Making and installing artificial nesting structures in your pollinator garden can be simple, cheap and fun!
Artificial nesting elements in your pollinator garden will give a habitat alternative for your visitors. These structures do well in smaller gardens where natural site nesting may not be available. As a compliment to existing natural areas in larger gardens, and as an important part of the infrastructure on large commercial farms. They can be structures that are created specifically for nesting, or ones that are created to aid pollinators in other ways such as shelter.
Underground nesting bees and aboveground nesting bees vary greatly in their needs for nesting sites and shelter.
With the exception of the alkali bee, very little is understood about the specific nesting needs of underground bees.The best way to provide for our underground nesters is to conserve natural areas. See here for more ideas on how to cultivate a desirable natural area for ground nesting bees in your pollinator garden.
For above ground nesters artificial structures are great! They are also cheap, fun and easy to make!!
When deciding on on what type of structure to put in your garden start by considering what species of bee you see frequently in your garden and expand from there. The more varied your habitat selection the more varied your pollinator population will be.
Hover your mouse over the pictures below to see some different examples.
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1. Bee block or Stump block
Bee blocks and stump blocks are the more popular choices amongst avid pollinator gardeners, as they are attractive, require minimal assembly, and they can also be used over and over again if designed and used properly. Use the same guide for both. A stump block is the same as a bee block it simply uses a tree stump rather than a prepared piece of lumber.
general design and tips
– Always use preservative free lumber for a bee block
-Drill nesting holes in varying but appropriate sizes and depths
-Ensure holes are only open on one end, use a backing board if holes are accidentally drilled all the way through
-Make sure the tunnels are as smooth as possible, using sharper drill bits will help keep holes smooth
– Attaching a roof will provide additional shelter for your nesting bees
-Attaching it to a permanent structure, will help for stability
-Place your structure in a bright but protected location. Direct sunshine in the morning will provide bees with warm temperatures so they can prepare for flight. So if possible place nests facing east, allowing the morning sun to fall on the entrance. Direct sunlight later in the day can be detrimental to the brood cells
– On one side of a 4x 4 lumber drill nesting holes (between 3/32 and 3/8 inch in diameter)
-Holes 1/4 inch or less in diameter should be 3-5 inches long
-Holes larger than 1/4 inch in diameter should be 5-6 inches long
– To control pests and diseases you can insert paper straws made from rolled wax or parchment paper inside each hole, which can then be removed at the end of each season and stored in a cool dry place and then placed outside the following spring near the structure where you have inserted new straws in the holes for the coming spring.
-Once the paper straws have been removed blocks can be also sanitized-with bleach or changed out every two to three growing seasons.
Xerces.org provides a great PDF here for more details
2. Stem bundles
Stem bundles are the most low maintenance, easiest, and cheapest structures to make. They are the most “natural” artificial structures you will find in a pollinator garden. Stem bundles can be created from stems or plants like bamboo or created from pithy woody plants where the inner, softer, core can be pushed or drilled out.
-Use bamboo canes, Festuca stems, pithy or woody stems, elderberry stems and some types of Sumacs will also work
-Cut the stems and align into a bundle.
-tie with twine, wire etc
-if your stems have two holes you will need to plug one end with some inert plant material, clay, or other organic matter
– An alternative to plugging the ends of the stems is inserting the stems into some kind of structure like a pot, coffee can, oatmeal can, PVC piping etc
-affix to a structure or hang from a tree.
These can often be made very cheaply or even for free by using materials in and around your garden and kitchen. They should be disposed of routinely to stop the spread of disease as they do not utilise paper straws like the bee block
Unlike for bees, the artificial elements in a butterfly garden are designed more for the adult population. They are less about providing nesting structures for eggs and juveniles and more about basking, sheltering and providing water for winged adults.
Butterflies enjoy basking, to warm their bodies and wings for flying. Perching or basking on leaves and flowers is common practice, and the natural alternative. You can however introduce some artificial elements to encourage and aid this behavior. Installation of natural rocks or landscaping rock, or building/keeping cement paths or stepping stones in warm sunny areas both provide an artificial substrate for butterflies.
Male butterflies enjoy another interesting behavior called “puddling”. The butterflies will feed off a substrate that fills a nutritional need that nectar alone does not fill. Naturally this would occur at mud puddles, sand areas or even on piles of dung. These substrates provide the males with important minerals and salts, and also as a water source.
This can be provided artificially with the use of soil, sand and a small water bowl, terracotta pot or pie plate. By digging a small hole and submerging the item in the ground you can simulate a “ground” puddle. However it can be done in a standing bird bath as well , the buried method will however decrease evaporation, which may be helpful especially in summer when “puddles” will need to be checked daily for moisture levels
Filling the container with sand and enough water to make it moist, you can then add soil from the garden, or even periodically a piece of over ripe or rotting fruit. Most references also suggest adding salt, and manure, and to use if possible rainwater or spring water.
And happy butterfly watching in your pollinator garden!