GARDENING WITH NATURE

Article by Sigrie Kendrick

Think outside the box when prepping for winter

As gardeners, let’s remember to switch up the traditional garden tasks and think in a different direction: perhaps a more environmentally friendly one, that also provides us with more winter garden interest.

For instance, fall is the time of year when ornamental grasses shine. Many are in bloom and at the peak of their beauty.

What poet within us wouldn’t be charmed by the gentle way their graceful seed heads sway in the breeze and dance on the long stalks they’ve been growing all season? Grasses really add movement to your garden—unless you chop them down prematurely.

I recently had the opportunity to consider the importance ornamental grasses hold in our gardens as I cut down literally hundreds of Calamagrostis x acutiflora ‘Karl Foerster’, commonly known as Feather Reed grass, at a client’s property.

So often clients want their grasses razed to the ground before the onset of winter as they
perceive the standing grasses to be “messy” rather than graceful.

Often, land care providers such as landscapers are all too happy to oblige as that means one less task facing them in the spring.

Instead of this perverse desire to tidy in the fall why not take into consideration all the benefits of leaving ornamental grasses over the winter?

What about ecology?

From an ecological standpoint there also are many reasons to leave your ornamental grasses and your perennials standing over the winter. They provide needed habitat for birds and a myriad of other wildlife, as well as for beneficial insects to overwinter.

The seed heads of ornamental grasses and also annuals and perennials which have gone to seed, provide food for birds, who have to forage widely during the colder months, just to survive. They also provide great erosion prevention and slope stability, especially where wildfire has run through the previous season.

The time to shear your ornamental grasses is when you begin to see new growth at the base sometime in spring. Then, don’t toss out the cut grass. Instead, find a spot in your yard where it will be out of your way, but will provide valuable habitat for beneficial insects.

Perennials can also be pruned in early spring, when new growth begins to be visible, while annuals can be pulled out as soon as the ground softens in late winter or early spring.

Remember too that the fallen leaves from deciduous trees should also be left where they fall, rather than being neatly raked up and composted elsewhere in the fall. Those rotting leaves are like gold to a gardener and they provide habitat for insects and wildlife while they decompose over winter.

They also suppress weed growth and protect the roots of perennials over winter and what’s left can be gently dug into the soil come spring.

So, leave the leaves, don’t mow down the grasses and allow perennials and annuals to go to seed (unless they tend to be invasive!)

GARDENING WITH NATURE

Extreme weather taking its toll on gardens

For instance, do not prune your plants in the heat.
Periods of intense heat are stressful for your plants, and pruning, especially thinning, will only serve to
increase this stress.

Removing leaf matter increases the effects of heat on the remaining vegetation, decreasing the humidity
and therefore forcing the remaining leaves to transpire more to cool the plant.

This often has disastrous results.

Another no-no in periods of extreme heat is fertilizing your plants.

Try to make sure your garden has the nutrients necessary for plant health prior to any spike in
temperature.

Adding fertilizer is almost akin to adding salt to your soil as fertilizer essentially makes it harder for your
plants to access the water in the soil. High concentrations of nutrients actually reverse osmosis, the process by which a plant is able to absorb water from the soil. The osmotic pressure is reversed so that the pressure outside the roots becomes greater than inside, making plants unable to access moisture from the soil and they actually lose water back into the surrounding ground.

Planting in the heat of summer is not ideal

Out of necessity, the landscape industry must continue to plant throughout the hottest summer weather but this is far from an ideal situation.

If at all possible delay your planting to the coolness of shorter days in late summer when the ambient air
temperature has decreased but the warm soil necessary for strong root establishment exists.

If you must plant in high heat, at least offer supplemental shade for new plantings by using shade cloth or, in a pinch, an old white sheet.

This shade is even more vital if you are planting in an area of ‘high albedo’. High albedo environments occur where there is a great deal of reflection such as found in a rock garden. This reflective sunlight will damage young plants that can not transpire enough in the high heat to cool their leaves and almost immediately begin exhibiting heat stress.

