first published July 22, 2010

Typically, flower children and guerillas have little in common. But traits of both earth-loving spirits and radicals are definitely evident in a new hybrid—guerilla gardeners. Their approach is a trend that’s taking root (pardon the pun) in urban areas. Guerilla gardeners transform bleak-looking areas in cities by anonymously planting seeds, perennials or shrubs. The catch is they’re using someone else’s land without permission.

In its simplest form, guerilla gardening is about planting a few annuals in a neglected public planter or on the bare ground beneath a tree. On a larger scale, it can escalate to commandeering long-vacant lots. From what I can determine, guerilla gardeners believe that bare patches of soil are eyesores in desperate need of makeovers or, more drastically, that they’re affronts to nature and humanity. Certainly, Mother Nature abhors barren swatches of fertile ground and does her best to fill them in. So, from that perspective, guerilla gardeners are simply acolytes speeding up the natural process by putting their personal green signatures on the ground.

However, whether their purpose is to naturalize, beautify, improve biodiversity or provide food security, what they’re doing is technically illegal. So, guerilla gardening is sometimes done under the cover of night or by employing creative strategies to avoid trespassing, one of which is a technique called seed bombing. How it works is seeds along with compost mixed with clay are packed into a biodegradable, tennis ball-sized “shell.” The ammo is then tossed into a desolate plot where it serves as a great bunker from which the seeds can grow and become anchored in the soil. Another interesting, albeit dangerous, practice I’ve heard about is to fill street potholes with soil and seeds or transplants. Of course, a pothole isn’t the best environment for plants—nor is dodging cars a safe practice.

While the two examples I’ve given are rather radical, the majority of guerilla gardening activities are a lot more conventional. In fact, many guerilla gardeners are inspired simply because they can no longer tolerate empty flower containers or tree wells filled with cigarette butts and trash. Let’s face it, regularly walking past an eyesore can wear on one’s spirit. Fortunately, even a few flowers can have a remarkably positive affect on one’s outlook. However, before you decide to become a gardening guerilla, keep in mind that random planting of anything on municipal property is against the bylaws in most cities. And it’s not always practical either. Even though grass on city boulevards may look boring, it’s easier for maintenance crews to mow around trees and prune when there aren’t ornamentals planted around the tree bases.

Of course, you also need to remember that trees don’t like plants and soil pushed right up against their trunks. So, while the thought is in the right place, you might instead want to participate in programs, such as Partners in Parks, where municipal officials are more than happy to partner with would-be-guerillas.

So, am I advocating the spread of guerilla gardening in cities and towns? Well, I like the altruistic philosophy of guerilla gardening but shy away from some of the approaches, which could get you in trouble. However, every time my car hits a crater in the road, I can’t help but think how some plant-inspired pothole fixes would save my suspension.

Sightlines at the Enjoy Centre continue to evolve. Third floor offices on the south and north of the retail greenhouse are connected by a catwalk This week, the catwalk could be accessed, giving new views looking west and looking east. Meanwhile beams for the roof of the cafe kitchen were also put in place this week.

Hits & Misses: Faithful seeds & spotty damage
Question of the Week: Why are my tomatoes cracking?
Science & Technology: Space bound spruce

Cherry Festival was on last weekend and there I was enjoying myself in…Bruno, Saskatchewan. Where the heck is Bruno and what does it have to do with cherries you ask? Well, the town is a little over an hour east of Saskatoon, and the province is known for its expertise on sour cherries for the Prairies. Specifically, a tremendous amount of research has been done by Dr. Bob Bors, a fruit specialist at the University of Saskatchewan. A direct result of that research is a number of excellent, cold-hardy cherry varieties that have spawned a growing industry in Saskatchewan, as well as Alberta and Manitoba. Officially, I was at the festival as a guest speaker. But as a festival attendee, I also got to sample products including dried sour cherries—their flavour was outstanding. However, the best thing I tasted was the chocolate-covered sour cherries. The tartness of the fruit combined with the exquisite chocolate was out of this world. I’ll never touch another maraschino-style chocolate again…Bruno has spoiled me!

