Cultivate a Bat-Friendly garden

Guest Article by BC Community Bat Programs

How can you support the bats?

Spring is at our doorstep! This is the most exciting season for gardeners and nature lovers. This year, we encourage everyone to try something new– gardening for BATS!

The Okanagan is home to at least 14 different species of insect-eating bats – the highest diversity of bats in the province. Supporting pollinators in your garden helps to support bats as they prey on insects at night. Since bats are active from dusk to dawn, having night-blooming flowers in your garden attracts nighttime moths which are a great source of protein for bats. This practice is called moonlight gardening!

Join us in cultivating bat-friendly gardens and nurturing the rich biodiversity of the North Okanagan:

• Start planning early. Opt for native perennial plants – contact local plant nurseries to get your seeds.
• Choose plants with long flowering season or those that flower at different times of the year.
• Variety is key! Pick plants with different flower colour, shape, and fragrance.
• Don’t spring into garden clean up too soon. Wait until temperatures stay consistently above 10°C to start to start raking and pruning. Many pollinators like bees and butterflies are wintering in dead leaves and hollow stems of last-year plants. Bats and snakes sometimes also sleep under leaves and in wood piles.
• Invasive species like burdock can entangle bats and birds. Regularly remove weeds from your garden. If you plan on harvesting burdock, please be responsible and prune out the flowers before they go to seed and become traps for bats.

Invasive species like burdock can entangle bats

If you plan on harvesting burdock, please be responsible and prune out the flowers before they go to seed and become traps for bats.
Photo by: Ken Dzinbal

• Pesticides and chemical fertilizers kill insects and poison wildlife. Practice organic gardening by avoiding chemical products. Try composting to provide organic nutrients in your garden.
• Fact: Bats fertilize gardens with their nitrogen-rich guano (bat poop). Attract bats to have a natural source of guano fertilizer in your garden.
• Switch outdoor light bulbs to “warm” toned or filtered LEDs (under 3,000K) to reduce light pollution that harms bats and other animals. Dimmers, motion sensors, and timers can help to reduce illumination and save energy.
• Keep pets indoors or supervised outdoors to avoid predation on bats and birds.
• Keep dead-standing trees (if it is safe to do so) and mature trees on your property to provide roosting areas for hard-working bats. Peeling tree bark and bark crevices are great homes for bats.
• If you have a lake, creek or wetland by your house – great! Protect natural water-side vegetation; it provides vital food, shelter and water to wildlife.
• Consider adding a garden pond to create a biodiversity oasis in your backyard. Ponds need to be at least 3m wide to serve as drinking sources for bats.

Download the Bat-Friendly Gardening in the Okanagan PDF 

A Pollinator-Friendly Garden

Article by Pat Zander

Pollinator Attraction

My husband and I have always tried to attract birds to our garden. That meant planting shrubs
and perennials that would be sources of food and shelter, and minimizing the use of pesticides
that might harm.

Then we got a hive of honey bees and found that many of the same principles apply. In
particular, bees need a good and consistent source of pollen and nectar-rich flowers during the
warm season. And being very careful with pesticides is even more critical. As they feed, they
are moving pollen around and fertilizing the flowers. The majority of our food crops need these
busy little critters to accomplish this for them before they can produce seeds or fruit.

At one time, I thought there was nothing more entertaining in the garden than watching a
couple of robins bathe in the fountain. However, watching a bee wiggle her way into a tubular
flower and then wiggle back out, covered with pollen, is right up there too. It is a huge bonus
that I am now more aware of all the other pollinators that come our way. With awareness
comes appreciation. I’ve seen three different species of bumblebees “working” the same
patch of flowers, a tiny bee the size of an ant navigating a Hydrangea bloom, and the delicate
scalloping leafcutter bees make on a rose leaf.

Some Familiar Easy to Grow Favourites

Early Spring:
Crocus | Glory of the Snow | Pasque Flowers |  Snowdrops |  Tulips | Hazelnut | Pussywillows

Late Spring:
Allium |  Lilac | Saskatoons | Elderberry | Blossoming Berries |  Blossoming Fruit Trees and Shrubs | Oregon grape

Summer:
Beebalm |  Catmint |  Coneflower |  Dill | Fennel | Globe Thistle | Hyssop |  Jupiter’s Beard | 
Lavender |  Lambs Ears | Mint | Russian Sage | Salvia; | Snapdragons |  Veronica |  Yarrow | Butterfly Bush | Ninebark | Rose of Sharon

Late Summer into Fall:
Autumn Joy Sedum | Sunflowers |  Bluebeard (Caryopteris) | Russian Sage

I have mentioned only the plants in our garden which I know to be pollinator favourites. There
are hundreds more. A quick search on the internet will provide lists of appropriate choices;
borderfreebees.com is a good one. Also, do check out the plant list and images on OXA’s Pollinator Garden in the UnH2O Demonstration Garden on this site. 

It is also worth noting that native plants are the most appropriate for feeding native insect
species. Bonus that they are really easy on the water.

Living in the Okanagan where fruit growing is an important industry, gives us even more reason
to encourage healthy populations of pollinators.

Oh, and if you happen to have a few dandelions in your lawn, you are serving bee candy. Now
there’s an excuse to avoid hours on your knees digging them out.

Article by Mark Godlewski

While it is a complex topic, the main tool used by the horticulture industry to judge which healthy plants likely to survive winter conditions is Plant Hardiness Zones. Most nursery plants are assigned a Plant Hardiness Zone based on their ability to survive winters in a given climate. Those zones range from 1-13 and are based on the harshest historical winter conditions averaged over a period of 20 or 30 years. Zone 1 represents the worst winter conditions.

You can see the Government of Canada plant hardiness zones displayed in map form (see Figure 1). These small-scale maps, however, cannot capture local variation. That is why looking up your municipality is a better option using the following Government of Canada website (it can be a bit slow to load but there should be a newer version published later in 2024).

Canadian Government Plant Hardiness for BC

Figure 1 – Canadian Plant Hardiness for BC

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

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.