment, wrapped in a plastic poop bag she had on her. Luckily, the segment wasn’t very spiny—nothing like a prickly pear or cholla—so she didn’t sustain any physical harm.

I went back later in the day to get three more segments, ranging in length from 20 to 50 inches, because I didn’t want them to end up in the community compost pile. I ended up talking to the homeowner who told me that with all the rain we’ve been having her cactus (now 20 years old and mature) was growing more vigorously than she liked so she had been removing segments to keep it in check. I think she was amused by my rescue endeavors and added that every time she puts cactus pieces by the curb they tend to disappear quickly. It sure sounds like other cactus aficionados in town are keeping an eye on yard waste piles!

Image source: Wikipedia

The cactus these segments came from is a Cereus hildmannianus, technically subspecies hildmannianus (a big thank you to Xenomorf in the Cacti and Succulents forum on Dave’s Garden for the correct ID). Its common name is “Queen of the Night” because its blossoms open at night. Check out this beautiful photo of a specimen in bloom.

This Argentinian and Brazilian native has the potential to grow to 30 feet and can form a large clump. The plant my segments came from is about 15 feet tall and actually looks perfectly proportioned in front of a single-story home with Mexican architecture. I’ve found conflicting information about its cold-hardiness but it definitely does well in our zone 9b so I’d say it’s hardy to at least 25°F.

Cereus hildmannianus_02
The 40-inch segment my wife brought home
Cereus hildmannianus_06
The three other segments I got later in the the day

Cereus cuttings root very easily—in fact, I could have cut each of these segments into 12 inch chunks, and if the literature is correct, they would have rooted. However, before placing them in soil, it is crucial that the cut be completely healed (callused over). Otherwise you run the risk of infection and rot, especially if the soil is damp.

My segments aren’t cuttings per se. Instead, they are “arms” of the mother plant that were simply twisted off. Since the wounds have a very small surface area, they were dry by the time I brought home my finds. However, one segment had a fairly jagged tear so I decided to make a cleaner cut. I don’t think this was really necessary but I prefer to err on the side of caution in these things. I left the other three segments as is, i.e. I didn’t re-cut the wounds.

Cereus hildmannianus_01
Jagged wound that resulted from twisting the segment
off the mother plant
Cereus hildmannianus_05
Before making the cut, I sterilized the knife with 70% isopropyl alcohol
Cereus hildmannianus_04
After making the cut, I poured 70% isopropyl alcohol over it to kill any microorganisms and to dry out the tissue

The next step is to leave these segments in a protected place in the shade for a couple of weeks so a protective callus can form over the wounds. After that I will place them in pots with dry cactus mix, supported by sturdy stakes. Watering won’t be necessary (in fact, would be detrimental) until roots have begun to form. This could take anywhere from a few weeks to a few months, depending on the temperature. I’ll post updates as things happen.

The moral of this story is to keep an eye on what your neighbors toss out. Their yard waste could be your treasure!

Of course the downside of finding a treasure is figuring out what to do with it. Where am I going to plant these substantial cacti? That is the million dollar question!

Tuesday, March 8, 2011

Spring in Napa Valley

Napa Valley is only an hour’s drive from here, but it might as well be 500 or 1,000 miles away considering how often we go. However, every time we visit I fall in love with it all over again. It is a stunningly picturesque valley, running north to south, surrounded on the western and northern sides by the Mayacamas Mountains and on the eastern side by the Vaca Mountains. The climate is Mediterranean and obviously as perfect as it gets for growing grapes since Napa Valley is one of the premier wine-making regions in the world.


In early spring, the vineyards explode in a riot of green and yellow. The yellow is from wild mustard (Brassica juncea). History—or is it rumor?—has it that Spanish missionaries sowed mustard to mark the trail between their missions in California. It’s a wonderfully romantic story, but it is more likely that mustard was introduced as a cover crop and then just took over because it self-seeds so profusely.


Wild mustard is very popular with vintners because it is so beneficial. It has a deep taproot that breaks up compacted soil and naturally repels nematodes that might otherwise damage grape vine roots. After it has peaked—and done its job of attracting tens of thousands of visitors—it is mowed and plowed under to add nitrogen to the soil.


The photos in this post were taken on the eastern side of the valley along the Silverado Trail. I love the geometric patterns formed by the rows of grape vines in the vineyards, many of them alternating between yellow and green.