‘Carmine Jewel’ is one sour cherry that was developed in Saskatchewan.

Hits & Misses
Hit: Faithful Seeds
While I was in Bruno, a fellow named Noel LaBrash handed me a dozen seeds from a legendary local tomato. I’m told the unnamed tomato produces huge yields of large yellow tomatoes that are somewhat pear shaped. Apparently, it’s been grown in the Bruno area for over a hundred years and local historians attribute the original plants to a Catholic nun, who handed down the seeds year after year. Noel has taken it upon himself to ensure these outstanding tomatoes carry on by giving seeds to people who are interested. I’m just lucky to be one of the recipients!

Miss: Spotty Damage
Leaf spot on trees seem to be everywhere this year. It appears when pathogenic fungi and bacteria attack foliage resulting in black or brown marks. These spots and blotches often show up shortly after periods of wet weather—something we’ve had an abundance of this year. Provided trees and shrubs are healthy and well maintained, most leaf spot is just an aesthetically displeasing nuisance. That said, dormant season sprays (lime and sulphur combinations or horticultural oil) can help reduce some of the fungi and bacteria that overwinter on bark and twigs.

Question of the Week
Why are my tomatoes cracking?
The cracks on the top of tomatoes are caused by very rapid growth, often during a warm rainy period preceded by dry or much cooler weather. Basically, during rapid growth the pressure inside the tomatoes splits the skins. Cracks most often happen when fruit is full-sized and beginning to ripen. Obviously, you can’t control the weather, but keeping your tomato plants as consistently moist as possible will help prevent splitting.

Science & Technology
Space Bound Spruce
Dr. Jean Beaulieu a researcher in Quebec has been working with NASA, and other partners, to test the affects of zero gravity on white spruce. This winter some room on the space station will be allotted to Dr. Beaulieu’s trees so that researchers can examine how weightlessness changes spruce growth at the cellular level.

Did You Know?
There are close to 50 bumblebee species native to North America, while honeybees are non-natives introduced from Europe.

“In the long run the pessimist may be proved right, but the optimist has a better time on the trip. ”
–Daniel L. Reardon

I can’t avoid thinking about tracks this week. Partly because we’ve been busy preparing and delivering planters and floral arrangements to the racetrack for the Indy in Edmonton this weekend. But also because, at the Enjoy Centre, tracks were being put in place for the travelator. Work on the inclined walkway, which will accommodate shopping carts and allow customers to move easily between the lower and upper levels, started yesterday. As planned, the lower-level cement floor had been poured in anticipation of the installers arriving from the USA. The crew will also be installing an elevator for the Enjoy Centre while they’re here. Obviously, the upward and downward travelator tracks won’t reach any great speeds, but I’m still looking forward to test-driving it.

Hits & Misses: Fungi cropping & deer grazing
Question of the Week: How short should my grass be cut?
Science & Technology: Blooming-good reasons for plants

I’ve just returned from a speaking tour that began in Lethbridge, moved on to Cranbrook and concluded in Kelowna. There were no hitches at the first two engagements, but on the way to Kelowna things went a bit sideways. One highway was closed for four hours because of a head-on collision; another was closed because of a fire. To get to Kelowna, our (yes, this road trip included my family) only choice was to take the detour route, a nine-hour drive that meant we’d barely make it in time for my presentation. Fortunately, we arrived with a half hour to spare, which gave me a few minutes to find a washroom and change my clothes. The Kelowna audience was great, the DVDs kept the kids happy in the car and I don’t think I looked too disheveled at the podium.

Hits & Misses
Hit: Fungi Cropping
With the recent rain, mushrooms are popping up everywhere. The first inclination of many people is to destroy them. Not me. I see them as wonderful, intriguing species in their own right. The diversity of the fruiting bodies (the spore bearing structures of fungi) is amazing. Yes, some, such as the fairy ring fungi, can be rather annoying, although most other species aren’t as intrusive. Some are beneficial organisms (aka mycorrhizal fungi) that associate with tree root systems and help the plants extract nutrients and water from the soil. But if you’re still not sold on mushrooms, remember they’re short-lived and will soon disappear.

