British Columbia: drought resistant, fast growing, evergreen tree

Now that we're all seriously considering how to deal with recurring drought in the Lower Mainland (and installing air conditioning), I may have to rejig my back garden where I have emerald cedars providing a screen against a tall house behind me that's close to the fence. They're showing the stress of several summers of drought. I'm on the Sunshine Coast which is now on level 4 water restriction meaning no potable water to be used on the garden and this seems to be the future. Rain barrels don't last long when you've got quite a few cedars, rhodos etc. and several months of little to no rain, never mind the extreme heat we've recently endured. So, if the cedars do die in the next few years, what could replace them that would tolerate drought, grow quickly to at least 15-20', but not much more than that. I've lost my vanderwolf pine to white pine blister rust, so now leery of pines. The garden where I need screen trees is in a north east orientation which normally has lots of shade and moss in the winter months. Tricky. Any ideas?

 

Leyland Cypress (Cupressus × leylandii) are often planted as hedge trees in the area where I live in central Vancouver Island and elsewhere because they are quite drought-tolerant (certainly require less water than Emerald Cedars), grow quickly and are not bothered by deer (except maybe in rutting season). The downside is that they require frequent pruning. I can't say if there is too much shade where you would plant them but I expect they'd need about the same amount of sunshine as the Emerald Cedars you are growing now.

I sure do feel for you with the water restrictions you must observe. Here on Vancouver Island, we're still at Level 3 and I have my fingers crossed that we will not move to Level 4. Even if we do, I'd still be allowed to hand water . . . is that a possibility for you on the Sunshine Coast?

I've long thought rain barrels were a waste of time and money. They fill quickly when you don't really need the water but empty quickly sit empty during the dry months.

 

Thanks for your response. I've seen Leyland Cypress mentioned before when I've been researching screening trees. The need for keeping their height under control made me pause, but I'll look into them some more. On the Sunshine Coast we can't use any water out of taps (potable water), only the grey water we collect in kitchen sinks from hand washing, washing veggies etc., bathroom sinks and showers. A lot of containers all over the place trying to collect every bit of water we can for the garden. I have 3 large rain barrels and a few garbage cans of winter collected water, but as you say, they don't last long when you've got quite a few cedars and other bushes you want to save. I've been trying to use only grey water so far as I don't know how long before we get the soaking rains that will get down to tree roots through the drought crust. The couple of days of rain we've had so far has been light and spotty, not nearly enough to make a difference. We're actually under the threat of running out of water altogether, nothing from taps and for firefighting unless we get some rain and/or the SCRD is able to get permission from provincial/Federal levels to tap into other sources of water. People, including me, have been buying big containers of water against that possibility which will become earthquake prep if not needed.

 

A few years ago, a very well-known gardener is this area said to me, "You can't not water a garden." Hers was 50 years old - 5 acres - so she put in an expensive well/irrigation system . . . not a luxury many can afford. It is hard to see plants in your garden suffer and die for lack of water but there's really no alternative. People come first. I just hope the decision-makers aren't allowing more building permits than the water supply can support.

EDIT: We have just moved to Level 4 Watering Restrictions here in the RDN -
"The district says hand watering or drip irrigation is only permitted for fruit and vegetable gardens for a maximum of two hours per day between 7 and 10 a.m. or 7 and 10 p.m."

 

I've put in drip irrigation along the edge of the garden where the trees are and just recently put some in the front garden to target a chestnut tree and specific bushes, but on level 4 here, we're not allowed to use drip irrigation. Unfortunately, quite apart from cost of digging a well, I have a small suburban property, so that's not an option. Yesterday the local govt. in an emergency meeting lifted the ban for registered farms, but will continue with new housing developments and there is a lot of new growth on the SC. I suspect they are caught between the need for income and an infrastructure that is falling behind. We need to be able to tap into new wells and lakes, but there are provincial parks involved, so problems with permissions. People are getting rid of grass lawns and moving toward xeriscaping. Even the big cedars in the forests are being affected by several years of summertime drought, so it appears the climate is shifting away from a friendly environment for that kind of tree, including my emerald cedars. So sad to see them struggling.

 

Last year I bought 5 acres with the intent of building a destination garden. Recently I was informed by a neighbor that the HOA has sent out a seasonal letter during the last several years saying that watering was not permitted due to the community well getting low. Meanwhile agricultural operations all around the local area continue to use water cannons that are quite visibly shooting most of their considerable output into the wind, to be blown away and wasted.

