Since warmer weather arrived here in Ottawa at the end of May, there’s been a lot more pollinator activity in my garden. I’ve observed ground and cavity nesting bees, queen bumblebees, and a few butterflies.

Inconvenient (for me) ground nests

I’ve spotted lots of bees going into ground nests all over the front and back gardens. The entrances can go unnoticed, unless you see a bee going in. More often than not, they’re located right next to plants or under dry leaves. There is a clear preference for sloped areas that are south- or west-facing.

Usually I see a bee arrive, and disappear into an invisible hole in the ground, just as I reach to dig up a plant, clear leaves, or pull weeds. Now, I don’t want to work in those areas to avoid damaging nests, or destroying entrances. I have mistakenly done in the past. It’s sad to watch a bee laden with pollen searching for a nest entrance that’s gone, or that it can’t find because I removed the weeds or leaves it used as landmarks.

Oh well, I guess will just have to skip those chores. A messy garden is better for pollinators, anyway. Now I have more time for bee-watching.

Lurking parasitoids

This spring, I noticed two different kinds of insects hovering and zig-zagging close to the ground looking for nests to prey upon. One of them was the odd bee-fly that is furry like a bee, and has a long ‘beak’ for drinking nectar. Females fling their eggs near ground nest entrances. The eggs will then stick to bees as they enter their nests. When the eggs hatch, the bee-fly larvae consume the bee larvae.

I also think I’ve seen a few kleptoparasitic cuckoo bees that have distinctive hairless, red abdomens. (I’m using a picture of a nomadic cuckoo bee on Heather Holm’s Instagram page to tentatively identify the bee, from memory.) Cuckoo bees enter ground nests of other bees to lay their eggs. Once the eggs hatch, the larvae eat pollen left for the original ground-nests’ residents.

It seems like bees abandon nests if they spot parasitoids/kleptoparasitoids nearby. I stopped seeing bee activity in several locations after I had spotted the cuckoo bee flying in the vicinity.

Cavity nests

The only cavity-nests I’ve found so far are for small carpenter bees. In the backyard, they’ve been digging nests in last year’s ironweed stems.

I think I’ve seen mason bees on crabapple flowers and Virginia waterleaf flowers. I wonder where they’re nesting? Perhaps they’re using the cup plant stems I left for them; I cut the stems off about 15 inches from the ground, and added the top part of the stems to a brush pile.

Bumblebee nest

I’m pleased that a queen bumblebee has chosen to make a nest in our yard. A first for us! It is under our shed in a former groundhog den that was later used as a mouse nest. Unfortunately, it is too close to the shed door for my liking, so the area is now fenced off.

We’ve watched numerous bumblebee queens searching around the backyard, especially the perimeter, for nest sites. Almost all of them check out the chipmunk den entrances in our terraced garden. They hover close to the ground, flying back and forth, going under leaves and under rocks, and then coming out again. Here’s a Youtube video I found, called Bumblebee Queen in Search of Potential Nest Locations, that shows the searching flight pattern bumblebee queens use to find nest sites.

Butterfly visitors

We’ve had a few butterflies visiting the garden, usually American Ladies and Red Admirals. (BugGuide has a handy picture for distinguishing American Lady and Painted Lady butterflies.) Other types passed through too quickly for me to photograph or positively identify.

While the calendar was turned to May last month, it felt more like March in Ottawa. The miserable, cool weather limited pollinator activity in the garden, slowed plants emerging from the ground, delayed blooms, and prevented seed germination.

Temperature and pollinator activity

Throughout the month, local gardeners shared my concerns about the dearth of pollinators. One gardener pollinated his apple trees with cotton swabs — just in case. Another wondered if there will be fewer berries for birds on native shrubs this year. And another questioned whether the milkweed would pop up before Monarchs arrived to lay eggs on it?

Last year, I learned that excessive heat harms bees. When the temperature hovered around 40°C last summer, I noticed only a few honey bees in the garden. How urban heat affects bee populations summarizes how high temperatures affect native bees.

On the flip side, what is the impact of cooler than normal temperatures? How warm does it needs to be for native bees to become active? The University of Maine Extension article, Understanding Native Bees, the Great Pollinators: Enhancing Their Habitat in Maine, states:

“The most likely place to find bees is in the flowers of native plants, when the day is sunny, relatively calm, and the temperature is above 70°F. To be active, fly and feed, bees need to be warm. A few species are active below 60°, but most prefer temperatures above 72°. Wind makes flying more difficult because it requires more energy.”

In Celsius, that means it needs to be at least 15.5°C for the more cold-hardy bees, and 22°C for the rest. According to the Weather Network records for May 2019, there were 16 days above 15.5, and only 2 above 22. Not very good weather for native bees. It doesn’t seem that the weather was favourable for honey bees either because I saw only one in my garden this month.

In Bumblebee Economics (at Ottawa Public Library), Bernd Heinrich explains that bumblebees are more tolerant of cooler weather because they can shiver to warm up. I did frequently see queen bumblebees foraging and looking for nest sites in my yard. It will take several weeks, after these queens choose nest locations and lay eggs, before the first brood of workers will be out and about.

Luckily, bees aren’t the only pollinators. Flower flies are also more tolerant of cooler temperatures. I did spot some in the garden, so hopefully they picked up some of the slack.

Most popular flowers

In May, the popular flowers for queen bumblebees were on my ‘PJM’ rhododendron, long-blooming lungwort, and crabapples. The bumblebees liked the flowers so much that they even visited them after they had dropped onto the ground. While I was watching, to my surprise, the queen bumblebees ignored my native perennials, shrubs, and trees.

