GARDENING WITH NATURE

Article by Sigrie Kendrick

Use Fire-smart Plant Choices to Resist Wildfire

When designing landscapes in wildfire-prone areas, homeowners face the challenge of finding a balance between creating beautiful outdoor spaces while maintaining crucial fire protection for their homes.

Fortunately, several native plants offer both aesthetic appeal and FireSmart™ qualities.

Three standout choices, Mock orange (Philadelphus lewisii), Smooth Sumac (Rhus glabra), and Saskatoon Serviceberry (Amelanchier alnifolia) demonstrate that fire-wise landscaping doesn’t mean sacrificing beauty.

Visit the FireSmart website to learn about the best fire-resistant choices for your landscape.

MOCK ORANGE

Philadelphus lewisii, our native Mock Orange, is a deciduous shrub that typically reaches six to 10 feet tall, producing masses of white, fragrant flowers in late spring that evoke the scent of orange blossoms.

It earns its place in fire-smart gardens through several key characteristics–

• From a fire-safety perspective, Mock Orange excels because of its high moisture content and low resin levels. The plant’s broad, green leaves retain substantial water content throughout the growing season, making it less likely to ignite quickly.
• Unlike many ornamental shrubs, Mock Orange doesn’t accumulate significant dead material within its structure, reducing the fuel load when properly maintained. Its deciduous nature means it naturally drops leaves in fall rather than accumulating layers of dry, flammable debris as pyramid cedars tend to.
• Mock Orange responds well to pruning, allowing homeowners to maintain open spacing between branches that helps to prevent fire from easily moving through the plant’s structure.

Position Mock Orange 1.5 to 30 metres away from a structure where it can still provide privacy and beauty without endangering your home.

If you garden in a small space, consider the diminutive cultivar ‘Snowbelle’ which reaches only three to four feet tall and wide.

SMOOTH SUMAC

Rhus glabra, or Smooth Sumac brings both striking ornamental value and practical fire resistance to Okanagan landscapes.

This native shrub features compound leaves that turn brilliant shades of orange and red in autumn, followed by persistent crimson fruit clusters that feed overwintering birds.

Growing eight to 15 feet tall, Smooth Sumac spreads through rhizomes to form colonies, making it excellent for erosion control on slopes.

The fire-smart qualities of smooth sumac lie in its structure and composition–

• The plant maintains relatively high moisture levels in its foliage and stems during active growth.
• Its leaves are broad and flat, with smooth surfaces that don’t trap heat or encourage rapid flame spread.
• While Smooth Sumac does produce some woody material, it lacks the volatile oils found in many drought-tolerant plants.
• This species naturally self-prunes lower branches as it matures, creating vertical separation from ground fuels, a critical feature in fire-safe landscaping.

Regular maintenance enhances Smooth Sumac’s defensive qualities. Remove dead canes annually and thin colonies to prevent excessive density.

Space individual clumps of plants at least 10 feet apart to create natural firebreaks within your landscape.

SASKATOOON

Amelanchier alnifolia, commonly known as Saskatoon, is also suitable for planting along the perimeter of the intermediate zone, which is 1.5 to 10 metres away from a structure. It possesses several characteristics that make it a valuable addition to FireSmart™ landscaping.

This native Okanagan shrub is considered a fire-resistant plant due to its high moisture content in leaves and stems, which helps slow the spread of flames.

It maintains relatively lush foliage throughout the growing season, contributing to its lower flammability rating compared to many conifers or plants with resinous leaves.

Additionally, the Saskatoon can be pruned and maintained at a manageable height, allowing homeowners to keep it as a compact shrub rather than allowing it to develop into a taller bush, which could provide ladder fuel that may carry fire from ground level into the tree canopy.

When planted as part of a well-maintained FireSmart™ landscape with adequate spacing, Amelanchier alnifolia can serve both aesthetic and protective functions, offering beautiful white spring flowers followed by edible berries while contributing to a defensible space around structures in our wildfire-prone valley.

All three of these plants share critical FireSmart™ characteristics– high moisture content, low volatile oil production, deciduous habits that prevent excessive dead material accumulation, and growth habits that make them amenable to maintenance pruning.

