How to attract mason bees

  • How to attract mason bees

  • How to attract mason bees

This article is part of our Organic Pest Control Series, which includes articles on attracting beneficial insects, controlling specific garden pests, and using organic pesticides.

The Mason Bee (Osmia species)

In areas where cool temperatures limit honeybee activity during the spring blooming of fruit trees and blueberries, native mason bees are the pollinators that get the job done. Smaller than honeybees with dark bodies that often have a metallic sheen, mason bees can work blossoms at lower temperatures than honeybees. In much of North America, mason bees emerge when the redbuds bloom, with populations highest during apple blossom time.

Sometimes called orchard bees or blue orchard bees, most mason bees are solitary insects that nest in holes in trees, or in hollow stems of old elderberries, brambles or similar vegetation. Mason bees are so named because they pack mud into their nests, like brick masons.

Females are motivated to collect pollen because they include a ball of pollen with each egg they pack away into a mud-lined cell. After six weeks or so of busy pollen and mud collection, adult mason bees die and there is no further activity until the following spring.

Mason Bees Are Prolific Pollinators

Adult mason bees sip nectar as they gather pollen from a wide assortment of flowers, but they prefer to find good pollen sources within 300 feet of their nests.

Up to 1,500 blossoms per day must be visited to gather enough pollen to provision the next generation, so mason bees can be phenomenally efficient pollinators of fruits. Only three female mason bees can serve the pollination needs of a mature apple tree.

How to Attract Mason Bees

Grow plants that bloom in late spring (penstemon, roses) after local fruit trees finish flowering, to extend the foraging time for mason bees. If the weather is dry, provide a shallow pan of mud near your water source. Mason bees prefer mud made from clay soil.

Most mason bees nest in holes made by woodpeckers or other insects. If your property includes woods, leave dead trees standing to accommodate this food/habitat chain. In orchards or suburban environments, mason bee populations can be doubled by using man-made nesting boxes made of wood or straw. However, some native species are rarely found in nesting boxes or tubes, and it is thought these species make nests in the ground as do many other helpful wasps and bees. If you have a spot that gets morning sun that can be kept mowed high, you have a perfect site for a native bee nesting area.

More information about mason bees is available from North Carolina State University, Washington State University, and the British Columbia Ministry of Agriculture.

There are tons of bee-supporting plants out there; so many that the choices can be overwhelming. Remember that just planting a garden (even a small one) will help the bees. It doesn’t even need specific “bee-supporting plants” because really all flowering plants are bee-supporting. However, we’ve assembled a list of the top 10 plants to include in your garden to really support your solitary bees. Along with our top ten list there are 3 simple things to consider while making your selections that will invite more bees to your garden party.

What to Consider When Choosing Plants to support Bees:

1-Pick native plants to your area. Check with your local garden center for recommendations. Stay away from exotic invasive plants (such as purple loosestrife and Japanese honey-suckle) that can crowd out more useful food sources. It is best to use plants that are suited for your zone. You can look up your zone here.

2- Avoid modern hybridized plants especially the “doubled bloom” varieties. The “old fashioned” flowers provide more nectar and pollen than the new plants bred for their bright colors and showy blossoms. Many of these modern flowers do not even produce pollen or nectar and will do little good for your pollinators. If you want to include these hybrid types just be sure there are other flowers available as a food source.

3- Use a variety of flowers to ensure there are always plants in bloom. Solitary bees are opportunistic and will utilize the flowers available. Be sure to pick plants that bloom from early spring to fall. The longer the pollination season the more bee offspring will be available for next year.

By following these general rules you’re sure to create a great garden area for your bees and other pollinators. To make your garden over the top awesome for your bees be sure to include some of our top bee-supporting flowers! Here they come (not in order of importance)….drum roll please……

You’ve probably seen them placidly buzzing around your garden in late spring. Maybe you mistook this solitary little insect for a fly.