Miss: Deer Grazing
Regardless of which community I speak in, whenever I ask if there’s a deer problem, the facial expressions of the audience are strangely similar to those of my tween daughter when I ask her…well, when I ask her pretty much anything. You know, the duh-what-do you-think look. Deer have voracious appetites and there’s a much larger list of what they will eat then what they won’t eat. This week, the latest victims in one garden were tomatoes. The deer not only ate the fruits, but the leaves and stems were consumed with equal zeal. Tomatoes are in the deadly nightshade (Solanaceae) family and, while the leaves aren’t acutely toxic I wouldn’t have thought they were that palatable, even to deer. At the very least, there must be a few deer wandering around with upset stomachs.

Deer decimated this heirloom tomato plant.

Question of the Week
How short should my grass be cut?
When grass is growing fast, there’s certainly a temptation to cut it very short so that you don’t have to mow so frequently. But that’s not the best thing for your lawn. Ideally, the mowing height should be 6–7.5 cm (2.5–3”). During hot, dry periods raise your mower blade and cut a centimeter or two higher than usual. Taller grass provides shade for roots and helps hold water in the soil. In addition, when it’s longer, not-so-lush grass also looks richer.

Science & Technology
Blooming-good Reasons for Plants
A world without angiosperms (all plants that bloom) would also be a lot hotter and drier, says an article in Science. Researchers from the University of Chicago used climate models to show the probable outcomes. Results suggest the biggest impact would be in South America where annual rainfall would drop by 30 cm. In the wettest rainforests, precipitation would decrease by as much as 80 percent. Now that’s another good reason to support plant conservation.

Did You Know?
Grey mold (Botrytis cineria) is detrimental to many plants, however, it also plays a beneficial role in winemaking where it takes on another name—Noble Rot. When Noble Rot attacks grapes, it causes the fruit to dehydrate, thereby concentrating the sugars. The mold also releases compounds that add to the grapes’ flavour.

“If everything seems under control, you’re just not going fast enough.”
–
Mario Andretti

T

Jim is away on a working holiday, which has included speaking to gardeners in Lethbridge, Cranbrook and Kelowna, so the Notebook is on hiatus this week. Other than having to detour around a fire in B.C., Jim says it’s been a good trip. He’ll have more details to share next week. Meanwhile, here are some images from the greenhouse. Enjoy!

first published July 9, 2010

Toughness and reliability are attributes we all want in our ornamental plants. The problem is these bulletproof qualities can also relegate plants—even the most beautiful ones—into the noxious weed category. That’s what’s happened to some stalwart ornamentals last month when they were recently reclassified under Alberta’s new weed control act. And Alberta isn’t the only province updating rules; Saskatchewan will enact a new law this fall. So what does this all mean for you? Well for gardeners it means knowing what plants you may need to remove from your property—and more importantly—why you should care about removing them.

The 46 prohibited noxious weed species on Alberta’s list have adapted so well to our prairie environment that they’ve managed to out compete many native species. When these weeds outperform native species, the food and habitat available for wildlife is reduced. In addition, when noxious weeds invade agricultural lands, they reduce crop yields and quality. That’s why prohibited weeds that have taken up residence here—either inadvertently or intentionally—must be destroyed. In addition to the 46 weeds in the prohibited class, another 29 offenders have the lesser designation of noxious. Even though noxious weeds don’t have to be destroyed, it’s advisable to eliminate them because you are required to control these plants. As an example, creeping bellflower (Campanula rapunculoides) isn’t banned but shouldn’t be allowed to spread beyond your property line —a near impossibility—so really shouldn’t be planted.

As for the prohibited species, most (such as mouse-ear hawkweed or spotted knapweed) have little ornamental value and aren’t usually grown on purpose. But there are a handful of prohibited noxious weeds that are still being actively chosen for their beauty.

