a wildflower experiment

I got tired of trying to grow vegetables in my backyard garden space year after year, only to have them wilt with insect infestations, or get some virus that turned the leaves brown.  And finally at summer’s end near optimal harvest time, the garden was shaded by 2 p.m., because the maximum altitude of the sun’s arc in the sky in late August was below the tops of the trees.

So I converted my vegetable garden to a wildflower garden, with a wildflower mix from a company that promised lots of native plants from my region.  I dispersed the seed generously, watered it faithfully, and waited for weeks while it looked like I was growing nothing but weeds.  As an added bonus, I thought a bevy of flowers would attract more butterflies and bees to my backyard (which is what the wildflower packet promised).

Finally, the wildflower seed mix is starting to bloom behind the giant hyssop.

It’s a lush mix of quite a variety of plants, and there probably are a good number of my native weeds  in there too.

But unfortunately, I don’t recognize many of the flowers in this mix, which leads me to wonder if they are really from this region of the country.  For example, a few  California Poppies have appeared, and I’m sure they are not native to MN.

I would love to see golden poppies every year in my garden, but I doubt they can withstand the Minnesota winter.

They are quite pretty, but I’m disappointed that these flowers seem to be non-natives that will not attract the insects that my bird friends depend on during the summer.

What is this? It’s like nothing I’ve seen around here before.

Or this? A green sweat bee made a brief stop on this flower, looking for pollen perhaps.

What might this be, some kind of pink wallflower relative?

Or these, pretty little blue and white flowers? No insects anywhere around them.

I’m going to call this a failed experiment, an important failure because it highlights something that should be an on-going concern of all avid gardeners.  And that is this:  if we continue to replace the native vegetation in our yards with non-native species, insects that depend on native perennial and annual vegetation will face a food desert.  They don’t have the biochemistry to cope with the plant defenses of introduced non-natives, so they produce fewer or no offspring in a garden of non-native plants.  And the birds that depend on those insects to feed their own young similarly suffer the consequences of the food desert.

So, plant more native species and keep those insects happy!

Monarch butterflies love our native Swamp Milkweed for its nectar as well as a source of food for their larvae.

Exploring Maplewood state park

We made a brief trip up north over the July 4 holiday to lovely Maplewood state park, about a 3-hour drive northwest of the Twin Cities.  Lakes, trails, great campsites, rental canoes and kayaks available, swimming beach, wildlife, and more.  What a beautiful place, and it must be even more so in the fall, when the maple-basswood forest has turned gold and red.

The view of upper and lower Lake Lida from Hallaway Hill must be spectacular in the fall.  Driving the man-made causeway west takes you out of the park.

The sumac was in full bloom, and honeybees were busy pollinating. In the fall, red plumes of sumac seeds will light up this hillside.

At the top of Hallaway Hill, we happened to be standing at the intersection of the territories of three Yellow Warbler males. If one male got too close to another male’s boundary, a brief aerial scuffle between them ensued. One of the resident males checked us out.

A pair of Trumpeter Swans fed on submerged vegetation on one of the lakes in the park.

Summer blooms

Finally, the flowers have begun to make an appearance after a long, cool spring.  It’s past mid-summer, but the peonies have just finished (very late) and the summer bloomers are finally budding out.

Black-eyed Susan flowers are just barely open.

The common milkweed flowers fill the air with their perfume, but these were some of the very few open, and no bees were buzzing around the plants.

Monarch butterflies should enjoy this large patch of milkweed when the flowers finally open.

A milkweed beetle has found the plants, though. They are brightly colored as a warning to predators that they are full of the milkweed’s poisonous chemicals.

The bright orange flowers of butterfly weed should attract pollinators as well.

Blue Flag Iris was blooming in the cattail marsh, where its brilliant blue-violet flowers stand out in all the green. It seems to attract more flies than bees today, probably some species of hover fly that lands on those guide stripes on the petal and walk right into the inner chamber for their nectar reward.

A young painted turtle, perhaps hatched out last summer, meandered slowly through the marsh, nibbling along its way.

Ah, summer, you’re much too short, but come with such beauty.

the Margined Calligrapher

With a fancy name like Margined Calligrapher, you would never guess I was talking about a little flower fly, less than a half inch long.  But this minute insect is one of the most numerous ones in your garden right now.

Minuscule flower flies are dwarfed by even the tiny fleabane flowers whose pollen they may be consuming.