Put away the swatter: They aren’t flies, they are bees — very helpful bees. Orchard mason bees (also called blue orchard bees, for their iridescent shine) are amazing pollinators and can dramatically increase fruit and berry yields in your backyard or orchard.

As their bigger cousins, the honeybees, struggle with mysterious hive collapse and environmental challenges, the tiny, gentle native bee is stepping up (or flying in).

While the bees are usually able to thrive on their own, many humans have started to help — to increase their numbers, improve fruit yields or just to watch them at work.

Attracting and observing mason bees is a great project to do with your kids. They don’t sting, and can easily be watched as they emerge from nests in the spring — especially if you hang a house with nesting tubes or nesting block. Kids can follow a female bee from the mud (that you’ve considerately supplied) to her nest, and learn how each bee uses pheromones to mark her personal nesting cavity, so she’ll always be able to find it.

What you need to support mason bees

1. A generous pollen source within 300 feet of your bee house.

2. A source of clay-based mud. In nature the female finds a small hole, usually in wood, lays an egg in it, then plugs it with mud. Note: They do NOT damage wood or create their own holes, they just use existing cracks and crevices.

3. A nesting place. You can let nature take its course or build simple nesting boxes by drilling a series of holes in a block of untreated wood (use a 5/16th-inch drill bit), from 3 to 5 inches deep. Or you can use a length of PVC pipe for a house, and fill it with paper or bamboo tubes (these come complete with bee cocoons at many garden centers in spring).

Hang the bee house on the south-facing side of a shed or building, where it has protection from wind and rain.

4. Most importantly, if you are going to attract mason bees, don’t use pesticides.

It’s important to clean or replace your nesting blocks, or to use new tubes every season, because of predatory mites and fungal diseases.

But if the prospect of caring for bees year-round is daunting, you can even rent them.

Bothell’s Rent Mason Bees (rentmasonbees.com) offers complete kits, ready to hang. For a small fee you can pick up bee cocoons and supplies in spring (you’ll be emailed with pickup times). After the bees have nested, you’ll be emailed that it’s time to return the bees. The folks at Rent Mason Bees clean the cocoons to remove any parasitic mites, chill them at the correct temperature and humidity for the winter, sterilize and repair the nest boxes and then let you know when and where you can pick up your bees in spring.

They are available at pickup sites all around Puget Sound.

Here’s an approximate schedule of mason bee activity:

March-April

If you’ve purchased bees at your garden center, put the tubes (which contain cocoons) out in a bee house hung in a south-facing, sheltered spot. Timing depends on the temperature, but a good guide is when your fruit trees are about 25 percent in bloom. Typically in Snohomish County, it’s mid-March.

Males will emerge first when it gets warm enough. They need to reach 80 degree to fly, but a sunny location for their house will warm them up enough even when it’s colder outside. They can be observed closely, as they are gentle and have no stinger.

Females emerge a few days or weeks later, depending on the weather. They start mating with males soon after. They can sting but are not aggressive and rarely do so unless frightened or squeezed.

Make sure you have a mud source (add clay if your soil is too sandy) near the bee house (not right under it). A shallow tray of water with stones for landing will encourage egg-laying.

Female bees lay a single egg at a time in the hole, and then add a ball of nectar and pollen — a food source for the larva. Then they plug the chamber with mud. They repeat the process for several days (one to two eggs a day) until the tube is full of eggs, each in a separate chamber with a pollen ball. The mason bee will lay the fertilized female eggs at the back of the hole and the males in the front — that’s why they emerge first.

May through late summer

Larva hatch within a few days of being laid and begin to eat the food in their chamber.

In about 10 days all the food is gone and the larva has the energy it needs to spin a cocoon and pupate in the chamber.

In mid to late June you can check that the tubes are capped with mud. That means they are filled with bee eggs.

By the end of June the eggs have all been laid and most of the females have died (kids, don’t be sad, that’s just how it works!). At that point, activity around the nest box really drops off.

