Most people picture a buzzing hive when they think of bees. But some of the hardest-working pollinators in your garden are loners—and they’re quietly doing extraordinary things.
Solitary bees don’t make honey, don’t swarm, and rarely sting, plus they pollinate with astonishing efficiency—a single female mason bee can match the pollinating power of 60 honey bees! Set up mason bees near your Spring cherry tree and you could double your fruit yield. Add leafcutter bees to your Summer garden and watch your tomatoes, melons, and zucchini thrive.
Whether you’re a beginner gardener, a backyard orchardist, or simply someone who wants to support local pollinators, building a DIY bee house is one of the most rewarding projects. Unlike honey bees, solitary bees don’t form colonies—each female nests alone, laying her eggs inside narrow tunnels she finds in dead wood or hollow stems. As tidy gardens and land clearing make these sites increasingly scarce, a bee house fills the gap, giving solitary bees the cavities they’d naturally seek and leaving you with a more productive garden in return!
Meet the Unsung Heroes of Pollination
The Pacific Northwest is home to roughly 70–75 native mason bee species and 40 leafcutter bee species. Together, they form a highly effective, long-season pollination team: mason bees emerge in early Spring and leafcutters take over in Summer, covering your garden from the first blooms all the way through August.
About Mason Bees
Orchard mason bees are Spring powerhouses—among the first bees to fly each season, emerging once temperatures clear 53°F, and working longer hours than honey bees. They’re exceptional pollinators for plums, cherries, apricots, apples, pears, blueberries, kiwis, and most nuts. The female lives about six weeks, spending them methodically filling tubes with pollen, laying eggs, and sealing each chamber with mud. A single tube holds 5–8 egg chambers. By Winter, the new bees have developed and spun cocoons to hibernate until Spring.
About Leafcutter Bees
Leafcutters take over in Summer, thriving in the high 70s°F and making them ideal pollinators for July and August crops like tomatoes, melons, zucchini, and beans. Smaller than a honey bee with distinctive black-and-yellow striping, they’re named for their tidy habit of snipping smooth semicircles from soft leaves—rose leaves are a favorite, along with lilacs and dogwoods. Those small, clean holes in your garden leaves are a sign of a healthy yard! Leafcutters cement the cuttings into egg cocoons using leaf juice and saliva, overwinter as larvae, and emerge as adults in early Summer—requiring 3–4 weeks at around 84°F to complete their transformation.
Supplies for Your DIY Solitary Bee House
Both mason bees and leafcutter bees can use the same house! Consider it like a timeshare—they do not need to be in it at the same time, but they each require different diameter nesting tubes.
- Bee house: Can be made from almost any material—wood, bamboo, terracotta, or repurposed containers—as long as it’s sturdy, weather-resistant, and fits your nesting inserts securely.
- Nesting inserts: Must be easy to remove and clean. Natural reeds, mason bee tubes, or reusable wood trays all work well. Between mason bee season (Spring) and leafcutter season (Summer), simply swap in smaller-diameter tubes. Avoid drilled wood blocks or bamboo as they can’t be opened, leaving cocoons vulnerable to predators and disease.
- Mud source: Mason bees seal each egg chamber with mud. Set out a small dish of moist clay-based mud near the house—that’s all they need!
- Mason bee cocoons: Plan for one hole per cocoon and about ten cocoons per mature blooming tree. Cocoons are available for purchase at our garden centers; we don’t typically carry leafcutter cocoons. Note that you don’t need to buy cocoons at all—bees will often find a well-placed house on their own but purchasing them ensures a faster start.
- Cocoon storage: Refrigerate mason bee cocoons until release, ideally inside a HumidiBee humidifier to prevent drying out.
Solitary Bee House Placement, Preparation & Care
1. Mount Your Bee House
Mount your bee house on a sunny wall with morning sun exposure, roughly at eye level. Choose a spot protected from wind and rain—under eaves or an overhang is ideal. Leave it in place once set; female bees need a stable environment to nest. If you’re unhappy with the location, add a second house elsewhere and let the bees show you which spot they prefer.