The “margined” part of its name derives from the yellow line that outlines the pattern on its abdomen.  This tiny female, identified by the gap between her eyes, is feeding on peony pollen.

Flower flies derive their name from their ubiquitous presence on flower heads as the adults seek nectar and pollen, but they are also called hover flies for their habit of hovering in mid-air, or Syrphid flies because they belong to that large subfamily.

A male calligrapher fly, identified by eyes adjacent to one another, pauses on a peony petal, perhaps searching for a female.

Their yellow and black coloration mimics that of bees, and perhaps they get some protection from predation from that mimicry, but they are far smaller than even the smallest honeybees, they have only one pair of wings, not two as all bees do, and they have short, stubby antennae, again unlike the longer ropey antennae of bees.

It’s mating time for these flies which have recently emerged from a long winter hibernation as adults or mature larvae. Females will lay a single egg on leaves of a plant that is infested with aphids, scale insects, or thrips which the larvae will then consume as they grow.

Although the eye colors of the two sexes look different in the photo, they really aren’t. Compare the male (on top) eye color in this photo to the one above.

Syrphid larva consuming an aphid. Photo from Ohioline.osu.edu, by David Cappaert.

So, not only do adult flower flies perform a pollinating service for the flowers in your garden, their carnivorous larvae perform a check on the pests (like aphids) that attack your garden plants!

This particular species of flower fly, Toxomerus marginatus, can be found almost everywhere in the U.S. except mountainous regions and Alaska, and has even made it to Hawaii.  There are numerous Toxomerus species, each with a distinctive pattern of yellow and black on the abdomen, so if you see these bee mimics in your garden and wonder what they are, here’s a handy reference page (with photos) of some of the more common U.S. species,

Eastern Calligrapher, from iNaturalist.org

https://www.inaturalist.org/posts/14985-identifying-toxomerus-hoverflies

Ants on the move

Whether it’s spring house cleaning or just colonizing new territory, the ants in my back yard are on the move.  After laying waste to large patches of lawn last summer…

Bare areas are evidence of ant nest destruction of back yard lawn in multiple locations.  The camera bag is a reference for size of old nests.

they have relocated to a shady hillside to do their nest building this summer, with predictable effects on the green sward I have been trying to cultivate.

Newly constructed ant nest on a hillside has multiple entrances to tunnels being dug out by the industrious swarm.

It’s fascinating to watch while minuscule creatures continuously bring up chunks of dirt and wood as they excavate.  I can only imagine how far into the hillside these tunnels go.

Black garden ant carrying a chunk of wood.  The ants are about 1/4 inch long.

These garden ants specialize in colonizing turf, leaving a small mounds of excavated dirt over the grass which then dies.  They consume seeds, grass roots, soil insects, nectar, fungi, and probably parts of our houses.

Some ants carry small pebbles…

and some carry relatively large boulders, probably up a long narrow tunnel to the surface where it is deposited right outside the hole.

Workers may be different sizes, but they do the same work, hour after hour, day after day without stopping.

Workers are essential to the health and maintenance of the nest, but their lifespan of weeks to months may be determined by food abundance.  In contrast queens can live for years, laying thousands of eggs over their lifetime.

It is truly impressive how much ants can excavate and how much they can carry, to say nothing of the organization it takes to perform such whole-scale nest engineering.  The wonders of the “hive mind” convert single individuals into a super-organism to build an elaborate system of tunnels and side chambers that ultimately forms a highly integrated city.

To demonstrate how complex the construction of an ant nest can be, a mammoth-sized leaf cutter ant nest was infiltrated with 10 tons of cement and excavated in Brazil. Scientists estimated that the millions of ants in the nest moved 40 tons of dirt in an area of 500 square feet that was excavated to a depth of 26 feet below the surface, as the video below shows.

the color Purple

As I look around at flower gardens in my backyard and in my neighborhood, I see a lot of purple.  Where the first flowers of spring seemed to be largely pink in color, the first flowers of summer seem to be mostly purple, a color that is not all that common in plants.  Why so much purple, and why now?

The intensely violet color of spiderwort flowers is on one end of the purple spectrum.

False Indigo flowers are another example of intensely dark purple color.

Purple is for the bees, and especially the solitary bees which are the most abundant and hearty pollinators we see in cool spring and early summer weather, before honeybees and butterflies have become active.  Bee eyes can detect light wavelengths in the ultraviolet part of the spectrum, and it seems that plants have adapted their floral displays to guide the bees right to the places on the flower where their search for nectar or pollen will do the flower the most good (i.e., pollination).

