Ask the Expert! June 19 - 25

Pollinator week Ask the Expert

In celebration of 2023 Pollinator Week (June 19-25), we invited you to ask our panel of experts on any questions you had on insects and pollinator-friendly plants. Thank you for sending in your questions! Look below to see if your question has been answered.

We would like to thank our distinguished experts for participating in our Ask the Expert event:

  • Robert Currie, Entomologist, University of Manitoba
  • Linda Dietrick, Master Gardener
  • John Morgan, Prairie Ecologist, Biologist
  • Diana Bizecki Robson, Curator of Botany, Manitoba Museum
  • John Skinner, Skinner Native Seeds
  • Cathy Shaluk, Master Gardener & Educator, Monarch Teacher's Network


1. I would love to know whether neem oil is okay to use as an insect deterrent. Websites contradict each other and some even say it is maybe okay depending on use. Can you provide some insight?

Neem oil is a natural product that is derived from the Neem tree in Africa. It is therefore classified as a botanical insecticide and can be effective in controlling a variety of insect pests. The main active compound as it relates to insect control is azadirachtin. Beneficial properties of this material for insect control include repellency, feeding and oviposition deterrence, insect growth regulatory activity.

It is generally believed to be of low hazard to pollinators relative to other insecticide and has low mammalian toxicity, and rapid degradation making it an attractive compound if a pesticide must be used. Some sublethal effects against wild bees can occur so if it must be used in countrys where it is legal to do so it is best to avoid appying when bees are not active and to avoid applications during flowering where it is feasible to do so.

Neem is NOT registered for general use in Canada so should not be applied to flower or vegetable gardens in Manitoba as it is not legal to do so. The only neem based product that is registered (Treeazin) in Canada is only for by commerial applicators and is restricted for use against tree pests such as the emerald ash borer.

-Dr. Rob Currie, Entomologist, University of Manitoba

2. It’s been recommended that homeowners should be either installing motion-sensor lights or else turning out exterior lights at night on our homes. How will doing this help the moth populations and the birds

Anthropogenic (human produced) light sources can attract species of insects such as moths that pollinate flowers that bloom during the night. Flowers that are pollinated by insects during the evening can often be identified by their fragrant smell in the evening, their appearance (typically white with highly bisected flowers) that make them attractive to moths. Some studies have shown that nocturnal light sources disrupt pollination networks thus lowering reproductive success of the plants they pollinate (e.g. Knop et al. 2017, Nature, 548: 206-209).

Turning out yard lights or using motion detector lights if done on a broad scale could help to mitigate some of these effects especially in rural areas where there are fewer street lights.

-Dr. Rob Currie, Entomologist, University of Manitoba

3. Can you recommend some native plants that grow well in full shade? And are there some that grow well in dry, shady areas?

Great question! Lots of urban gardeners like me treasure the mature trees that shade our yards, not only keeping us cool, but also providing food and habitat for pollinators. I have found there are many native plants that thrive in the shade of our trees and human-built structures.

If you are looking for shrubs, the native dogwoods, bush honeysuckle (Diervilla lonicera), and nannyberry (Viburnum lentago) are well adapted to the shade of the tree understory. The same is true of these native vines: wild hops, Virginia creeper, wild grape, and the wild clematis known as western virgin’s bower (Clematis ligusticifolia), which will quickly cover a fence and has sweetly scented white flowers in June.

For your perennial beds, why not start by filling them with weed-smothering ground covers like those you might find in a local forest: Virginia creeper again, wild ginger, baneberry, wild sarsaparilla, sweet-scented bedstraw (Galium triflorum), Solomon’s seal (Polygonatum biflorum), star-flowered or false Solomon’s seal (Maianthemum stellatum, a.k.a. Smilacina stellata), oak fern (Gymnocarpium dryopteris), native ostrich fern, or western Canada violet. For a grassy meadow look, purple oat grass (Schizachne purpurascens) is happy in shade, as are oak sedge (Carex pensylvanica) and Sprengel’s sedge (Carex sprengelii). Oak sedge will gradually spread to fill in, as will wild strawberry (Fragaria virginiana var. glauca), though you won’t get as many berries in the shade.

All of these plants will tolerate a fair bit of dryness once established, as well as providing food and habitat for all kinds of beneficial creatures. If you have super-dry conditions such as that found under a spruce tree, I recommend star-flowered Solomon’s seal.