Combine them throughout your defensible space, maintaining adequate spacing that prevents fire from jumping between bushes.

Remember that even fire-resistant plants require proper maintenance, such as regular removal of any dead material.

With these three beautiful fire-smart plant choices, you can create a landscape that’s both defensible from fire and drought-tolerant.

Sigrie Kendrick is a master gardener and executive-director of the non-profit Okanagan Xeriscape Association.

GARDENING WITH NATURE

Article by Sigrie Kendrick

Leave only healthy leaves

Many environmentally-conscious homeowners have embraced the practice of leaving fallen leaves in place each fall, while others still shudder at the perceived mess.

The benefits are well-documented as leaves provide valuable habitat for beneficial insects, enrich soil as they decompose, and reduce the volume of waste going to landfills.

However, there are dangers in leaving all leaves to overwinter in place. Instead, there are instances when this eco-friendly practice should be abandoned in favour of thorough leaf removal. Understanding when to rake isn’t just about aesthetics but about protecting the health of your landscape.

When Disease Changes the “Leave the Leaves” Rule

On the other hand, the most compelling reason to remove fallen leaves is the presence of foliar diseases. Many common tree and plant diseases overwinter in fallen foliage, waiting to reinfect plants when spring arrives.

Apple scab,(Venturia inaequalis), one of the most troublesome diseases affecting apple and crabapple trees, occurs in the Okanagan in years with higher than normal rainfall.

Spores, known as ascospores, survive winter in infected leaves on the ground. Come spring, these spores are released during wet weather and carried by wind to newly-emerging leaves, perpetuating the cycle.

If your apple or crabapple trees showed signs of dark, scabby lesions on leaves and fruit during the growing season, removing and destroying those fallen leaves is essential for disease management.

Black spot,(Diplocarpon rosae) the bane of rose gardeners everywhere, follows a similar pattern.

This fungal disease causes distinctive black spots surrounded by yellowing tissue on rose leaves. The pathogen overwinters in fallen leaves and infected canes, ready to splash onto new foliage with spring rains.

Gardeners who’ve battled black spot fungus should never leave infected rose leaves on the ground; instead, these leaves should be bagged and discarded.

I have a client with a large rose garden who requests that I manually remove all leaves from her rose plants in order to prevent disease.

Anthracnose diseases affect numerous trees and shrubs, including London plane trees, dogwoods, maples, and oaks

Anthracnose damage can be easily seen each year in the boulevard plantings of London plane trees around Kelowna. These fungal pathogens cause irregular dead patches on leaves and can lead to severe defoliation and twig dieback. Infected leaves and twigs harbour the fungus through winter, and leaving them in place ensures reinfection the following season.

If your trees displayed the characteristic brown, dead patches along leaf veins, removal of fallen foliage should be a priority.

Practical Reasons Not to Leave the Leaves Everywhere

Beyond disease concerns, there are practical situations when leaf removal is simply necessary.

• Leaves left on hardscape areas can present a slipping or tripping hazard, and they can leave stains on concrete.
• Thick layers of leaves left on lawns will smother grass, creating dead patches that require reseeding come spring. While a light covering can be mulched with a mower and left to decompose, heavy accumulations must be removed or relocated to garden beds where they won’t suffocate desirable plants.
• Leaves that collect in gutters, storm drains, and against foundation walls should always be removed. Clogged gutters can lead to water damage, ice dams, and costly repairs.
• Leaves packed against foundations stay wet and can contribute to moisture problems and provide hiding places for pests seeking winter shelter.

A Balanced Approach

When removal is necessary, proper disposal matters.

Infected leaves should never be composted in home systems, as typical home compost piles don’t reach temperatures high enough to kill all pathogens.

Instead, bag them for municipal collection, bury them deeply away from susceptible plants, or burn them where local regulations permit.

The key to making informed decisions about fall leaf management is observation.

Take note of any disease problems during the growing season.

Photograph symptoms if you’re unsure about identification, and consult with your local Master Gardener chapter or certified arborists when needed.

For trees and gardens that remain healthy throughout the year, leaving leaves in place offers many environmental benefits.

However, when disease is present, removal becomes an important cultural control practice.

Fall leaf management doesn’t have to be an all-or-nothing approach.