Wild mustard can also be found outside of the vineyards, on hillsides and along the road. It truly is the most dominant plant in Napa Valley at this of year—so much so that it inspired the annual Napa Valley Mustard Festival, a popular art, music and wine festival that unfortunately this year has been scaled down because of the economy.


Most of the old orchards that were planted alongside the vineyards are now gone, replaced by more vineyards, which admittedly are much more profitable than any orchard would ever be in Napa Valley. However, occasionally you still see fruit trees erupting in bloom in February. Their blossoms contrast beautifully with the vibrant green and yellow of the vineyards.

On a warm day, the trees are alive with bees
and the occasional hummingbird

Monday, March 7, 2011

UC Davis Arboretum Terrace

The University of California Davis Arboretum truly is a treasure in our small college town. With miles of walking path and 17 different gardens/collections spread out over 100 acres, it’s a resource many UCD students and locals enjoy as part of their daily life.

I’ve blogged about the Arboretum before, most recently about their Valley-Wise Garden. This post isn’t about the actual Arboretum located on the UCD campus, but rather about the Arboretum Terrace, a demonstration garden in downtown right next to the Borders bookstore in the Davis Commons shopping center. This is a great location, smack in the middle of one of our most popular hangouts. In addition to gardeners wanting to learn more about suitable plants to grow in our Mediterranean climate, many people visit the Terrace to read, eat their takeout food from one of the nearby restaurants, or just enjoy some quiet time.

View towards entrance

The Arboretum Terrace is landscaped like a Mediterranean courtyard, with meandering planting beds on either side, tables and chairs for relaxing, shade structures and a water wall at the far end, and large planters showcasing the possibilities of container gardening. Interpretive displays describe the basics of Mediterranean gardening, selecting climate-appropriate plants, and saving water.

Many plants used here are California natives; others come from other parts of the world with a similar climates. I love that this is a real horticultural treasure trove where you’ll find common plants like Spanish lavender and deer grass right next to plants rarely seen in commercial nurseries like Farfugium japonicum 'Argenteum'.

Potted black bamboo (Phyllostachys nigra)

I enjoy coming here, as does my entire family. We often get a smoothie from Jamba Juice or frozen yogurt from Pinkberry and then walk over to the Arboretum Terrace to consume it. The plants are meticulously maintained by a crew of volunteers and most of them are labeled. This allows you to write down your favorites and replicate the look in your own garden.

Even though it was raining today, I decided to see what’s in bloom, and I wasn’t disappointed.

Beautiful vignette. The wall in the background is the Borders bookstore.
Chaparral currant (Ribes malvaceum) in bloom (pink flowers). Unfortunately, the yellow-flowered plant wasn’t labeled, but it is a stunner.
Creeping mahonia (Berberis aquifolium var. repens), small groundcover shrub to 2 feet. You can still see its beautiful fall color; new leaves are glossy green. The flowers are bright yellow. Native to the California mountains from the Klamath Range and the North Coast Range to the Cascades and Sierra Nevada.
Vine hill manzanita (Arctostaphylos densiflora ‘Howard McMinn’), evergreen shrub to 7 feet tall, very showy flowers; originally selected from wild stands in Sonoma County.
California lilac (Ceanothus ‘Ray Hartmann’). ‘Ray Hartmann’ is an erect variety with the potential to grow up to 20 feet tall. Can be trained into a tree. All ceanothus demand perfect drainage and very little to no irrigation in the summer.
Bush germander (Teucrium fruticans ‘Azureum’), small shrub to 5 feet tall. Very tough; grows pretty much anywhere. Reliable bloomer from spring to fall.
Golden currant (Ribes aureum), deciduous shrub to 6 feet. Native to moist areas of the Sierra Nevada but tolerates anything from standing water to drought.
Leopard plant (Farfugium japonicum 'Aureomaculatum’) surrounded by fallen blossoms from Taiwan cherry tree (Prunus campanulata).
Potted aloes—the large ones in the foreground are a hybrid between common soap aloe (Aloe maculata) and coral aloe (Aloe striata)
Spider aloe (Aloe x spinosissima). The Arboretum has a lot of these, both here in the Terrace and on campus. Appears to bloom from a young age.

If you’re ever in Davis, I highly recommend a visit to the Arboretum Terrace. It is located at the corner of 1st and E Street right next to Borders.

Sunday, March 6, 2011

Saturday garden chores

Sometimes you do one big thing in your garden that has an immediate and dramatic impact, like installing a water feature or plopping down a giant rock. But that doesn’t happen all that often. Most of the time it’s many little things that contribute to the overall result. Chores fall in that category. Each one individually may not be much, but it all adds up.

