What’s your advice on creating native pollinator houses for mason bees, butterflies and ladybugs?


I am writing an article for my garden club about creating native pollinator houses for mason bees, butterflies, and ladybugs. I am looking for do’s and don’ts, materials to use, and where to position it in the yard/garden. Also, care and maintenance.


Marjorie Peronto, Extension Educator, Hancock County

The following UMaine Extension bulletin will give you all you need to know about making conservation bee houses: Understanding Native Bees, The Great Pollinators: Enhancing Their Habitat in Maine.  Below is an excerpt that describes proper placement of bee nesting houses:

  • Mid-March to late April is the best time to set the houses if you want to attract Osmia, because they emerge and start searching for nest sites in May. You may set the houses as late as mid-September and get some nesting in warm autumns.
  • East-southeast is the preferred exposure for the front of the house and the tunnel entrances. Hang the houses at a slight downward angle to prevent rain from flooding the tunnels.
  • The houses should be 3 to 5 1/2 feet above the ground, so snow will not cover the blocks in winter. This avoids prolonged wetness and possible growth of fungi. Stakes are recommended. Research shows more bee nests are made in bee houses that are on stakes. Also, other insects and spiders make fewer nests in wooden bee nesting houses on stakes. If you use stakes, the bottom of the bee house should be 3 feet above the ground. The houses can also be placed on fence posts or the sides of outbuildings, with the bottom of the bee houses at least 3 feet above the ground.
  • Native bees do not fly great distances, so the houses need to be relatively close to suitable leaf or soil material for their nests and within 50 yards of their nectar and pollen flowers.
  • Nesting houses on stakes can be placed around the yard or garden, from 3 to 10 feet apart. If you are using them in a large-scale agricultural or orchard setting, they should face into the field or orchard and be spaced 10 to 25 feet apart.

In terms of butterfly shelters, it is much more important to provide a variety of host plants for the butterfly larvae and adults to feed on, and a source of water, than it is to provide a butterfly box. See this UMaine Extension bulletin Landscaping for Butterflies in Maine for a thorough explanation. Below is an excerpt from the bulletin about providing cover for butterflies.

Overwintering butterflies need cover. This shelter may already be present in the habitat. Since species overwinter in any of the four developmental stages, adequate cover is essential for survival.

Butterflies overwintering in the adult stage may use the peeling bark on trees, perennial plants, and old logs or fences. Old sheds, barns or houses also provide overwintering sites. Butterfly hibernation boxes may attract wasp colonies, and not many of Maine’s butterfly species would use such a box.

Regarding ladybug shelters, I have not found any research supporting their effectiveness. If the garden has a balanced and diverse ecosystem that includes food that ladybugs enjoy (aphids, mealybugs, and mites), and insecticides are not used, it will attract and sustain a lady beetle population. See the following UMaine Extension bulletin for more information on attracting Beneficial Insects and Spiders in Your Maine Backyard.