Unusual snowfall in early November 2022 landed on trees whos leaves had not had time to drop yet

At the other end of the spectrum, severe winter weather caused considerable havoc in Okanagan gardens, as well as in commercial orchards and vineyards.

The weather we have experienced over the last two years has had severe repercussions for our trees, shrubs, perennials, vines, and ornamental grasses.

In the Okanagan Xeriscape Association’s demonstration garden, we saw the complete loss of several Lavenders and Penstemon and extensive injury to several of our trees from the 2022/2023 winter. The Parrotia persica, the Robinia pseudoacacia ‘Twisty Baby’ and the Koelreuteria all have suffered winter damage, and the latter has had to be removed. It’s a heart-breaking loss.

I have heard other Master Gardeners around the valley sharing similar stories of witnessing first-hand deaths of these plants as well as Buddleia, Hybiscus syriacus and various ornamental grasses.

I know that the long warm fall followed by the extreme and abrupt cold experienced in the beginning of November was to blame for much of the damage, similar to your forgotten frozen water bottle exploding, but I wanted to know more. It was hard to ignore that many of our trees held their browned leaves through the winter, never having the chance to drop them as they normally would, with last fall’s sudden lurch from summer into winter.

I consulted with plant pathologist Robert Hogue of Pegasus Horticultural to gain a better understanding of the physiological process which had wreaked such havoc.

Robert explained that it all actually began with the Heat Dome of 2021 when plant tissue was damaged by the extreme heat, registering into the mid-40s.

Like people, plants go into a low-energy state in extreme heat. In survival mode plants do not process as much carbon dioxide, leading to less carbohydrates moving into the roots. This lack of carbon dioxide means the roots receive less sugars which compromises the ability of the roots to absorb the necessary water and nutrients from the soil.

This in turn leads to root death and with the death of large woody roots comes the death of the organism as a whole. This root death also occurred last fall with the abrupt arrival of winter when the roots were still actively growing.

As Robert explained, ‘The abrupt cessation of metabolic activity in the above-ground plant parts meant there was not enough nutrient flow to the roots to complete the suberization process’.

Suberization is the process by which the root walls harden off into corky tissue similar to a callus over a wound. These weakened feeder roots act as an entry for many root pathogens such as Fusarium, Pythium, and Verticillium.

The damage can be immediate, as seen this spring when the plant abruptly died after a seemingly normal leaf-out; but in other cases there will be a slow but inevitable death.

Robert has done extensive research on the hardiness of plant life in the valley and has come to the conclusion that we simply can not rely on traditional plant hardiness ratings in our changing climate.

Gardening with Nature

Article by Sigrie Kendrick

Use native plants to help stabilize slopes

It’s just common sense to look to Mother Nature for advice about solving natural concerns on your landscape, like water, steep slopes and sun exposure or shade.

If recent rain sent a torrent of water sluicing down a steep slope on your property, leaving behind a small creek bed full of rocks and gravel and a pile of soil at the bottom, consider planting native and xeric trees, shrubs, grasses and ground covers which will naturally help to stabilize the slope.

Many residential properties throughout the Okanagan have to deal with steep slopes. Our silty soils are notorious for losing stability when exposed to higher-than-normal volumes of water such as intense rainfalls or a sudden rush of water from water line breaks or leaks.

Josh Smith, a director of the Okanagan Xeriscape Association and manager of XEN Xeriscape Endemic Nursery in West Kelowna explains that a cost-effective, low-maintenance and eco-friendly solution is to take advantage of Mother Nature’s suggestions: plant strong-rooted native and xeriscape plants that are adapted to survive and thrive on our slopes—and in our dry environment—to retain the soil and beautify the space.

Plants just after planting to help stabilize a slope on a residential property in Kelowna last year

Developing a naturalized slope-retention system on your property can take several seasons of monitoring but once it is established, it should require zero maintenance, irrigation, or upkeep.

Some key points for getting started include:

• Control the weeds until the trees, shrubs, grasses or ground covers get established. Some invasive species in the Okanagan are virulent enough to take over a slope and hinder the growth of shrubs and trees you have planted or which seed themselves.
• Grass blends or ground-cover are necessary to occlude weeds and provide surface erosion protection. These species help retain the top 10 to 20 cm of the soil.
• Tree and shrub species are what will provide deep, long-lasting, structural support to help stabilize the slope over the long term.