You can remove diseased leaves from problem areas while leaving healthy foliage in place elsewhere in your landscape.

This balanced approach protects plant health while still supporting beneficial wildlife and soil organisms.

By understanding when leaves should go and when they can stay, you’ll make better decisions for both your garden’s health and the environment.

The Okanagan Xeriscape Association is grateful for the ongoing financial support of the Okanagan Basin Water Board and is proud to be collaborating on the Make Water Work campaign. Check out the Make Water Work plant list at www.makewaterwork.ca

Sigrie Kendrick is a master gardener and executive-director of the non-profit Okanagan Xeriscape Association.

GARDENING WITH NATURE

Not all plants like the Okanagan

Popular Garden Plants That Struggle Here

Rhododendrons, azaleas, hydrangeas, and most Japanese maples (Acer species) may dominate garden centres but they’re fighting an uphill battle against this valley’s unique environmental conditions.

The most fundamental obstacle these plants face in the Okanagan is soil chemistry.

Rhododendrons, azaleas, and most hydrangeas are acid-loving plants that thrive in soils with a pH between 4.5 and 6.0. Unfortunately, Okanagan soils typically range from neutral to alkaline, often sitting between 7.0 and 8.5 pH. This alkaline environment creates a cascade of problems for acid-preferring plants.

In alkaline soils, essential nutrients become chemically bound and unavailable to plant roots, particularly iron, manganese, and zinc.

The result is chlorosis – that telltale yellowing of leaves while veins remain green – which weakens plants and makes them susceptible to other stresses.

While gardeners can attempt to acidify soil with sulphur or aluminum sulphate, maintaining the necessary pH in naturally alkaline conditions requires constant intervention and expense.

Dry Summers and Low Humidity

The Okanagan’s semi-arid climate presents another insurmountable challenge.

With annual precipitation ranging from just 250-400 mm in many areas, the region experiences genuine water scarcity.

Rhododendrons and azaleas evolved in moist, humid environments where their shallow, fibrous root systems could rely on consistent moisture and lots of organic matter. Their large, thin leaves are designed for environments with high humidity and reliable rainfall—not this valley’s dry summers and low humidity.

Hydrangeas also struggle with the Okanagan’s drought conditions. These plants require consistent soil moisture and suffer significantly when subjected to water stress, which is virtually inevitable during the valley’s hot, dry summers.

Most Japanese maples face similar challenges. These delicate trees prefer consistent moisture and protection from harsh afternoon sun and drying winds – conditions opposite to what the Okanagan typically provides.

Temperature Extremes and Wind Exposure

While the Okanagan enjoys warm summers perfect for viticulture, it also experiences significant temperature fluctuations and harsh winter conditions that stress some of these ornamental plants.

Many rhododendron and azalea varieties that appear hardy on paper struggle with this region’s combination of cold winters followed by rapid spring warm-ups, which can trigger premature budding. That can then be followed by frost damage to those tender new buds.

The valley’s frequent winds compound these problems. Strong, dry winds increase water loss from plant tissues and can physically damage the brittle branches of Japanese maples.

Rhododendrons and azaleas, with their broad evergreen leaves often lose moisture faster than their root systems can replace it.

Why Microclimates Rarely Solve the Problem

Some gardeners attempt to create microclimates to accommodate these plants: installing irrigation systems, adding shade cloth, and amending soil annually.

While occasionally successful in the short term, these solutions often prove unsustainable.

The constant inputs of water, acidifying agents, and organic matter required to maintain suitable conditions are both expensive and environmentally questionable in a water-scarce region. Moreover, even with careful microclimate management, these plants rarely achieve the robust growth and spectacular displays they’re known for in more suitable climates.

The result is often a disappointing performance that doesn’t justify the ongoing investment.

Choosing Plants That Belong Here

Rather than fighting against the Okanagan’s natural conditions, successful valley gardeners embrace plants that thrive in alkaline soils and dry conditions.

Native and adapted plants like penstemon, lavender, yarrow, ornamental grasses, and xeric trees and shrubs provide beauty without the constant struggle.

The Okanagan’s unique climate offers opportunities to grow plants that would struggle elsewhere – Mediterranean herbs, drought-adapted perennials, and heat-loving annuals that coastal gardeners envy.