For seasonal colour and to offer pollen and nectar for pollinators, you could add these shade-tolerant wildflowers: wild red columbine, marsh marigold (requires moisture), bunchberry, touch-me-not (an annual native impatiens), tall bluebells, bloodroot, Lindley’s and calico aster (Symphyotrichum ciliolatum, S. lateriflorum), and any of the native violets. Taller shade-tolerant natives include tall coneflower (Rudbeckia laciniata) and tall meadow rue (Thalicturm dasycarpum). I also recommend goatsbeard (Aruncus dioicus), which is native to eastern North America but still highly attractive to our local native bees.

-Linda Dietrick, Master Gardener

4. What are good resources for finding info on companion planting for native flowers. I would love to learn in-depth knowledge or what each Plant grows near (ex. Trees or other flowers) and what habitat and why. I have been searching for information on what this means for the plants symbiotic relationships to it's environment beyond what pollinators like their flowers.

The best sources for companion planting are plant lists from native prairies in your area. For example, Winnipeg's Living Prairie Museum & Oak Hammock Marsh have checklists of all the plants that occur on the tall grass prairies there.

Our book, Restoring Canada's Native Prairies, has native plant lists for prairies in western Canada & Ontario. It is available on & in all public libraries across the prairies. Native plant nurseries, such as Prairie Flora, Prairie Originals & PS Botanicals have excellent recommendations on what plants do well together.

I am not aware of any one specific resource that would answer all your questions on this topic. Experimenting with different species combinations in your own yard is the best way to learn. Observe carefully & keep track of your results. Native plants frequently move around in plantings until they find their favourite spots & species associations. Every property is different. The more diverse your planting is, the more chances you will have they will find their own best locations. Good luck & happy planting!!

-John Morgan, Prairie Ecologist, Biologist

5. Hi John [Skinner], I was excited to learn that you gave a presentation in January at a national seed conference in Washington DC. I believe your presentation was about restoration of native habitat in Canada. How would the public be able to access the content of your talk? I think many of us would be very interested.

I did give a presentation in Washington DC at the National Native Seed Conference in March of this year with Dr Stephanie Frischie of the Xerces Society. The presentation was about the Cheerios General Mills agricultural pollinator habitat program in Manitoba and Saskatchewan and the impact of my involvement in the program on my business and the development of a seed supply for local wildflowers. The event was fascinating for me, as I got to learn about restoration in the States, which takes place on a far larger scale than here in Canada. Unfortunately our presentation wasn’t recorded so it’s not available on the internet. I do have my slides, though, and would be very happy to discuss it with anyone who is interested.

-John Skinner, Skinner Native Seeds

6. Can you help identify this insect? It would be nice to learn what insect is burrowing in multiple places between and under our cement patio blocks, leaving small mounds of sand like ants (picture attached). There are many that hover about these mounds. It almost appears that they have a preference for which hole they go into, maybe. They don't seem to be aggressive as I am quite close in trying to capture them with my camera, but they hover and move about too quickly and the same goes for how quick they scoot into the hole's entrance once they have decided that it is indeed the one they want. 


crabnoid wasp

I suspect that what you have is some type of Crabronid wasp, possibly an Ectemnius sp. (Source: Prairie Pollination).  They are typically hairless and often black with yellow stripes on their abdomens and legs.  Some species nest in the ground and will hover over their nests.  They typically capture and paralyze other insects, like flies or grasshoppers, to feed their young, but the adults also drink nectar to nourish themselves. 

Watch closely to see if the adults are bringing any prey items into the nests.  I haven’t found them to be particularly aggressive, unlike Paper Wasps that will try to fight you for your food!  You might want to check out; it is a great website to go to see images of all kinds of insects.

-Dr. Diana Bizecki Robson, Curator of Botany, Manitoba Museum

7. I’m thrilled to be seeing many monarchs this season and have had dozens of caterpillars on my milkweed plants! I’m curious to know what the requirements are for becoming a monarch waystation. I believe that education is key and I would welcome the opportunity to certify my garden if/when it meets the criteria.

Thank you for your question regarding the Monarch Waystation program. This has been a fabulous year for the number of Monarch Butterflies reaching Manitoba this spring.