Near the end of summer the bees in the nest transform into adults but stay in the cocoon. This is the safest time to move them.

By the end of August the larvae have become pupae inside the cocoons and are mature young bees. They stay dormant in this state until spring.

In late September, it’s safe to open the tubes to wash the cocoons, to remove mites. The mites are small and look like rust. Place cocoons into a paper bag or small cardboard box in an unheated garage or in a container with air holes in the refrigerator, until conditions are right for release in spring.

Humidity as well as temperature is important for the dormant bees, so if you decide to bring your bees in, check the sources below for more detailed instructions.

Everyone knows about honey bees, but it’s time we got to know some of their native counterparts, specifically, mason bees. Demarus Sandlin from Crown Bees offered to share some common misconceptions in an attempt to encourage gardeners to expand their idea of pollinators to include more than the familiar honey bee. She also talks about how to attract mason bees to your garden.

How to attract mason bees

Mason bees are a bee species you might not recognize, but they are great pollinators. Here’s a look at how native bees differ from our misconceptions. In this case, Demarus introduces us to blue orchard mason bees, Osmia lignaria.

How to attract mason bees

Six common myths about bees

Myth: Honey bees are great pollinators

Honey bees are actually not the greatest pollinators. When this bee species gathers pollen, they wet it and form packages on their hind legs. Not much pollen falls off these wet pollen packs.

Mason bees carry pollen in dry form all over their hairy bodies – these messy little flyers pollinate essentially every flower they visit. They are an efficient pollinator and just one is equal to about 100 honey bees as far as pollination goes.

Over the last 60 years, honey bees have been used as agricultural pollinators but a more sustainable practice is to support our native pollinators.

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How to attract mason bees: Provide pollen. If you want mason bees to help pollinate your vegetables, one of the best things you can do is to provide flowering plants that will attract them to your garden.

Myth: All bee species are aggressive and they all sting

Most solitary bees are not aggressive. Male mason bees do not even have stingers. Females do have stingers, but are usually busy gathering pollen and nectar for their own eggs. If a female mason bee does sting, it will feel similar to a mosquito bite.

Myth: They all make honey

Of the 20,000 species of bee in the world, only seven are honey-producing. Bumblebees make small nectar stores but they are small pots for use during brooding season.

Masons do not make honey; instead they gather pollen and nectar to feed their young. The pollen is gathered into a pea-sized ball and mixed with nectar to form a pollen loaf. An egg is laid on this loaf and the hatched larvae feed on the mixture.

How to attract mason bees

Myth: They all live in hives

Only 10% of the world bee population builds hives and supports one queen bee. Ninety percent of the native bee population are solitary, meaning that each female is a fertile queen and works hard to lay eggs AND build nests.

About 70% of native bees are ground-dwellers and around 20% live in cavities or holes. The Mason bee variety lives in holes like hollow reeds. Although they are not social, they are gregarious, which means they do not mind living near other bees.

How to attract mason bees:

A stack of nesting holes acts much like an apartment building, and each female “owns” the hole she nests within. You can attract mason bees and encourage them to move in by providing suitable nesting space.

How to attract mason bees

Myth: All bees have yellow & black stripes

Some native bee pollinators are bright green, others are full black, and some in Asia are a bright turquoise blue! Mason bees are small and metallic blue, and look a little bit like a hairy housefly. Common features among them all are eyes shaped like a pointy oval (similar to an ant), two sets of wings for a total of four wings, and thick, hairy legs. (Now you know the features to look for next time you are looking for them in your garden.)

Mason bees vs. Carpenter bees

Mason bees are not the same as Carpenter bees. Mason bees nest in ready-made holes. Carpenter bees, on the other hand, drill holes in wood. Trees, two-by-fours, decks, house siding, you name it. They prefer untreated wood, but in a pinch, they’ll even carve holes in finished wood. Carpenter bees make these holes for laying eggs, but their work can do damage. Mason bees are not the ones to blame for damaged wood.