By choosing plants suited to local conditions, gardeners can create stunning landscapes that celebrate the region’s natural character while conserving precious water resources.

The key to successful Okanagan gardening isn’t forcing unsuitable plants to survive, but discovering the remarkable beauty of plants that naturally call this unique valley home.

A variety of sedums and ornamental grasses instead of coastal perennials

The relationship between plants, pests, and beneficial insects represents a natural system of checks and balances. By supporting these natural predators, we align ourselves with ecological processes refined over millions of years.

Rather than fighting against nature with chemicals and barriers, we can harness these allies to create gardens that not only produce beautiful plants but also support diverse wildlife communities.

The next time you spot a lacewing, soldier beetle, or even a spider in your garden,
consider yourself lucky to be witnessing nature’s pest control experts at work.

Communities in Bloom Award Goes to OXA

Prestigious Showcase Award

Excelling Across Multiple Categories

Our educational component runs deep. Throughout the growing season, the organization hosts workshops, garden tours, and consultations, welcoming thousands of residents who are reimagining their own landscapes. Volunteers, the organization’s lifeblood, staff Seedy Sunday, information sessions, maintain the demonstration gardens, and share their accumulated wisdom about what works in the Okanagan’s unique climate. They continue to spread this knowledge in our community.

The timing of this recognition feels particularly significant, coming just as the garden is celebrating its 15th year. As climate change intensifies pressure on water resources throughout B.C., the practices we champion should be shifting from optional to essential. Municipal water utilities increasingly recommend the general use of xeriscaping principles, and our demonstration garden provides a visual reference point for residents wondering how to implement these practices without sacrificing the beautiful gardens they love.

Communities in Bloom’s evaluation criteria focus on a variety of areas. The Okanagan Xeriscape Association demonstration garden clearly excels across multiple categories, but its strongest showing comes in environmental action and community involvement, with a focus on education.

The Showcase Award also acknowledges the countless volunteer hours put in as OXA members gather to maintain the garden. In a post-COVID era when volunteer organizations often struggle to maintain momentum, OXA has built an engaged community of advocates who understand they’re not just maintaining flower beds but are working together towards a more sustainable future. Their work extends beyond the garden through school programs, partnerships with local governments, and advocacy for water-wise landscaping policies.

For Communities in Bloom, recognizing the Okanagan Xeriscape Association aligns perfectly with the program’s evolving mandate to celebrate not just beauty, but sustainability and environmental stewardship. The demonstration garden represents both ecological and aesthetic beauty—precisely the kind of project that deserves showcase recognition.

As visitors wander through the garden’s pathways this season, admiring the red foliage of the Acer ginnala, the dried coneflowers, and spectacular ornamental grasses, all thriving with minimal water, they’re witnessing more than award-winning landscaping. They’re seeing proof that communities can bloom beautifully even in challenging conditions, and can take inspiration for transforming their own outdoor areas into sustainable spaces.

For a wide range of inspiring information about xeriscape, look through our website to begin your xeriscape journey.

GARDENING WITH NATURE

Article by Sigrie Kendrick

Leave Seed Heads for a Winter Garden

In the world of gardening, we often focus on the fleeting glory of flowers with their vibrant colours and sweet fragrances that mark the peak of a plant’s ornamental appeal.

Yet there’s a quieter, more enduring beauty that emerges after the petals fall—one that extends the garden’s visual interest well beyond the traditional growing season.

Magical Seed Heads

The seed heads of xeric plants offer architectural interest, providing structure, texture, and movement that can transform a fading landscape from dormant to dynamic.

Among the most spectacular examples is Pulsatilla, commonly known as pasque flower or prairie crocus.

After its silky, bell-shaped blooms fade in early spring, this hardy perennial produces seed heads that are nothing short of magical. Each seed develops a long, feathery plume that catches light and moves with the slightest breeze, creating an ethereal display that can last for months.

These silvery, gossamer structures rise above the plant’s finely divided foliage like wisps of smoke. In late afternoon light, a patch of Pulsatilla seed heads becomes luminous, transforming an ordinary garden corner into something special.