For me, a typical weekend of gardening consists of a variety of seemingly unrelated tasks. Some are dictated by the weather or the season, others are the result of what I feel like doing that day. I often bumble about from one thing to the other, with no aim other than to be outside and have fun in the garden.

Today was a day just like that. I didn’t really know what I wanted  to accomplish when I started out, but at the end of the day I felt satisfied with what I had gotten done.

The first order of business was doing some pruning on our Washington Navel orange tree. It’s a dwarf tree, more than 15 years old now, and we’re trying hard to keep it compact so we can reach the fruit. I removed a couple of larger branches that had begun to creep towards the cordylines (lower left in the following photo) and I picked all the oranges that had fallen. We try to be diligent about picking all the fruit, but some always drops and starts to rot.


I need to do a bit more shaping on the top of the tree, but I do it in baby steps rather than taking off too much at a time.

I then cleaned up the callas that had sustained some damage in January. A few more weeks of warm temperatures, they’ll look perfect.

Callas along the north side of the house.

Just the other day I commented on this Vinca minor ‘Illumination’ starting bloom. I bought it a few weeks ago but hadn’t decided where to put it. I ended up planting it near our Borinda papyrifera, a clumping mountain bamboo with beautiful bluish culms. There are lamium and sweet woodruff in that area already, and I think this vinca will complement them nicely. Some readers have expressed concern about it become invasive, so I’ll keep a close eye on it.

Still lots of room to roam for this Vinca minor ‘Illumination’

On our recent trip to Southern California I saw several purple prickly pears (Opuntia santa-rita) in people’s yards. None of the nurseries we stopped at had them for sale, but luckily I was able to find a source on the Internet, My order arrived just the other day, and I’m very happy with the purple coloring!

The plant was bare root, wrapped in a brown paper bag. In the first photo, you can clearly see the roots sprouting from the bottom and the sides of the pad from which it was propagated. I potted it up using the bag method I described last week, and I’m happy to report I didn’t get pricked by a single glochid.

110305_santa_rita_roots 110305_santa_rita_potted

After reading a few books by Tucson landscape designer and garden writer Scott Calhoun I had been wanting to mulch my succulents with small rocks so I decided to make a quick run to the home improvement store. I picked up two kinds of rocks, one called Southwest Cobble and the other California Gold, and I trial-mulched a few cacti. I must say I like the results.

Purple prickly pear (Opuntia santa-rita) with California Gold
Golden barrel cactus (Echinocactus grusonii) with Southwest Cobble

I then remembered then I had collected some rocks on our Southern California trip (something I do on most trips) and placed a few in the succulent bowls I planted last month. Something was missing in some of them, and I think the rocks did the trick.


I can’t wait for the rainy season to end so I can uncover my succulent table and properly display my budding collection of prickly plants!

Saturday, March 5, 2011

Interactive plant hardiness zone map

I’m sure that you, as an avid gardener, know your plant hardiness zone. There are many websites that display your zone after you enter your zip code. Some may only give full zones, others may indicate subzones as well (e.g. 9b, my zone).

However, I just came across a site that beats all other hands down. It’s called, and it displays zone information for the USA, Canada, and the UK. What makes it so great is its ease of use and the way information is displayed. Using Google Maps technology, it lets you drill down as far as you like, even to street level, although that’s not very useful in this case.

For example, selecting the map for my home state of California I get this:


Using the zone boxes along the left and the top, I can display and hide zones as desired.

Entering my zip code results in a map with weather statistics:


After I close the weather statistics, I see a map of my region with the zone overlay. I can then zoom in or out to see if I live close to a lower or higher zone.

For example, when I zoom out a couple of levels, I see that we’re surrounded by many different zones ranging from 7a to 10a. (In the following screenshot, the distance from the top of the map to the bottom is roughly 100 miles.)


While I knew that San Francisco and Marin County were zone 10a, I had no idea that there was a small enclave of zone 10a northeast of Sacramento. It even encompasses parts of Woodland, our county seat, located about 10 miles to the north. I really can’t explain why it’s warmer there than here; it might be because of the moderating influence of the Sacramento River. I must admit that I have a bit of zone envy; I’d love to have the extra few degrees of protection zone 10a would give me :-).


If this site sounds interesting to you, check it out yourself at

Friday, March 4, 2011

Australia, what have you been smoking?

