Short sightedness of current water restrictions, part 2

In my last post, I described how water restrictions mandating hand watering only can lead to fewer trees and plants, which in turn will cause our temperatures to increase.

At stage 4 of the GVRD water restrictions we will not be able to water any plants using treated drinking water, including vegetable gardens.  http://vancouver.ca/files/cov/water-use-plan.pdf

Again, the short sightedness of this plan is puzzling.  If we must allow our vegetable gardens to wither, the consequence will be buying more imported food.  Imported food requires more expended resources in our environment:  commercial levels of watering;  transportation costs;  possible loss of nutrient value in the food through storage, etc.

Here is a link to an excellent video on how bringing trees to the desert, actually moderates the climate:  https://www.youtube.com/watch?v=K1rKDXuZ8C0.  In the GVRD, we seem to be aiming to do the reverse procedure.

Short sightedness of current water restriction stages, part 1

Here in the Greater Vancouver Regional District (GVRD) we have 4 stages of water restrictions.  Beyond stage 2, we must water all gardens by hand, unless the garden is a commercial flower bed apparently.

Watering by hand is laborious and usually less effective than using a timed sprinkler.  Most of us get tired and bored of standing around with a hose.  The result is shallow watering which leads to shallow roots as the plant's roots have to come towards the surface to seek water.

The missing perspective in the water restrictions is that we need trees and plants to provide shade and to transpire into our environment.  If our gardens are shadier, they need less water.  If we have more vegetation, we will need to water less.

Think about walking down a sidewalk on a hot afternoon, not shaded by large street trees.  Then think about walking down a sidewalk on the same afternoon, under the canopy of large chestnuts or maples.  The difference in temperature is noticeable.  The following article breaks down the effect of vegetation more scientifically:  http://www.forestry.gov.uk/pdf/FCRN012.pdf/$FILE/FCRN012.pdf.

If we stop watering our gardens, we will lose a lot of vegetation, and the temperature will increase.

How to find resilient plants for our changing climate

Here in Vancouver, we are in our second rainless summer month.  This used to seem unusual, except last year we also had a record lack of rain.  Combined with almost no snow over the winter, and we have Stage 2 water restrictions already at the beginning of July.  This means we have to rethink our gardens.

Drought tolerant boulevard plants

Now is the time to look around your neighbourhood for plants thriving without irrigation.  For instance, we installed the boulevard plants shown in the photo about 5 years ago.  This group of plants never gets watered, and is in a south facing position, on a corner, with no shade.  These same plants tolerate our winter deluges of rain.

The plants pictured are Lavandula augustifolia (Lavender), Caryopteris, Physocarpus opulifolius 'Diabolo' (Ninebark--a native plant), and Podocarpus alpine 'Red Tip' (Tasmanian Podocarp).  The order is Lavandula, Caryopteris, Physocarpus, Caryopteris, Podocarpus, Lavandula.

The seriousness of this season's drought

Here in Vancouver, and in many areas of the world, we are experiencing a drought.  Our drinking water reservoirs are dependent on snow melt from the surrounding mountains, and last winter's snow fall was far below average.  This will probably mean stage two or higher irrigation restrictions for gardens this summer in Vancouver.

Last year we also experienced a summer drought in Vancouver.

What does this mean for gardens?  Often the effects of negative situations take a year to show up in large plants, like trees.  The trees appear to be only mildly affected by circumstances initially, but if the detrimental situations persist, trees will be adversely affected.  For instance, I noticed the Chestnut trees lining Renfrew at the PNE grounds are already covered in dead leaves.  Chestnuts suffer as street trees in normal summers, but are not usually covered in dead leaves in June.

Large trees are able to obtain water from the water table with their roots, but when the water table lowers due to drought, the trees lose this resource.

Ironically, large trees and all vegetation reduce temperatures and create moisture in the air through transpiration.  Keeping our plants alive is the best way to reduce drought conditions.

Now is the time to look around your garden and your neighbourhood gardens, to see which plants are performing during this drought.  Pay attention to gardens that are not slavishly irrigated, but ones that are irrigated responsibly, i.e.: if the lawn is lush and dripping wet, this is probably not the home of a responsible irrigator.  What plants still look good?  What plants are looking crispy?  Note if the plants are in the shade or full sun.

Registration now open for the Ecological Landscape Design courses.

Now is the time to register for the Ecological Landscape Design certificate course.  I'll be teaching the course twice again this term:  one course in Burnaby and one in Vancouver.