Smith recommends that if you are choosing plant species for slope retention or naturalized areas, go for a walk in your neighbourhood and look carefully at what is growing on natural slopes in your area. This is a surefire way to ensure you select species suited to your soil and moisture conditions.

A year later, the native plants used to stabilize the slope including a yellow-flowered sedum, grey rabbitbrush, nodding onion, a showy fleabane, kinnikinnick and native grass mix are filling in nicely

Resources

There are many wonderful resources available to help you identify native species and learn more about their growth characteristics. Phone apps like iNaturalist and Seek can help you identify plants. There are also several Okanagan-specific plant identification books, including Trees, Shrubs and Flowers to Know in B.C. by C.P. Lyons, and Plants of Southern Interior B.C. by Parish, Coupe and Lloyd, or you can take photos. They can help you look up the plant characteristics in books or on the Internet. You can also take your photos to a native plant nursery for an expert to help you identify the plant.

OXA has an extensive plant database of ornamental and native species. 

There are also specialized native plant nurseries like XEN in West Kelowna and Sagebrush Nursery in Oliver, and many other nurseries carry a selection of native and xeric species.

Sigrie Kendrick is a Master Gardener and Executive-Director of the Okanagan Xeriscape Association. She can be reached at 778-363-8360 or by email at exec_dir@okanaganxeriscape.org.

Gardening with Nature

Article by Sigrie Kendrick

Keep vital pollinators thriving with your plant choices

Pollinators have great access to food during the summer months when there is a buffet of flowers
blooming on every corner and in every meadow—but what about food for them in early spring and late
fall?

We need to make plant choices for our landscapes that are focused on extending the seasonal banquet
table for these vital little critters by choosing pollinator-friendly plants that provide food for them on the
shoulders of summer.

That should include both native and non-native xeric plants which will require little supplemental irrigation
once established, so we’re not wasting any of our precious resource, water.

It’s estimated that 90 percent of flowering plants need pollinators such as bees and butterflies to
reproduce. That includes a third of the food we eat, such as nuts, fruit, vegetables, and herbs that require
insect pollination.

As we pave over wild lands and build on meadows, we destroy natural habitat and food for pollinators, so
it’s essential that we pay more attention to planting food sources to keep these little insects alive and
thriving and reverse the current trend of their decline.

Recently the Okanagan Xeriscape Association collaborated with Kelowna Rotary Clubs on the creation
of two pollinator gardens located at Sarsons Beach Park, 4398 Hobson Rd. and Cameron Park, 2345
Richter St. in Kelowna.

These gardens have been a year in the making and it was fantastic to finally get shovels in the ground as
OXA, Rotary, and Kelowna’s Parks Department worked together to design and ultimately plant up these
spaces.

Both were designed to have both early and late-blooming perennials to support longer access to food for
pollinators.

Early bloomers in the gardens are the shrub Amelanchier alnifolia, commonly known as Saskatoon berry,
Corsican violets and the native Penstemon fruiticosus or Shrubby Penstemon.

We also included several Achillea millefolium, known commonly as Yarrow, as studies from Simon Fraser
University have shown that this perennial, which is native to the Okanagan, is by far the most appealing
to the largest number of pollinators.

Achillea millefolium will be visited by Hairy Belly Bees, Sweat Bees, Mining Bees, Butterflies, Flies,
Wasps, and Beetles.

With prompt removal of the blooms, we should get 3 bloom periods from the Achillea millefolium as well
as the Nepeta racemosa that we planted. It’s a standout pollinator perennial.

Blooming later in the season, Asclepias speciosa, Showy Milkweed, will support Monarch butterflies as
this perennial is a host plant for females to lay their eggs.

The exceptionally long-blooming Colorado Gold Gazania and Coronado Red Hyssop will round out the
season, blooming until frost.

All of the plants selected were purchased from responsible growers as many nursery plants have been
treated with toxic insecticides, known as neo-nicotinoids, which are harmful to pollinators.