How to attract mason bees

Myth: All bees fly great distances to gather nectar

While this may be true for honey bees that will fly up to four miles in search of nectar and pollen, most natives stay very close to their nesting sites. Masons will only travel up to 300 feet, or 100 meters, away from their nesting holes. Mason bees love early-blooming spring trees like apples and cherries.

The name mason bee comes from the bee’s nest-building behavior. The female mason bee carries clay-like mud in her jaws and uses it to build chamber walls.

How to attract mason bees:

Provide a water source. And don’t be too tidy with it. (Ducks can help with this!) Mason bees will appreciate the ready source of building materials.

To learn more about this gentle, safe, and easy-to-raise bee species, please visit Crown Bees here.

How to attract mason bees

Non-parasitized mason bee cocoons will be firm to the touch and dark grey. Cocoons that are lighter in colour and “crispy” to the touch are likely full of tiny parasitic wasps. You may even see the entry hole. One infested cocoon can contain up to 60 developing wasps! (Photo: Steph L via Flickr)

If you choose to attract mason bees to a bee home in your wild bee sanctuary, take responsibility for increasing the likelihood of healthy bees emerging in spring.

It’s a lot like washing and maintaining bird feeders, baths and houses to help keep songbirds and hummingbirds healthy. (Not sure what a mason bee is? Learn more here!)

The best time of year to harvest and clean bee cocoons is between October and December. The bees will be fully formed by then. The best time to release them is in March or April.

The goal is to reduce bee deaths and have healthy cocoons to release in spring! Cleaning cocoons keeps parasite numbers low and prevents disease spread in the colony. Washing cocoons and the bee house removes pollen mites, parasitic wasps, dermestid beetles and fungal pathogens that feed on pollen, nectar and developing bees.

Note: Unfortunately, some people have unintentionally bought poor quality bee homes when they wanted to help native mason or leafcutter bees. Check out 10 ways to see if your native bee home will help or harm bees.

How to attract mason bees

How to harvest and clean cocoons in fall

You’ll need:

  • Scrap paper or newspaper
  • Scissors
  • Chopstick/stir stick
  • Glass measuring jug
  • Room-temperature water
  • Spoon
  • Oxygen bleach (liquid)
  • Sieve
  • Paper towel or re-use tissue paper
  • Clear plastic lid
  • Flashlight
  • Jar with lid (and punched holes)
  • Small paper box and tissue paper
  • Scrub brush

1. Prepare work area

Cover your work area with scrap paper to collect debris like mud and bee poop. Remove all plastic or wood trays from the bee house.

2. Check your bee house and tubes

Look for holes in the tube and if mud at the entrance has been compromised (see 5 below). Put suspect cocoons to the side. Mark or make note of the front and back end of tubes. Females are in the deeper chambers (more than three inches from the nesting hole). Males occupy the outer chambers (emerging first in spring). It’s possible to get an idea of male to female ratio by noting their size and location in the tube. Typical ratio is 2:1 male to female.

3. Open trays and tubes

Gently open plastic trays or cut homemade paper tubes (use scissors or remove tape). For houses made with reusable paper straws try using a dowel. Carefully pry cocoons (small brown ovals between mud walls) off with a chopstick or stir stick and set them aside. Inside are fully developed hibernating bees!

4. Identify contents

Carefully separate cocoons from other contents. You may find:

  • Black: gnat-sized, parasitic chalcid wasp
  • Bright yellow: pollen mite poop or frass
  • Brown/black: poop
  • Cream: dermestid beetle larvae that eat hibernating bees
  • Crescent-shape: mummified larvae infected with deadly chalkbrood fungus (dark and abnormal looking)
  • Dark grey: cocoons (males are often smaller; females are larger)
  • Grey: mud (it can take a bee 12 mouthfuls of mud to create one cell wall!)
  • Orange or reddish “sand”: pollen mites (e.g., Chaetodactylus krombeini) that eat what the bees need
  • White: mould
  • Yellow: pollen

Check images from Crown Bees and Oregon State University to help.