To register for the Burnaby edition, go to Burnaby Continuing Education's website at http://www.burnabyce.com and register for course #1000 or type ecological under keyword.  In Burnaby, the ELD falls under the Horticulture Programs heading.  The Burnaby edition is on Monday evenings 6:30-9:30, and Saturday afternoons 1:00-4:00, from October 4 to December 1, 2014.

To register for the Vancouver edition, go to Langara College's Continuing Studies webpage at http://www.langara.bc.ca and follow the directions to register.  At Langara, the ELD falls under the Sustainable Communities heading.  The Vancouver edition runs Wednesday evenings 6:30-9:30, and Saturday mornings 9:00-12:00, from October 18 to December 13, 2014.

The Ecological Landscape Design course is a two term certificate course, and the second term starts in January.  During those two terms, we work on two separate design projects, learn about everything imaginable, and have a whole lotta fun!

What constitutes a low maintenance garden?

After:  Updated colourful garden, 2 months after installation

We have never been asked to design a "high maintenance garden" yet;  everyone wants a "low maintenance garden."  So what is a low maintenance garden?

Before:  Original garden with lawn

First, this depends on the maintainers.  Is the homeowner someone who enjoys spending some zen time once a week pushing around a lawnmower?  Or perhaps the homeowner enjoys mindless weeding and deadheading while listening to books on tapes.  Alternately, a hired hand could be the only person ever to set foot in the garden.  These factors need to be considered when designing a garden.

Second, for a garden to be low maintenance, it must be designed for the environment.  Plants are chosen according to soil conditions, the amount of sun available, the drainage patterns, and the traffic patterns in and around the garden.


The garden pictured here is one that has evolved over its 35 years.   The original garden was a developer's special:  Azaleas and Junipers.  The homeowners introduced various favourite plants over the years: sometimes choices were appropriate;  other times not.    Live and learn.  

The children became adults and moved out.  Then came grandchildren, so low maintenance evolved into lawn.  Lawn is easy to cut, and somewhere for the kids to play.  The grandchildren grew up, and the owners could no longer mow the lawn.  Now they were dependent on the kindness of neighbours to keep the entrance welcoming.  So the next evolution was introduced.

The advantage is that now the owners are very familiar with their garden:  the soil conditions, the amount of sun available, the drainage patterns, and the traffic patterns in and around the garden.  With all of this information, and a better sense of plants available, the garden is now a colourful, low maintenance garden.

Plants grow, so plan ahead

Thuja plicata (RedCedar) hedge

This photo portrays an excellent example of a short sighted landscape design.  This RedCedar hedge is planted 1'-0" from the public sidewalk, and on 3'-0" centres, or 3'-0" apart.  There is not a hedging shrub in cultivation that should be planted 1'-0" from the sidewalk, because every plant needs space to grow.  However, RedCedars in particular need a lot of space.

For instance, RedCedars grow in the wild to 170-250' (50-70 meters). One of the features of a red cedar is its buttressed trunk which can be 6'-0" in diameter at maturity.  Although these cedars will never reach those dimensions, they will easily and quickly form a hedge 6'-0" deep and 10'-0" high.

My guess is the homeowner requested an inexpensive, fast growing hedge for privacy. The RedCedar hedge will definitely provide privacy for the homeowner quickly, and it is the least expensive of hedging shrubs.  But the hedge will not stop growing once it has provided the privacy;  the hedge will continue growing for years, and for years the homeowner will have to pay to have this hedge trimmed.

Hedges that are repeatedly pruned hard become stressed.
Hedges that grow beyond their required height are
expensive to remove.

All formal hedges have to be trimmed regularly to maintain shape, width and height.  But when a hedge is planted so close to a public sidewalk, the public's right of way becomes an issue.  There are also often municipal issues of not obstructing an area within 2'-0" of a public sidewalk, and in this case, site lines at an intersection.

Even with pruning, the trees in this hedge will continue to grow in girth, and the trunks and roots of the RedCedars will eventually lift the public sidewalk, making it uneven.  The solution to levelling the sidewalk may be to remove the concrete, cut all the roots of the hedge, and re-pour the sidewalk.  This will be a solution for the sidewalk, but not a solution for the hedge.

A better solution is to choose an appropriate hedging material during the design process. The appropriate hedging material may be more expensive initially, but will be cost effective during its lifetime.