One new example on the prohibited list is Himalayan balsam (Impatiens grandulifera), which is a fierce self-seeder. It’s a tall (90–120 cm) annual with purplish lance-shaped leaves and small pink flowers. Also banned is the tamarisk (Tamarix chinensis), a shrub with fine foliage and pretty strings of pink flowers. It has a nasty habit of invading riparian zones and choking out native species. The common name, salt cedar, alludes to the fact it draws salts out of the soil and into its leaves. Unfortunately, when the leaves drop in the fall, the salt leaches into the soil and, over several years, contaminates the soil making it impossible for other species to grow in the highly saline environment.

Tamarix chinensis

In Alberta, it’s mandatory to remove prohibited noxious weeds, meaning the onus is on us to know what’s on the list. (It’s probably not a bad idea for Saskatchewan residents to be proactive and avoid planting the blacklisted plants.) So, to reduce the odds of officials showing up on your doorstep with shovels and garbage bags, you need to become familiar with the plants.

The best way to start is to download the complete list from Alberta Agriculture. If you don’t recognize the plants by name, take suspect samples to local garden centres for identification. The Invasive Plants Council is also an excellent resource to help identify problem weeds and the council’s website suggests alternative species for your garden. Purple gas plants (Dictamnus albus v. purpurea), for example, can sub for Himalayan balsams, and dwarf Korean lilacs (Syringa meyeri ‘Palibin’) are wonderful alternatives to tamarisks.

If you still find yourself wondering if you’re growing a noxious weed or a beautiful ornamental, just remember this simple test: reach over and pull on the plant. If it is impossible to uproot, it’s a weed. If it comes out of the ground really easily…well, it’s probably a rare and expensive ornamental.

Work continues on the third floor office space of the Enjoy Centre where the glue-laminate wooden beams are in place, and the roof is nearing completion.

On Wednesday, the cement floor for the north offices was also poured. Girders for the catwalk that will link the north offices to the accounting offices were also put in place last week.

Meanwhile, on the lower level, refrigeration lines were run under what will be the cement floor. The lines for coolers and freezers, to be used by the bakery and food store, will run inside larger pipes. In case of leaks, junction boxes with built-in drains will act as service points for the lines.

Hits & Misses: Smooth waters & low light
Question of the Week: How do I keep my container garden looking its best?
Science & technology: City improvements

My Canada Day included a family bike ride to Fort Edmonton Park where we enjoyed travelling back in time. The park offers great opportunities to see what life was like in Canada from the 1800s through to the early 1900s. Throughout the park, actors dressed in period pieces greeted us with “Happy Dominion Day” and gave faux looks of bewilderment to visitors who responded with “Happy Canada Day.” That’s because (for those of you who don’t remember) it wasn’t until 1982 that Canada Day became the official name of Canada’s birthday. Thinking I was pretty clever, I tried to see if I could get the volunteers to break out of character, but their acts were pretty darned polished. Almost makes me suspect they’ve heard from visitors like me before…

Hits & Misses
Hit: Smooth Waters
I’ve been enjoying the Coandă effect recently. What am I talking about, you ask? Well, I’ll spare you the long, complex mathematical formula and just say it explains why water clings and flows around solid surfaces in a smooth pattern. From the vantage point of my office window, I can see a water feature that includes a waterspout above a round stone. As the water flows from the spout, it clings beautifully to the stone causing it to look like a gigantic polished marble. It’s soothing and tranquil, but the Coandă effect is not particularly conducive to getting my work done.

Miss: Low Light
Each year, we grow hundreds of petunia barrels for the City of Edmonton and the City of St. Albert. The petunias’ growth has exploded in the past week, and dozens of flowers are now adorning the foliage. I did, however, notice four pots in downtown Edmonton with nary a flower. The reason is simple: the plants aren’t receiving any direct sunlight. They were all tucked close to the entrance on the north side of a hotel. The objective of the placement was obviously to add colour and fragrance as customers entered the premises. Unfortunately, under low-light conditions, petunia growth becomes soft and lanky, and they won’t flower. To solve the problem, the petunias either need to be moved a few metres away from the entrance or replaced with foliage plants that can tolerate low light. In this case, plant needs and human desires simply aren’t compatible.