The ornamental value of these seed heads extends beyond their immediate beauty. They provide crucial interest during the lean dormant months when many gardens lack structure.

While other perennials retreat underground or become mere stubble or sticks, Pulsatilla’s seed heads create focal points that draw the eye. They’re particularly effective when planted in drifts, where their collective movement creates a sense of flow that animates the garden even on still days.

Pulsatilla seedhead left to add interest to the garden

Seed Heads Making a Bold Statement

Achillea millefolium seedheads in a winter garden

The Drama of Allium Seed Heads

Globe allium seedheads in a fall garden

Sigrie Kendrick is a master gardener and executive-director of the non-profit Okanagan Xeriscape Association.

Our Plant Database features more than 500 plants tested and ideally suited for the unique challenges of gardening in the Okanagan’s extreme climate, iincluding the plants in this article.

GARDENING WITH NATURE

Article by Sigrie Kendrick

Living with Deer in the Okanagan

Living in the beautiful Okanagan Valley comes with many perks, but for gardeners, there is one persistent challenge that stands out: marauding deer.

While deer may be lovely to observe from a distance, they can quickly transform a carefully-cultivated garden into their personal buffet. Understanding deer-resistant plants, particularly those suited to our semi-arid climate, can help you create a thriving landscape that both you and the local wildlife can appreciate—each in your own ways.

Deer are opportunistic feeders, but with surprisingly-discerning palates. They typically avoid plants with certain characteristics that make them either unpalatable or difficult to consume.

The most effective deer-resistant plants share common traits: strong fragrances, fuzzy or textured foliage, bitter or toxic compounds, thorny structures, or tough, leathery leaves.

Plants with high essential oil content, such as herbs and aromatics, are particularly unappealing to deer, as their sensitive noses find these scents overwhelming.

It’s important to emphasize that no plant is completely deer-proof. When food sources are scarce, particularly during harsh winters or drought conditions, deer will eat almost anything, a behavior that was especially obvious in West Kelowna gardens since the 2023 McDougall Creek Fire.

I have a client in Casa Loma who has gardened at her property for decades and accepted that the deer would munch on her Bergenia cordifolia flowers, but more recently, both flowers and foliage are missing.

Deer in an urban garden

Deer-Resistant Plants for a Semi-Arid Climate

The Okanagan’s semi-arid climate, characterized by hot, dry summers and relatively mild winters, makes it ideal for xeric plants, those adapted to dry conditions. These water-wise plants not only conserve our precious water resources but often possess natural deer-resistant qualities.

Many xeric plants have evolved tough, waxy, fuzzy or aromatic foliage as adaptations to conserve moisture—characteristics that coincidentally make them less appealing to browsing animals.

Check out the plant database on this website for examples of some plants we’ve found that normally deter deer.

Perennials: Okanagan deer-resistant, xeric perennials include Achillea cultivars (Yarrow), with its ferny foliage and flat-topped flowers in various colours, and Nepeta (Catmint), which produces spikes of blue flowers and aromatic foliage that deer find objectionable.

Lavender stands out as perhaps the perfect Okanagan deer-resistant plant. Its intense fragrance, drought tolerance, and beautiful purple flowers make it both functional and ornamental.

Similarly, Perovskia atriplifolia (Russian sage) offers aromatic silvery foliage and tall spikes of blue flowers while requiring minimal water once established. Both plants thrive in our alkaline soils and intense summer sun.

Ornamental grasses provide excellent deer resistance while adding movement and texture to the landscape. Helictotrichon sempervirens (Blue Oat Grass), Schizachyrium scoparium (Little Bluestem), and Pennisetum alopecuroides (Fountain Grass) all perform well in our climate, requiring little supplemental irrigation after their first year. Their thin, sharp-edged leaves are simply not appealing to deer.

Shrubs: consider Mahonia species, formally Berberis (Barberry) species, which combine drought tolerance with thorny branches that deer actively avoid.

Potentilla fruticosa (Shrubby Cinquefoil) offers bright flowers throughout the summer in shades of yellow, orange, pink, and white while requiring minimal care. Appreciated more for its foliage than its flowers, Sambucus racemosa “Lemony Lace” (Elderberry) offers yellow-green lace-like foliage with highly dissected leaves and, as of yet, has not been browsed by deer in our West Kelowna demonstration garden.