 

I hope you will not have to abandon your plans of building a destination garden. With your knowledge and experience, I'm sure it would be a very special place. Could you build a large holding pond lined with butyl rubber to collect water during the rainy months? All of us who have to ration water in our gardens are frustrated to see those who are allowed free use of it, waste it.

 

If it’s not a vegetable patch, a thoughtfully designed garden should not need any watering.
(My two cents)
Newly planted stuff and things in pots are the exception to my rule.

 

With all respect, Nic, I completely disagree that, as a general rule, "a thoughtfully designed garden should not need any watering". Thoughtfully planned or not, few plants can survive on less than half an inch of water a month for months on end during periods of very high heat (some days exceeding 100F). That seems to becoming the new reality here on the east coast of Vancouver Island, BC.

Here where I live on the so-called 'wet' coast of BC, gardens have been thriving for decades with little supplemental water other than what falls from the sky. Now, suddenly, we are faced with dramatic changes that are more likely to become the norm than the exception. This year, many communities on Vancouver Island broke 70-year-old records by up to 10 degrees Celsius! Even native plants that have thrived in this area for of thousands of years are suffering, dying.

I don't think many gardeners are ready to pull up their established gardens and plant something more 'thoughtful' but inevitable attrition will require careful consideration about what to put in the empty spaces. If my plant choices were restricted to those that need only 1/2 inch of water a month as well as tolerate high heat, I wouldn't garden anymore.

 

I stand firmly behind my original statement.
If you are using water to sustain your garden you are part of the problem, so sorry to say that but it is true.
Even collecting rain water that is supposed to go into the ground, or using a private water well… but the worst of course is using city water supply.
If the climate is changing, one has to adapt. And changing a garden can be an exciting project.
Interesting read about the water shortage in the west:
The Well Fixer’s Warning

 

Just a question out of curiosity: are the UBC Botanical Gardens watered artificially or do they rely on natural rain only?

 

Where exactly goes the rain water you collect and pour for your plants? Not into the ground?
If you plant something, you'll affect water regime in the soil anyways.
Of course, if thoughtful design includes selection of moist enough location, that renders watering obsolete, then I agree your statement.

 

UBC Botanical Gardens are irrigated. The curators try to use minimal water. Water drains naturally from adjacent areas and flows across the Garden as well. Even still plants are sometimes lost due to drought. In BC and Washington State water is mainly collected in mountain reservoirs and dammed river lakes. I don't think there is much extraction from aquifers here. The climate is such that most of the rain falls in a 9 month period with 3 very dry months in summer. I think in an environment like this, it is possible to collect surface water without making a big impact on stream flows or depleting the groundwater. The land around here is mountainous. The water will all quickly flow to the ocean if not channeled into reservoirs. This type of water use can serve human needs and then return the water to the ground. (Not to say there are not a lot of environmental considerations, sufficient stream flow is needed for salmon spawning for example and there are contamination and energy issues.)

I saw a wonderful segment in a documentary recently where a native elder in Arizona grew blue corn in a completely unirrigated garden--I repeat in Arizona. The plants were in clumps spaced very far apart. He was harvesting some nice full ears of grain corn.

8 billion people probably cannot be fed without irrigation.

 

Don't forget that water stored through the winter in mountain dams and rationed out during the dry months is still eventually returned to the ocean if not to aquifers.

It is vitally important not to let our gardens die for lack of water in the 3 or 4 months when we have virtually no rain considering that such an abundance falls during the remaining 8 or 9 months. The issue here is more one of storage than lack of water.

I know from my own experience that if I did not water, most plants I presently grow plus many of the native plants (formerly quite drought-tolerant) would die. So too would countless other members of the ecosystem they share - the slugs, frogs, snakes, bees, butterflies and birds. The numbers of these creatures are noticeably diminishing in the area already. Every living thing needs at least some water . . . the trick is to use it judiciously not just turn off the tap and say 'adapt'. To suggest that a thoughtfully planned garden comprising plants that need only 1/2 inch month for months one end is simply unrealistic and, frankly, unnecessary.

 

What would a thoughtfully designed garden look like? What measures/types of plants would be put in place. I suppose you're not talking about xeriscaping which some gardeners are turning to in a limited way. Any plant that survives in desert like conditions (almost no natural water and extreme heat) which seems to be our summers of the future would not do well in the soggy conditions for the rest of the year, so I assume that's not the sort of thing your referring to. Could you expand on what measures would work for our new summer time conditions? My temperate climate plants--rhodos, cedars were simply blasted by the heat events this summer and put under further stress by lack of sufficient water. Here on the Sunshine Coast, there's no end in sight for the ban on outdoor watering and so far no signs of the kind of rainfall that would save the plants and refill the lake that normally supplies our communities.