Question of the Week
How do I keep my container garden looking its best?
Follow these simple steps and you’ll be rewarded with great-looking containers all season long.

1. Water often and thoroughly—until the water pours out the drainage holes.
2. Remember to remove the finished flowers (a.k.a deadheading) to promote repeat blooming.
3. Fertilize regularly. That’s because the large number of plants in a relatively small space soon use up the original soil nutrients. So, add a generous pinch of 20–20–20 fertilizer to your watering can each time you water.

For a visual review of these tips, see our container care video.

Science & Technology
City Improvements
Urban trees and humans are often on a collision course. Disease or a lack of rainfall is often cited when street trees slowly die. But the real reason has more to do with the soil quality and volume than any other conditions. Soil beneath city streets and boulevards is almost always compacted so that the concrete or asphalt above doesn’t crack or slump. But that’s horrible for root growth. As a result, trees grown in compacted soils often die prematurely. To alleviate the problem, researchers at Cornell University have been working on a structured soil that consists of fairly coarse rock, some clay and a hydrogel (a product that holds water and has the consistency of gelatin). Designed especially for urban environments, it’s strong enough to support pavement yet porous enough to allow for excellent root growth. I believe the City of Edmonton is testing structured soils at a couple of sites. I don’t think the results will be disappointing. My feeling is that structured soil will greatly improve our urban tree quality and dramatically reduce tree replacement costs.

Did You Know?
Soil scientists say there are more species of organisms in a scoop of soil than there are above ground in the entire Amazon rain forest.

“In the long run the pessimist may be proved right, but the optimist has a better time on the trip.”
–Daniel L. Reardon

first published June 24, 2010

If you want your newly planted shade tree to have a long healthy life, the first thing you have to do is show a little flare—trunk flare to be accurate. What am I talking about? Well, on a tree, the flare is the transitional zone between the trunk and the roots. On a young tree it’s barely noticeable, but as a tree ages it’s flare becomes more pronounced and takes on a bell shape. They’re a visual reminder of the presence of strong buttress roots radiating out into the soil and anchoring the tree. Now you may think learning about flares will only support your Trivial Pursuit prowess, but they are a visual reminder of a tree’s health and can be the difference between having a vibrant tree, and one that succumbs to a premature death. Here’s what you need to know.

When planting a new tree, make sure the flare is never buried in the soil. This might not seem like a big deal, especially but if you look at how trees grow naturally, once seedlings emerge from the soil they rarely experience a change in soil depth. That cue from Mother Nature is one we need to follow. Trunks and flares are specialized structures designed to live above ground.

So, while roots can handle the rigors of moist soil, trunks and flares can’t. If a flare is buried, it will face a continuous barrage from soil micro-organisms that will introduce rot or other disease that will damage the tree, at best, and kill it, at worst.

If the organisms don’t destroy it first, the other potential scenario is that the tree will self-destruct. That’s because a tree with a buried flare can develop girdling roots whereby roots just a few centimeters below the soil surface can grow to encircle a trunk. As these roots enlarge, they can literally strangle a tree trunk. An example I’ve seen was an improperly transplanted linden tree that had grown t a beautiful 4 m tall before declining and eventually dying after six years. When the tree was dug out, there was one large girdling root—like an anaconda wrapped around its prey.

To prevent either outcome, always start with a healthy, container-grown specimen that isn’t buried too deeply in the nursery pot. That means being a wise consumer—not shopping merely by price, but also checking the quality of the product. Reputable greenhouses will be able to tell you how the tree was grown, how you should plant it and have a solid guarantee. All the same, before planting it’s always wise to locate the root junction and remove soil, if necessary, to ensure that the junction is at ground level. In fact, planting a few centimeters too high is better than planting too low. Also when you transplant, cut off any roots that encircle the rootball because they could develop into girdling roots.

There’s certainly nothing more frustrating or disappointing then having a beautiful shade tree succumb to a girdling root or trunk rot. However, preventing either from happening is fairly simple. Just keep this tree flare trivia in mind to save yourself time and money, and to avoid serious flare-ups in the future.