Terrific you would like to consider registering your yard as a Waystation. I have included the Monarch Watch program information and requirements:  Monarch Watch Monarch Waystation Program

-Cathy Shaluk, Master Gardener & Educator, Monarch Teacher's Network



Below are the questions and answers from last year's Ask the Expert session (2022):

I have had this flower come up every year but I'm not sure what it is. I think it is an Iris but not sure. Can you help identify this plant? (Picture below)

Iris ochroleuca Iris orientalis

It appears to be an iris of the species Iris orientalis, formerly known as Iris ochroleuca. It belongs to the Spuria class of irises, of which there are many garden cultivars, but I've never seen this species in local gardens or nurseries, so I think it must be pretty rare here. According to Wikipedia, it originates from Turkey and Greece. In the UK it's known as Turkish iris, while in the US it is usually called yellow banded iris. Apparently it is hardy to zone 4, which means it will overwinter here in a reasonably protected spot. Thanks for sharing the lovely photo! I should also mention that Manitoba has a wild iris, Iris versicolor or blue flag iris. It's an excellent garden plant that prefers a moist to wet site, as canoers of our lakes will know. Pollinators like bees and hummingbirds enjoy its blooms in early summer.

-Linda Dietrick, Master Gardener

I was weeding a pollinator garden in my neighbourhood which I planted last year. I noticed this "bug" on the New England Aster and wondered what it was. I was hoping it was a caterpillar but doesn't look like one. Can you take a look at this picture and help me identify this bug? (Picture below)
lady beetle larvae

The insect on your asters is a lady beetle larvae. This is the immature stage of the common insect known as a lady beetle or ladybug. It is a beneficial insect in that it is a predator and is particularly effective in keeping insects like aphids under control without the use of pesticides. The larvae will turn into an inactive resting stage called a pupae, then emerge as the familiar orange coloured lady beetle with a number of black spots that you are likely more familiar with. It is also a voracious predator of aphids and some other insects.

-Dr. Rob Currie, Entomologist, University of Manitoba

Today, I was in my garage and noticed this insect flying around. It is not very big, but wasn't sure the name of the butterfly/moth? Do you know what it is? (Picture below)
owlet moth

I think it is a species of owlet moth (Noctuidae) but I can’t say for sure which genus it is from based on the image. The University of Alberta has a good moth website moths that can be accessed here: 

-Diana Bizecki Robson, Curator of Botany, Manitoba Museum

If I want to naturalize my lawn to better host pollinators, what plants would work for a Wolseley Winnipeg yard? Is there an optimum process for doing this?

Native Manitoba grasses and wildflowers are best to host pollinators. Establishing them into an existing lawn is a multi-year process. Best to start small and consult native MB nurseries:

-John Morgan, Prairie Ecologist, Biologist

I have limited space and budget on my property but I want to maximize habitat in the space I have. What are the top 2 or 3 perennials, shrubs and trees for me to focus on?

Here are some of my favourites, but there are lots of good choices:

  • Trees - 1. Western Mountain Ash - smallish tree to 12', beautiful blooms for bees and fruit for birds. 2. American Basswood - Tilia Americana. Eventually will make a large tree, but has a nice form and bees love the flowers.
  • Shrubs - Potentilla fruticosa - Shrubby cinquefoil. Long bloom period and yellow flowers.
  • Perennials - Antennaria - Pussytoes. Will grow as part of the lawn. Early blooming for pollinators. Prairie Flax - Linum lewisii. Beautiful blue flowers. Relatively long bloom period early in the season. Purple prairie clover - Dalea purpurea. Late season, blooms for a long period and pollinators love it.

Of course, there are a lot of great choices - these are just some of my favourites!

-John Skinner, Skinner Native Seeds

How long should I wait in the spring before I “clean up” my garden? Is it ok to get a jump on spring cleaning and keep dead material in an open box?

Cut back your last year plants as late as you can, at least after this year's perennials are up and growing well. Use the old stems/leaves as a weed control mulch to conserve the overwintering pollinators hibernating in the previous year's stems.

-John Morgan, Prairie Ecologist, Biologist

Is it beneficial to keep a water basin / bird bath in the yard for pollinators? What do I need to consider so I don’t do more harm than good?