 

We just had 6.5 inches of rain in the span of 24 hours… normally it’s about 4-4.5 a month year round. I understand that this is quite different from your climate. But we also frequently have stretches of several weeks during the summer with no rain and temperatures in the high 80s and low 90s.
I have learned to work with local plants as much as possible. Use volunteer seedlings and transplant them if necessary. Remove as much as I want and add very little (if any) non-native species in problematic areas of the yard. Less is more.
For example, our back yard is almost entirely rocks, covered with only few inches of soil. In one particular spot, when we first moved into the house, the previous owners had planted 5 Thuja trees. They were evenly spaced, about 8 feet tall, stripped bare by deer at the base (4 or 5 feet). They were clearly struggling, looked terrible and seemed completely out of place.
The first spring I cut them down and planted a variety of evergreen shrubs and watered them every other day all summer long. They were thriving. The following summer I didn’t water at all and some didn’t make it. The rest did not grow at all. So I removed them all.
What I did next is to leave volunteer seedlings of Tsuga canadensis and Juniperus virginiana to grow freely in the same area, and they are now filling the space nicely without any watering.
My advice is to look at what is thriving in your neighborhood and decide on a replacement based on that. Also, embrace moss as a ground cover. It does not require any watering, only weeding.
It can dry out completely during hot summer days, but it springs back to life in the evening/night/morning or after a rain.
I completely agree that food producing plants need irrigation. Also, botanical gardens, because they exhibit plants not native to a certain area, also require the frequent use of water.
Here are examples of moss on a hot summer day and in the morning (or after a rain, same result).

 

Thanks for your informative reply. I assume you must have been under the impact of Ida. I hope you and your family are safe and have not suffered damage to homes and gardens. The images on the news are frightening. My back garden is in the shade much of the year and happily grows moss though it has more or less disappeared into the general straw brown of everything on the ground. We haven't had enough rain to revive it. However, the various types of creeping plants I planted--scotch and Irish moss, thymes--after looking as though they had died off in the earlier part of the drought, seem to have revived and are actively spreading, perhaps with condensation from cooler nights. The drooping hemlock also seems to be tolerating the minimal watering it gets from grey water much better than the cedars. I'm sure gardeners in the PNW area are all going through a similar rethinking of their gardens under our new conditions and preparing for an intensification of drought and rainfall events.

 

I’m going to jump in here out of personal interest. When I first got into gardening, I dreamed of the lush tropical-type landscapes I enjoyed in places like Hawaii. This had me planting palms, bananas, ferns, etc. They are still apart of my garden. Over the past 5 years or so, this interest has dramatically shifted. My obsession with manzanita trees, which detest irrigation in the warmer summer months, has caused me to plunge into no water and low water garden beds. From my experience, these can be beautiful lush gardens but require some experimentation, research, and the willingness to sometimes fail. What I think we could all agree is that commercial landscapes and new landscapes need to better reflect the changing nature of our climate. Particularly in the case for commercial planting strips etc., imagine this past summers extreme heat in non-irrigated garden beds surrounded on all sides by concrete and radiant heat from buildings. Lots of the great work in Portland is an example of planting for summer heat/drought. I still need to water some of my plants, but more and more I’m adapting to zero water zones of the garden and seeing great success.

 

These photos are from a beautiful North Vancouver garden with a cool mix of grey/silver, chartreuse, and greens. The garden was planted about 1.5 years ago and features predominantly drought tolerant plants such as grevillea, manzanita, ozothamnus, etc. It’s a good example of low water gardening with year round interest. Aside from the occasional pruning, once established this will take minimal care.

 

Interesting thread. The garden in Louis A's post does seem to be thriving. The trickiest part in selecting plants for our new climate situation is finding plants that are not only drought resistant, but are not overwhelmed by the amount of constant rain and wet soil we get in the 9 months of rainy weather. It rains more or less from September through to June though in recent years we've had heat outbreaks in spring months that used to be showery and can have sunny stretches in September. And, when the rains come with Pacific storms, we're getting increasing incidents of torrential rain which presents a challenge to drainage of soil. Plants spend a lot of time with their feet in very moist soil. A lot of gardens in coastal BC have large conifers on them, especially on the Coastal mountain slopes, so shade is an issue. Hostas do very well, almost aggressively well. So, finding plants that can tolerate extremes of moisture then lack of moisture will be a challenge.

 

Web site of xeriscape plant enthusiast located near the Lower Mainland in Sequim, Washington State who has been at it for years now. In addition to information about his business the site has a blog and articles.
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