Pollinator Corridor

Rotary Clubs of Kelowna have partnered with Rotary Clubs across the B.C. Interior to establish a
pollinator corridor stretching from Clearwater to Osoyoos to support the growth in populations of bees,
butterflies and other pollinators in our valley.

Visit these public gardens to see the bee-friendly gardens in person and consider planting a pollinator
garden in your own backyard to provide support for these little heroes, who are suffering from the
effects of pollution and climate change.

Sigrie Kendrick is a Master Gardener and Executive-Director of the Okanagan Xeriscape Association. She can be reached at 778-363-8360 or by email at exec_dir@okanaganxeriscape.org.

Gardening with Nature

Article by Sigrie Kendrick

Can we make better choices?

Next to our vital agricultural industry, outdoor landscapes in the Okanagan suck up the most
water.

And there’s no comparison when you consider which use is the most important: we can no
more do without food than we can do without water.

Unfortunately, the Okanagan is a near-desert and water is in short supply, a situation made
much worse by climate change and the resulting extremes in weather such as drought.

While attitudes are changing, wholesale buy-in from civic authorities, the development
community, landscape professionals and nurseries, as well as those of us who plant and water
our gardens and outdoor living spaces is absolutely essential.

No longer can we afford to be so irresponsible as to use plants that require large quantities of
water to stay alive.

With that in mind, the Okanagan Xeriscape Association has joined forces with the Okanagan
Basin Water Board, an entity on which every taxpayer in the region has representation, and its
Okanagan WaterWise program to help educate the whole community about the importance of
replacing water-thirsty landscapes with beautiful ones that require far less water.

When we obliterate natural landscapes to create buildings, and pave our grasslands and forests
over with concrete and asphalt, we simply must re-plant at least some of that with native-type
plants which don’t require large quantities of water to stay alive.

Rewilding

When we obliterate natural landscapes to create buildings and pave our grasslands and forests
over with concrete and asphalt, we simply must re-plant at least some of that with native-type
plants which don’t require large quantities of water to stay alive.

Re-wilding is the term for restoring healthy ecosystems in the landscape that have been
disturbed by humans. Think of the millions of acres of mono-culture that is turf grass currently
planted across this country.

Re-wilding aims to reverse biodiversity loss by using native plants and animal life to rebuild
ecosystems and mitigate climate change.

It is in the hope that we as humans can undo some of the destruction we have wreaked on our
home—earth.

Please consider allocating a portion of your garden to native plants.

Plants native to the Okanagan thrive in our semi-arid valley and support countless pollinators,
birds, and animals. Think of the ripple effect, much as that from a single stone thrown into a
pond.

It’s simplistic to believe that because the bottom of our Okanagan Valley features a sparkling
blue lake, water is not scarce. As soon as we begin to ‘mine’ the lake— use more water than is
replaced by natural precipitation each year— we are in big trouble.

The alternative is for all of us to wake up and give our heads a shake; to enact legislation
requiring that new developments install landscapes that use the principles of xeriscape; to insist
as creators of subdivisions, as home builders and homeowners that our landscapes use
drought-tolerant plants instead of lawn grasses, trees, shrubs and flowers that belong in a
coastal rainforest.

We have to move away from inappropriate landscape choices such as turf grass, cedar hedges
and inappropriate plant selections and instead move toward choices that better mimic our
stunning natural Okanagan environment and support our pollinators, birds, and small mammals.

We humans have to relinquish our control issues and let nature do what she does best— heal.

Sigrie Kendrick is a Master Gardener and Executive-Director of the Okanagan Xeriscape Association. She can be reached at 778-363-8360 or by email at exec_dir@okanaganxeriscape.org.

Gardening with Nature

Article by Sigrie Kendrick

Avoid Pruning Stress

Few things are more irritating than seeing shrubs that the deer have pruned.

However, wrapping them in burlap to help them escape the ravages of these animals who are trying to survive winter’s icy blast is not the answer. Instead, browse our plant database and read our blogs on alternatives to the water-thirsty cedar hedge which is so attractive to deer.