Bees like most creatures require water. While they can gain some moisture from sources like nectar or water condensed on plant surfaces, they often need to collect it. This is particularly true for the social species that may use it to help cool their nests. Some bees will collect and evaporate water in colonies as a form of "air conditioning". If bees are not provided with a source of water they may collect it from areas where they will become a nusiance such as water taps, swimming pools, or air conditioners. Putting a source of water out early in the season will help to provide for their needs and prevent them from "training" to other sources.

Water sources should provide a place for them to land without drowning (rocks or wooden floats for example). You also need to ensure you are not providing a breeeding site for mosquitoes. Inspecting the source for mosquito larvae and pupae should be done about every five days and water should be dumped and replaced if you find developing mosquitoes.

-Dr. Rob Currie, Entomologist, University of Manitoba

I have a wooden bee house with holes drilled into it. Last year I was thrilled to see all of them occupied but now I am not sure when and how to clean it out. Any suggestions?

Solitary bees utilize any sort of tunnel to construct cells, provision them with a mixture of pollen and nectar and deposit and egg on the pollen lump. In Manitoba, the egg usually hatches into a larvae that completes development to a prepupal stage (for many species) where it will overwinter and then continue development the following spring. You do not want to destroy these cells as they form the next generation of bees so any "nest cleaning" should not be done until they have all emerged.

If you have a nest that is empty and no longer harbours developing bees it can be cleaned with a pipe cleaner and treated with a 3 to 5% solution of bleach to control foliar molds and pathogens. If bees are already utilizing the nest the best approach may be to let it go for another season and then emerge bees into a container and release them the following spring.

-Dr. Rob Currie, Entomologist, University of Manitoba

I was weeding a particularly overgrown garden bed that had no flowers blooming yet and a whole bunch of bees started flying out of the greenery. I think they were ground nesting bees. Very exciting! So my question is about timing: what is the window I have between waiting for bees to emerge from their burrow, when I can start working the soil and when I should stop?

If bees are emerging from an overwintering site the soil can probably be worked to the extent needed in about mid May. If you have ground nesting bees they may be provisioning larvae in tunnels in the ground and tilling that section of soil would disrupt the population. If that patch of soil or lawn could be left undisturbed it would be best for the bees.

-Dr. Rob Currie, Entomologist, University of Manitoba

My pollinator garden is half in the sun and the other half is in shade, of course the plants on the sunny half are doing great but the shady side is struggling. Do you know of any native plants that would do well in shade?

Here is a list of native plants that are shade-loving: Wood columbine, Canada anemone, Canada violet, Meadow rue, Jewel weed, Fringed brome, Tall bluebells. Kelly at Prairie Originals has a more extensive list of shade-loving plants on her website - please visit

-John Skinner, Skinner Native Seeds

Why is it important for pollinators to have flowers blooming in succession throughout the season? Why is having a diversity of plants important in the garden?

Some pollinators are long-lived either as individuals or as colonies that build populations throughout the season (from spring to the first hard frost in fall). Most plants, in contrast, stay in bloom for comparatively short periods and thus a single species of flower will not provide enough support to keep many bees alive throughout the entire season. Other species of bees are specialists and have to synchronize thier emergence with a particular species (for example willow or sunflower). If those plants are not present the specialist bees will not be able to survive or have reduced success. Flower diversity (particularly with native species of plants) is very important to support the diverse range of rare but important specialists that inhabit our landscapes.

-Dr. Rob Currie, Entomologist, University of Manitoba

We are looking into building a bat house and a purple martin house on our acreage next year for mosquito and wasp control. Would these scare away the pollinators?

Great question! Bats are nocturnal and forage on a wide variety of insects such as mosquitoes and moths at night. Bees and many insect that we have in Manitoba forage almost exclusively during the day and so would not be affected by bat predation.

There are flowers that bloom in the evening, often white in colour with highly disected blossoms and they typically release a strong perfume odour in the evening to attract night flying insects such as moths. These moths would be a target for bats but enough moths would likely survive to satisfy the pollination requirements of plants.

Bats emit a radar and use it to detect and capture moths, but moths have evolved some fascinating defence capabilities. Some have radar detectors and take wild evasive manuvers to avoid caputure! It has also been recently discovered that some have radar jamming mechanisms (that operate by rubbing their genitals together and against their bodies) which is thought to reduce the effectiveness of the radar. In some areas of the world bats themselves act as pollinators and their is a pollination syndrome named after bat loving flowers called Chiropterophilly.

-Dr. Rob Currie, Entomologist, University of Manitoba