Annuals: Tagetes tenuifolia (Signet Marigolds), Zinnia elegans (Zinnias), and Antirrhinum majus (Snapdragon) provide bright blooms while being generally deer-resistant, though they’ll need a little regular watering in our dry climate.

Lavender

Designing a Water-Wise Garden with Deer-Resistant Plants

Our Plant Database features more than 500 plants tested and ideally suited for the unique challenges of gardening in the Okanagan’s extreme climate. Deer-resistant plants are included.

Sigrie Kendrick is a master gardener and executive-director of the non-profit Okanagan Xeriscape Association.

GARDENING WITH NATURE

Not all bugs are bad!

Green Lacewings

Green lacewings are perhaps the most beautiful of these beneficial predators. With delicate, transparent wings and bright green bodies, these insects might look fragile, but their larvae are voracious hunters nicknamed ‘aphid lions’ for good reason.

A single lacewing larva can consume up to 200 aphids or other small prey weekly. The adults typically feed on nectar and pollen, making them excellent pollinators, while their offspring handle pest control. Their dual service makes them particularly valuable in any garden ecosystem.

Soldier Beetles

Soldier beetles, related to fireflies but without the light-producing organs, are another powerful ally. These slender, soft-bodied beetles earned their name from their colourful markings resembling British military uniforms.

Both adults and larvae are predatory, targeting aphids, caterpillars, and consuming grasshopper eggs. The adults supplement their diet with pollen, making them useful pollinators as well. Their ability to move easily between plant canopies allows them to hunt pests in multiple garden zones.

Tachinids

The Tachinid fly might not win beauty contests with its bristly appearance, resembling an
overgrown housefly, but its pest-management skills are unmatched. The family Tachinidae is the largest group of insect parasitic flies, with over 1,300 species in North America, many of which are important natural enemies of destructive pests.

These flies parasitize some of gardening’s most notorious pests: caterpillars, beetle larvae, and stink bugs. Female Tachinids lay eggs on or near host insects, and when the eggs hatch, the larvae burrow into the host and consume it from within.

Tachinids have been used extensively in biological control programs. A single species, Lydella thompsoni, can parasitize up to 75 per cent of the highly destructive corn borer larvae.

Orb Weaver Spider

Parasitic wasps

Parasitic wasps represent perhaps the most diverse and specialized group of beneficial insects. Despite their name, they are completely harmless to humans and many are smaller than a grain of rice, escaping the attention of most people.

Their precision targeting of specific pest species makes them invaluable. Braconid wasps, for example, lay eggs inside aphids, causing what gardeners call ‘aphid mummies’, the dried husks of aphids from which adult wasps eventually emerge.

Trichogramma wasps target caterpillar eggs before they can even hatch, while others specialize in beetle larvae or white flies. These wasps are raised commercially around the world and widely released for pest control.

Spiders

Often misunderstood and feared, spiders are among the garden’s most effective generalist predators. A single spider can consume thousands of insects yearly. They maintain balance in the garden ecosystem by capturing flying insects, crawling pests, and even other beneficial insects when populations become too dense.

Orb weavers catch flying pests in their distinctive wheel-shaped webs, while wolf spiders
actively hunt on the ground, capturing soil-dwelling pests that other predators might miss.

How you can help beneficial insects in your garden–

• Plant diverse flowering species, especially members of the carrot, daisy, and mint families, to provide necessary nectar and pollen
• Maintain areas of undisturbed ground cover, such as fallen leaves and leave perennial plants standing in the fall, to offer essential overwintering sites and shelter
• Beneficials require a source of water to survive, so consider providing a shallow dish of water placed in your garden. Change it regularly to prevent its use by mosquito larvae.

The relationship between plants, pests, and beneficial insects represents a natural system of checks and balances. By supporting these natural predators, we align ourselves with ecological processes refined over millions of years.

Rather than fighting against nature with chemicals and barriers, we can harness these allies to create gardens that not only produce beautiful plants but also support diverse wildlife communities.

The next time you spot a lacewing, soldier beetle, or even a spider in your garden,
consider yourself lucky to be witnessing nature’s pest control experts at work.