2. Prepare Your Surroundings
Set out a mud source nearby for mason bees, and plant non-fibrous leafy plants nearby for leafcutters to use as nesting material.
3. Create a Varied, Irregular Layout
Pull some tubes or reeds out slightly from the group and tuck sticks, twigs, or small objects between them. This “messy” look gives each bee a visual landmark to find her own hole.
4. Release Cocoons (at the Right Time)
Mason Bees: Place cocoons behind or on top of the nesting box once daytime temperatures reach 50–55°F and cherry blossoms are beginning to appear (early to mid-Spring). Consider releasing in thirds to extend your pollination window. Around mid-April, check how many holes are in use—add more tubes and trays if needed, check any unopened cocoons for viability, and keep your mud source moist. Release all remaining bees by May 1st.
Leafcutter Bees: These overwinter as larvae rather than fully developed adults, so they require a warm incubation period before they’re ready to emerge. Begin incubation in late Spring or early Summer, targeting emergence when daytime temperatures are consistently in the high 70s°F and Summer blooms are appearing. Place cocoons in a Leaf Guardian bag to protect larvae from pests. Maintain a steady 84°F with 40–90% humidity—at that temperature, expect emergence in about 23 days (at 70°F, allow 4–6 weeks). Incubation can be done indoors or in a warm sheltered outdoor spot; keep larvae out of direct sunlight.
5. Store Nesting Material & Prep for Leafcutters
By early June, most mason bees have completed their cycle. Many nesting boxes come equipped with tubes in many diameters which allows bees of many species to utilize the boxes. If your habitat space is limited, remove nesting material from the house and store it somewhere with stable ambient temperature (garage, shed, barn).
If you’d like to host leafcutter bees next, this is the perfect time to set up fresh tubes or trays in your bee house—just be sure to use a smaller diameter, as leafcutters prefer a narrower hole. If your nesting box already has vacancies, these should be sufficient for the next round of solitary bees to use the site for nesting.
6. Outdoor Winter Protection
Bees can hibernate all Winter long in the Pacific Northwest, provided the nesting box is kept in a relatively frost-free location. If the nesting box is mounted under an eave or mounted on a fence surrounded by evergreen vegetation, it will likely be protected enough from cold Winter temperatures or extreme winds and experience minimal loss or damage to cocoons. During extreme cold events, the nesting box can be removed and stored in a shed or garage and placed out again when temperatures are steadily back in the 35-degree range or above.
7. Harvest Cocoons
As an alternative to keeping your nesting box outside during the Winter, cocoons may be harvested for better protection:
Mason Bees: When Fall arrives, open your stored nesting material, separate cocoons from debris by hand, and remove any pests. Leave cocoons outside in ambient temperatures for about three weeks, then move to cold storage at 35–37°F for Winter—a refrigerator works well. Through Fall and Winter, bees quietly live off stored fat, so just keep your HumidiBee topped up with water and they’ll be ready to go again come Spring.
Leafcutter Bees: Leave leafcutter nesting material in the house through Winter—don’t harvest in Fall. Their cocoons are more delicate and not waterproof like mason bee cocoons, so they should stay protected in place until early Spring, just before incubation begins.
More Bee & Pollinator Resources
- Learn about supporting other pollinators like honey bees, butterflies, and hummingbirds in your garden over on our blog How to Create a Pollinator Garden.
- Sign up for “Bee Mail” through www.crownbees.com for reminders on critical timing and care steps, such as putting your bees out too early or too late, missing an important step, leaving your bees to fend for themselves in Summer, or forgetting to harvest your cocoons in the Fall.
- Find out more about helping pollinators at www.xerces.org.
- Join in a backyard bee count with the Great Sunflower Project at www.greatsunflower.org.
- Purchase the Gardener’s Guide to Raising Solitary, Native Bees for more detailed information.