What’s even more irritating is shrubs that have been sheared into box or vase shapes by a lazy landscaper or gardener. On an emotional level, I find it painful to see these trees and shrubs tortured into balls or squares, regardless of their natural form, especially if that natural shape is a particularly attractive one.

Pruning causes stress to the plant and as such should not be done without good reason.

Basic pruning requires little more than the removal of dead, damaged, or diseased wood to maintain the health of the plant.

Sigrie Kendrick is a Master Gardener and Executive-Director of the Okanagan Xeriscape Association. She can be reached at 778-363-8360 or by email at exec_dir@okanaganxeriscape.org.

Gardening with Nature

Article by Sigrie Kendrick

Leave the leaves!

Don’t stress over fall garden clean-up.  Just leave the leaves on the ground where they fall.

I have to question why, as gardeners, we are so obsessed with the big fall clean-up, including raking or blowing all the fallen leaves into piles, shoveling them into plastic bags and sending them off to the landfill—or even to be composted centrally.

It’s a tradition we really should reconsider.

In fact, this is counter-productive behaviour. Instead, we would like to educate everyone about the many benefits of leaving the leaves where they fall in the fall.

Let us mimic what occurs naturally, in contrast to our need to clean, control and manipulate our natural environment.

There’s a reason for everything in nature.

Leaves are nature’s nutrient recyclers.

For example, with the shorter days of light in the fall, the leaves of deciduous trees and shrubs fall to the ground and act as a mulch, which suppresses weeds, protects the roots of perennials from the winter cold and feeds the soil as they decay.

Their decomposition creates rich organic matter in the soil that helps your garden become lush and beautiful.

Leaving your tree, shrub, and perennial ‘mess’ in place over winter also provides a source of food and sanctuary for a whole host of small mammals, birds, and insects.

Sigrie Kendrick is a Master Gardener and Executive-Director of the Okanagan Xeriscape Association. She can be reached at 778-363-8360 or by email at exec_dir@okanaganxeriscape.org.

Gardening with Nature

Article by Sigrie Kendrick

Plant spring bulbs now for xeriscape colour later

In addition to perennials, fall is the ideal time to get a jump on next year’s garden by planting bulbs to provide a pop of colour in the spring garden.

A xeriscape flower that many people don’t think of is the spring-flowering bulbs such as narcissis, crocus, tulips and scillas.

Drought-tolerant or technically, drought-avoidant bulbs, bloom before the heat of the summer season and benefit from dry conditions once they have finished blooming.

Since our mandate is to help educate people about ways to conserve water used on the landscape, promoting spring bulbs is right up there with hiking for a fun fall activity, in my books.

Two of my favourites

One of the earliest bulbs to appear in spring is Winter Aconite (Eranthis Hyemalis) which pokes its cheery yellow head up as early as late February, often in the same time frame as snowdrops, although it is not as common.

It is well worth searching out this bulb as it will naturalize in your garden and in time allow you to share some bulbs with your friends.

It seems that few gardens in the Okanagan are untouched by marauding deer, so homeowners are always on the lookout for plants those pesky animals tend to shun. Another great bulb for the spring garden is the Turkestan onion (Allium karatievense), a member of the onion family. That means it is ‘stinky’ to deer, although not to us, and as such it’s usually not on the menu for our four-legged friends.

The Narcissus Family

Another bulb deer tend to go by without nibbling is the narcissus family.

These can provide up to six weeks of bloom with a selection of early, mid, and late-flowering varieties, plus they are readily sourced at nurseries or big box stores.

One of the varietals that we planted recently in the OXA UnH2O Xeriscape Demonstration Garden on Gordon Drive, is the absolutely-stunning Narcissus poeticus, which is, ironically, one of the oldest daffodils to be cultivated, dating back to ancient times.

I’m enamoured with its simple shape and pure white petals, so different from the brassy yellow we usually associate with daffodils.

No matter what you decide to plant this fall, the anticipation of a colourful array of spring flowers from your fall bulb planting will help you through the dark winter days to come.

Galanthus nivalis