For smaller native bees and other pollinators, the winners were serviceberries, crabapples, and wild strawberries. It looked like some native bees were nesting under the plentiful strawberry plants that I use as ‘living mulch’ in my hedgerow. Perhaps they preferred foraging close to their nests instead of flying up to the shrubs and trees.

May 2019 trees and shrubs in bloom

May 2019 flowers

A few notes about my monthly tables

As I made May’s tables, I thought of a few points worth mentioning here.

For many plants, I have multiple clumps in the front and back yards, and in differing degrees of sun. The plants in more sun bloom earlier that ones in more shade, which prolongs bloom times in the tables.

If plants have no pollinator value, should I bother including them? I’m going to include them in the tables anyway because I have been surprised to see pollinators visiting ‘worthless’ flowers. A few weeks ago, my son pointed out a queen bumblebee drinking nectar from periwinkle flowers. It wasn’t visiting the Merrybells, Dutchman’s breeches, or Hellebores in bloom. Maybe my patches of those native plants are still too small for them to notice.

I want to start tracking what’s going on in my front and back gardens. This information will help me ensure there’s always something in bloom for pollinators. It will also be useful for planning future changes to my garden beds. My table format is a simplified version of the Minnesota Wildflowers What’s Blooming pages.

Phenology

Have you ever heard of phenology? I hadn’t either. It basically means what happens when in nature. There’s a lot of interest in phenology now as scientists track how climate change is affecting the timing of plant and animal activity. Unfortunately, the shifts in timing are not always in sync.

I plan to participate in PlantWatch, a community science project collecting flowering dates for selected plant species. This data will be used by researchers studying climate change in Canada. Although I only have 7 of the 22 species they’re tracking, I’ll contribute what I can.

April flowers

April 2019 was quite cold and rainy. It seemed to drag on forever. Earth Day, April 22nd, fell on Easter Monday, so we all had the day off. It turned out to be the warmest day of the month, and a perfect time to watch the first bees and butterflies in our yard.

Pussy willow catkins, bulbs, and spring ephemerals appeared on cue. The pussy willow shrubs were the star attraction for pollinators. Here’s a video of the tremendous pollinator activity on my largest pussy willow; there are mining and cellophane bees, flower flies, and a few honey bees. Oddly, I have never seen a single bee on my hepatica or bloodroot.

April pollinators

I saw the first bees, and only butterflies, on Earth Day, April 22nd.

I have a lot of trouble identifying bees. My guesses for these two are based on articles on Houzz by bee expert, Heather Holm: Invite Cellophane Bees to Your Garden by Providing Patches of Bare Soil and Invite Mining Bees to Your Garden by Planting their Favourite Plants.

Work to do

It turns out that two of my earliest spring flowers are invasive, or nearly so — squill and periwinkle. The squill is easy to remove, but periwinkle is more challenging.

I actually moved squill bulbs to my pollinator garden because I thought squill and bloodroot made such a pretty combination. While it may not be on an official invasive species list for Ontario, it has spread a lot in wild spaces. Here’s an interesting article, Is Scilla siberica invasive? about squill and how plants are deemed ‘invasive’. I had an inkling that it might be after I saw a large, dense patch of it in a clearing at Mud Lake. I’m not sure what I can substitute it with that will bloom so early, at the same time as bloodroot. I’ll have to take a walk around the neighbourhood to see what other bulbs are blooming now. For ideas, I will also consult the PDF booklet Grow Me Instead, and this list of Alternative Plants for Invasive Species. These suggestions don’t always bloom at the same time though, so they won’t provide a similar flower combination.

Periwinkle is considered invasive according to Ontario’s Invading Species Awareness Program. I have successfully removed periwinkle in another part of my garden. While pulling it out, I carefully teased out the root clumps. Whenever it popped up afterward, I pinched it off. At least it is easy to spot since most other plants aren’t up yet. I will always have to battle periwinkle though because a neighbour grows it willingly.

“Plant it and they will come” is the native plant gardeners’ rallying-cry. It emphasizes how easy it is to grow native plants, and how quickly wildlife will find them. It really is that simple.

In 2017, I turned a patch of our Ottawa, Ontario front lawn into a pollinator garden. I included many native plants, as well as other pollinator-friendly flowers. Even in its first year, the garden attracted many bees, butterflies, beneficial insects, and even hummingbirds.

Pollinator populations are declining due to habitat loss, pesticides, and climate change. Urban gardens can provide new, safe habitats for pollinators in need. You can do it too! I’m happy to share with you what I’ve learned.

I’m not exaggerating when I say that creating this pollinator garden is one of the best decisions I ever made, and that it has changed my life. You can read about why and how I created my garden in a blog post I wrote for the Wild Pollinator Partnership. Perhaps you will be inspired to start your own pollinator garden.

More than a pollinator garden

Once I started growing native plants for pollinators, the plants began to attract other wildlife too. We now have a resident toad, rabbit, and chipmunk, as well as many bird visitors stopping by for food and water. Our lifeless yard has become a small, but fully-functioning ecosystem. The whole family is learning about the plants, insects, birds, and animals around us.

You can do it too!

For the first time, I really feel like I am making a difference for wildlife and for the health of our environment. It may be a small difference, but it is a tangible one. I can see right in front of me that I’m now providing food and shelter for hundreds of bees and butterflies, and dozens of birds. I would never have imagined that my new pollinator garden would be so full of life.

If more people, like you, turn some unused lawn into a native plant garden, the impact of these gardens will add up. Plant it and they will come; it really is that simple. My garden is living proof. Go ahead, you can do it too!