Streaks on the landing platform petal of the iris are probably visible to bees in the ultra-violet range.

One study with bumblebees in Germany showed that naive bees were highly attracted to flowers in the ultra-violet to blue range of wavelengths, and those flowers tended to produce more nectar or nectar with higher sugar concentrations than flowers of other colors.  Purple flowers that attract solitary bees tend to have the highest sugar concentration in their nectar (20-50% sugar), compared to yellow and red hummingbird and butterfly flowers that average around 20-22% sugar in the nectar.

The bell flower petals look homogeneously lilac to our eyes, but what do they look like to bees?

The variation in “purple-ness” of early summer flowers is due to the proportion of anthocyanin pigment in the flower in response to the pH of the soil environment.  In the presence of acid (or hydrogen ion), the pigment is red (or pink), whereas in the presence of nitrogen base the pigment is blue, and in the presence of aluminum, it is violet.   So, you can change the colors of your hydrangea or forget-me-nots by what you put in their soil.

Magenta-colored clematis flowers are the result of a redder expression of anthocyanin in a more acid cellular environment.

Flowers of this penstemon are pink-purple, based on the reaction of the anthocyanin in a more acid pH.

Bachelor’s Buttons, native of Europe, grows best in basic soils, which accounts for its deep blue color, and the bees seem to love it.

Purple is a coveted color in the garden, because of its rarity, and the ephemeral nature of purple flowers.  Looking back in our own history, we find that limited resources and the labor-intensive process used to create the color purple made it an expensive luxury, indulged in only by the most wealthy or by royalty.  Regardless of expense, its calming (blue overtones), yet energizing (red hues) make purple a favorite color.

the nectar thief

Each year, the Ohio Buckeye tree outside my porch window puts out a prodigious number of flower spikes, which reliably attract a few pollinators and one clever nectar thief.

Pollination of these flowers is sufficient for the tree to produce copious quantities of nuts, which are harvested by the squirrels in the fall.

Hummingbirds, bumblebees, and orioles visit the Buckeye tree in the spring, along with a horde of Tennessee warblers.

Tennessee Warblers arrive just as the Buckeye tree is in full flower. How do they manage to time it just right?

Tennessee Warblers really have nothing to do with the state of Tennessee, but do migrate through there, where they were first seen and named way back in 1811.  Like many small insectivores they spend the winter in the tropics, eating insects and nectar, and breed in the Canadian spruce forests where they specialize on spruce budworm and are critical to controlling outbreaks of the moth there.

Though they do visit flowers to consume nectar, they do not perform much of a pollination service for the plants, because they use their sharp beaks to pierce the flower at its base to get at the nectar at the bottom of the flower tube, thus avoiding the pollen on the anthers sticking far out of the flower.

Note where the beak is positioned to the side of the flower at its base. Pollen might inadvertently stick to the bird’s head or breast as it bumps into the anthers, but it might be hit or miss in depositing the pollen on the stigma of another flower.

Their beak is slightly open as if they are biting the flower to open a small hole in its base.

They only visit for a few days each spring, so I guess this must be the peak of their migration through MN this year.  You can see a light dusting of pollen on this bird’s neck and breast.

The sugars in the nectar will be metabolized and stored as fat and should provide these tiny little birds (about 2/3 the size of a chickadee) with the fuel they need to get to the Canadian spruce forest to breed.

(these photos shot with the Sony RX10 iii bridge camera through my porch window — what an amazing little camera!)

Bees and blossoms

Spring is in full swing here in northern California, and I was glad to see so many honeybees out performing their pollinating service.  In fact, there were many more honeybees here than I typically see on the flowers in streetside gardens at home. Hmmmm…wonder what that means?

honeybee on Ceanothus (California lilac)

Honeybees swarmed the tinybflowers of California lilac (Ceanothus species)

honeybee on Ceanothus (California lilac)

They were probably collecting pollen from this plant (rather than nectar).  Look at those full pollen baskets on the rear appendages.

Honeybee pollination

Twin flowers of this mint species offer nectar at the bottom of a deep floral tube, causing the bee to pick up pollen on its back as they brush by the anthers.

Honeybee pollination

Better view of the plant-pollinator geometry that ensures the bee does its job for the flower while getting its reward. Bees typically spent several seconds on each flower, so either the nectar was hard to get to, or there was a lot of it (probably the former).