5. Identify “suspicious” cocoons

Non-parasitized mason bee cocoons will be firm to the touch and dark grey. Keep these. Go back to the tubes/tray you sorted. Cocoons that are lighter in colour and “crispy” to the touch are likely full of tiny parasitic wasps. One infested cocoon can contain up to 60 developing wasps! (Many gardeners attract parasitic wasps to combat garden pests. Consider adding parasitized cocoons to your bug hotel.)

Not sure? Spread the cocoons on a clear surface (bottom of a glass jar or on a clear plastic lid). In a dark room, shine a flashlight underneath and discard those that look hollow.

6: Wash viable cocoons

Place cocoons in jug of room temperature water. (They’re buoyant and water repellent.)

Agitate by stirring with your hand to loosen stuck-on dirt, feces and mites. Debris will fall to the bottom. Scoop cocoons with a sieve and place in a bowl or pail of five per cent oxygen bleach solution. Soak for five to 15 minutes, stir and then scoop them up with the sieve. Rinse them well to remove all traces of oxygen bleach. Do not use soap or detergent — that will kill the bees! Place washed bees on a cloth or paper towel to dry for about an hour.

7. Bee cocoon winter storage

Add clean cocoons to a small paper box wrapped with paper towel. Place the box inside a plastic yogurt container or glass jar — whatever will keep rodents and moisture out. Punch air holes in the lid. Store your container in the fridge at 0 to 5 C (60 to 70 per cent humidity), in an unheated garage or outside. Ants, woodpeckers, squirrels, racoons and bears can wipe out mason bee colonies. They’re more likely to survive the winter if you eliminate this risk!

8. Clean the house

Bees prefer clean nests! Soak trays in soapy water, scrub them with a brush and rinse thoroughly. Soak again in a five per cent liquid oxygen bleach solution to kill bacteria and fungi. Spray the entire bee house with five per cent liquid oxygen bleach, rinse well and dry. Store the house until next spring before you hang it and release cocoons.

Reading Time: 8 minutes

  • By: Robert Vinson

As the weather warms and gardeners around the country are ready to sow spring seeds for plants and flowers, it comes to no surprise that some gardening enthusiasts still want to take their gardening to the next level. From trying to raise more finicky plants to expand the size of their garden flowers, gardeners who wish to challenge themselves and improve their garden should consider investing in a garden pollinator for this spring.

A pollinator is an essential insect that assists in pollinating your garden flowers. If you own any fruit trees or an orchard, pollinators are essential for the production of fruit—every year about 1.8 million honey bees actively pollinate America’s orchards and farms.

You may think that a homeowner-turned-gardener doesn’t necessarily need millions of honeybees, much less even 10 honeybees. The question is, are they even worth the effort and beneficial to your plants and flowers? Luckily for amateur gardeners, there is a bee that doesn’t sting, isn’t high maintenance, and is just as effective at pollinating in comparison to your average honeybee. One species of bee, now becoming more popular with even beginning gardeners, are mortar bees, also called mason bees.

NatureZedge understands that several doubts may still run through your mind. Won’t the bees sting? Is it easy to house mason bees? Is it even worth pollinating with mason bees for flowers? How effective are bees when it comes to pollinating?

In this guide, we cover the most basic questions about bee pollination and help you consider the pros as well as the cons of raising one of America’s most effective pollinators in nature.

There are tons of bee-supporting plants out there; so many that the choices can be overwhelming. Remember that just planting a garden (even a small one) will help the bees. It doesn’t even need specific “bee-supporting plants” because really all flowering plants are bee-supporting. However, we’ve assembled a list of the top 10 plants to include in your garden to really support your solitary bees. Along with our top ten list there are 3 simple things to consider while making your selections that will invite more bees to your garden party.