Last week, I read that in an effort to curb illegal drugs the Australian government wants to ban thousands of plants that contain either mescaline or dimethyltryptamine (DMT), a naturally-occurring hallucinogen that is ubiquitous in nature. At first glance this sounds like a good thing, considering that the government is supposed to look out for the welfare of the people. However, at closer examination, I was at first amused, then startled and finally p**** off to discover that this looks like government interference—or should I say arrogance?—taken to a whole new level.

Golden wattle (Acacia pycnantha), Australia’s state flower,
about to become illegal?

The Australian government plans to prohibit all plants that have even the tiniest amounts of these substances, never mind that (a) neither DMT nor mescaline play a role in the illegal drug trade, and (b) most of the plants on the list contain only such tiny amounts that it would be virtually impossible to extract enough for drug use. The list of plans to be banned is so extensive that virtually every nursery and gardener in Australia would be affected. The following would be prohibited:

  • All brugmansia and datura species—no more angel’s (or devil’s) trumpets down under!
  • Angel’s trumpets soon to fall silent?
  • All cacti species that contain even tiny trace amounts of mescaline—no more prickly pears for you, or saguaros, or mammillarias (the largest cactus genus), or hundreds of other popular cacti.
    Prickly pear to land you in jail?
    As if getting glochids in your skin wasn’t bad enough!
  • No more wattles and wattle-relatives—this includes not only Australia’s state flower, the golden wattle (Acacia pycnantha), and other acacias, but also many plants we’re familiar with in the U.S., such as delosperma (a very popular ice plant—I have several in my front yard), giant reed (Arundo dondax), and all wisterias—yes, wisterias! I bet you didn’t know you could get high off of wisteria!
No more wisterias for desperate housewives?

And the list goes on.

This website has a wealth of information on the proposed legislation and its disastrous effects on gardening in Australia. This article has a more humorous take. And this article quotes a prominent biodiversity advocate, Robyn Francis, who says:

“It’s just crazy. One of the species on the list is a common agricultural weed – is every farmer who has that growing on their land liable to be imprisoned because they’re growing ‘commercial quantities’?

“And what about all our local wattles [acacias], which just grow up by themselves as pioneer species – it means ecology suicide to enforce things like this and it’s unrealistic.”

Since I’m not an Australian citizen, I can’t really do anything about this, but if you reside in Australia, I urge you to let Brendan O’Connor, the Minister of Justice, know what you think. Garden Freedom has a handy contact form.

It’s easy to laugh at this, but don’t think for a second our own government—Democratic or Republican—isn’t capable of going down a similar path.

Image source: All images from Wikipedia.

Thursday, March 3, 2011

Bamboo sighting around town

No matter where I go, I’m always on the lookout for interesting plants—especially bamboos, succulents, and large-leafed tropicals plants because these happen to be my favorites.

While bamboo is still fighting an uphill battle for acceptance in the U.S., I’m glad to see that even in our town of 60,000 more and more businesses and private individuals are embracing it for its unique beauty and landscaping potential.

I recently came across this beautiful arrangement of Phyllostachys aurea ‘Holochrysa’, the truly golden form of “golden bamboo”. While the plants are still relatively juvenile—maybe 6 ft in height—they already have the unique compressed internodes that Phyllostachys aurea is known for. In non-technical language, these are the relatively short sections on the canes (culms) between the rings (nodes). You can see them well in the last photo in this post.

Beautiful bamboos in attractive containers

“Golden bamboo” (the species form of Phyllostachys aurea) is actually a misnomer. Its culms are typically all green, and only older culms take on a slight yellowish hue. On the other hand, the ‘Holochrysa’ variety in these photos is truly golden, and a beautiful burnished golden color to boot.

I love how the elegant look of these bamboos softens the hardscape outside this office building

Phyllostachys aurea is a running bamboo. Unless you have a large property and don’t mind if it spreads, it shouldn’t be planted in the ground without some form of containment (like a rhizome barrier) or a regular regimen of rhizome pruning. In this case it doesn’t matter because the plants are in metal containers. I absolutely love the look of these simple metal containers, but since they’re relatively shallow, the plants will have to be divided, thinned and/or root-pruned every couple of years to ensure their long-term health.

Close-up of culms with compressed internodes

I can’t repeat myself often enough: I’m thrilled to see that businesses around town are using bamboo for landscaping, and I hope the trend will continue. I will do my part to spread the word.