Honeybee pollination

Bright purple modified leaves at the top of the flower stem attract bees to this fragrant mint. The tiny, purple-black flowers stud the sides of a thick floral stem.

Purple sage garden plant

I think this might be Spanish Lavender, which looks nothing like MN lavender.  It’s highly aromatic, like other lavenders, though.

California is experiencing a mega-bloom after all the recent winter rain, so I hope I will see a lot more of these plant-pollinator interactions in the next few days.

the beginning of the end…of summer

It’s down to the asters and goldenrods, among the last of the blooms for pollinators to visit before it’s too cold to visit anything.

Bumblebees sleeping in asters

A couple of very cold bumblebees must have spent the night in these asters. They were pretty comatose on this chilly morning.

Hoverflies on goldenrod

The yellow jacket mimicry of these very large hoverflies was so good, I almost walked away from this Stiff Goldenrod plant to avoid them.

Bumble bees on showy goldenrod

Later in the day, a hoard of bumblebees attacked the few remaining flowering stems of Showy Goldenrod. It’s a last chance to harvest nectar and pollen to store away for the winter.

All this work, and then what happens to these insects?

The bumblebee queen who founded her colony in the spring (the old queen) and all of the workers she produced will likely die in the first freezing weather of the winter.  All their work over the summer and fall was to ensure that new queens would be born and survive the winter to found new colonies the following spring.  New queens hatched during the summer feed voraciously on nectar and pollen in the fall to lay down fat stores that will carry them through the winter in their underground nest.

Bumblebees on dahlias

Dahlias keep producing their glorious blooms well into the fall until the first hard frost, another good source of nutrition for young queens.

Hoverflies (depending on the species) might overwinter as adults or as late-stage, fully grown larvae, by taking shelter in protected nooks and crannies of  tree roots or bark.  In Minnesota, they will have to withstand freezing solid, as temperatures drop well below zero.  Individuals that overwinter as adults (probably females) are the ones we see flying around in the spring looking for aphid-infested plants on which to lay their eggs before they die.  When the larvae hatch, they have a food source waiting for them. A second wave of hoverflies join the party after warmer temperatures have spurred them through the pupal stage to emerge as adults.

Hoverfly on New England aster

Hoverflies slurp up nectar from fall flowers to build up their fat reserves. Some of the fat will be used to produce a glycerol anti-freeze compound so that their cells can tolerate freezing without damage from ice crystal formation.

Beautiful, but deceitful and poisonous!

What is beautiful, but deceitful and poisonous?  This blog usually focuses on things biological, so it must be an animal or a plant, and perhaps it could be either.  In this case it is the oleander shrub that fits that description.

Nerium oleander flowers

Beautiful pink flowers of the highly poisonous oleander 

Oleander is such a popular addition to roadside plantings and gardens that it now occurs world-wide in warm, wet Mediterranean type climates where its long-lasting profusion of white, pink, or red flowers brighten up the landscape.  It is remarkably drought-tolerant and protects itself from being munched by herbivores by sequestering toxic cardiac glycosides in its tissues, from its roots to the tips of its leaves.  No wonder it’s the dominant plant along freeways in California.

Large milkweed bug on Nerium oleander flowers

An indicator of oleander’s toxicity is the presence of insects, like the large milkweed bug, with warning coloration feeding on flower parts and seeds.

Oleander is, in fact, one of the more poisonous plants, but mammals, especially humans seem to be more sensitive to its toxins than birds.  However, folk tales about drifters during the Dust Bowl years dying from having stirred their stew with oleander twigs are probably false.

Clearly, oleander is beautiful and poisonous, but what about being deceitful?  How can a plant be deceitful?

Nerium oleander flowers

Oleander flowers are brightly colored, sometimes fragrant, with a central opening meant to entice pollinators to explore.

But oleander flowers produce no nectar, and thus there is no reward for pollinators to keep exploring the profusion of flowers on the plant.  It’s false advertising and deceptive on the part of the plant.  But does it work, that is, does enough pollination occur to allow seeds to be produced?

flowers and seed pods of Nerium oleander

How many flowers with no nectar reward will a pollinator visit before it gives up and moves on?

Apparently, insects that pollinated this oleander explored many of the flowers in a cluster, moving enough pollen to produce several seed pods.  But the number of seed pods on the entire plant is scanty.

flowers and seed pods of Nerium oleander

Only a single pod was produced in this group of flowers

The only good news for bee pollinators is that the lack of nectar in the flowers means they would not contaminate their honey with cardiac glycoside poisons.