What to Consider When Choosing Plants to support Bees:

1-Pick native plants to your area. Check with your local garden center for recommendations. Stay away from exotic invasive plants (such as purple loosestrife and Japanese honey-suckle) that can crowd out more useful food sources. It is best to use plants that are suited for your zone. You can look up your zone here.

2- Avoid modern hybridized plants especially the “doubled bloom” varieties. The “old fashioned” flowers provide more nectar and pollen than the new plants bred for their bright colors and showy blossoms. Many of these modern flowers do not even produce pollen or nectar and will do little good for your pollinators. If you want to include these hybrid types just be sure there are other flowers available as a food source.

3- Use a variety of flowers to ensure there are always plants in bloom. Solitary bees are opportunistic and will utilize the flowers available. Be sure to pick plants that bloom from early spring to fall. The longer the pollination season the more bee offspring will be available for next year.

By following these general rules you’re sure to create a great garden area for your bees and other pollinators. To make your garden over the top awesome for your bees be sure to include some of our top bee-supporting flowers! Here they come (not in order of importance)….drum roll please……

By: Chelsea Hoffman

21 September, 2017

Mason bees are unsocial bees that burrow in the ground and in rotting wood. They are a bit smaller than a honeybee and do not make honey. Because they do not make honey, mason bees prove to be docile enough to only sting when stepped on or provoked. Mason bees provide easy pollination for your home garden and landscape plants from fruits and flowers to vegetables and herb gardens. Several flowers benefit from being pollinated by mason bees, especially flowers of yellow, blue and purple tones. Mason bees, like all other bees, cannot see certain colors–red in particular.

Acacia

Acacia flowers are bright yellow and bloom in puffy clusters from the tree of the same name. Mason bees, as well as many other types of flying pollinators, see yellow clearly. This makes acacia flowers extra alluring to them. Acacia trees are considered large weeds or invasive species in many parts of the United States, especially the Southeast; however, having one nearby attracts mason bees for pollinating other plants on your property.

  • Mason bees are unsocial bees that burrow in the ground and in rotting wood.
  • Several flowers benefit from being pollinated by mason bees, especially flowers of yellow, blue and purple tones.

Canterbury Bells

The delicate, royal-purple blossoms of the Canterbury bellflower attracts a variety of pollinating creatures, including mason bees. Also known as bellflower, it thrives in loamy, dark soil in temperate forest areas, naturally. Growing this flower in your garden to attract mason bees for pollination requires partial shade and plenty of mulch to retain moisture. The scent of the bellflower is sweet, floral and reminiscent of lily of the valley or snapdragon. This sweet, floral scent attracts the mason bees that are after the delicious nectar.

Daisies

Several thousands of species make up this sunflower-related flower family, making up the largest family of vascular plants. Daisies vary in shape, size, color, texture and scent greatly from species to species, but all of them require the pollination of insects and birds. Attracting mason bees with daisies proves to be a simplistic task for even the novice gardener, as these flowers grow adequately during spring in temperate climates. Like the sunflower, daisies don’t require super moist soil conditions, in fact they prefer infrequent drinks of water and a layer of mulch to preserve the soil’s moisture.

  • The delicate, royal-purple blossoms of the Canterbury bellflower attracts a variety of pollinating creatures, including mason bees.
  • Like the sunflower, daisies don’t require super moist soil conditions, in fact they prefer infrequent drinks of water and a layer of mulch to preserve the soil’s moisture.

Attracting mason bees with daisies only requires that you grow appropriate colors–yellow, blue, purple and several varieties of these color tones.

Cross-Pollination

Mason bees offer a boost in cross-pollination of fruit and flower plants, commonly in garden settings. Some of the fruit plants that benefit from mason bee pollination include apples, pears, mulberry, blackberries and raspberries. Mason bees are beneficial to any plant that requires a living pollinator. Cross-pollinating fruits allows you to create different fruits. For example, apples and pears cross-pollinate commonly. This creates a juicier apple.