Cultivate a natural habitat for pollinator reproduction

Every pollinator garden should strive to provide abundant, native, and pesticide-free forage and nesting areas. 


This page shows what you can do in your pollinator garden to either create or enhance natural features to support reproduction.
Although many of the tips will benefit both, the page is divided into two parts:
⋅  information for bees, which nest
⋅  information for butterflies, which do not nest.

Bees

Did you know some of the smallest bees fly only a hundred feet between foraging and nesting sites?  This is what makes bees and wasps such unique pollinators; their foraging behaviors are directly linked to their nesting behaviors.  Unlike other pollinators that collect nectar and pollen to feed themselves, bees and wasps also forage to provide food for their brood cells (the eggs of their young).  To support these pollinators, it is necessary to provide both nesting and foraging resources within the same habitat patch.

To cultivate or retain natural nesting areas for bees, it is important to understand how they nest.  With the exception of cuckoo bees, all bees build nests where they lay their eggs. They stock their nests with a nutritious mix of pollen, nectar, and saliva before laying the eggs and then sealing the nest so the offspring remain safe.

Hover your mouse over the pictures below to see where bees may make their nests.

[Click on image for Photo Credits/Permissions]

In your pollinator garden, keep an eye out for the types of environments pictured above and do your best to protect them, as they may already be existing nesting sites. This means that it is okay for your yard to be a little less manicured than you’re used to.  Think about tree hollows, old logs, snags, piles of twigs and other garden “debris” as potential bee-friendly habitats.

To further cultivate your area to attract bees, it will be necessary to look at the two nesting categories: ground-nesting and hole-nesting.

Ground-nesters such as digger bees, bumblebees, cuckoo bees, sweat bees, and miner bees nest underground, or in the rare case of some bumblebees, slightly above ground in mulch or debris piles. Bees in this group usually scout out prime real estate on bare, sunny, sandy or loamy soil patches with little likelihood of flooding.  If you want to attract these type of bees you should:

1. Leave bare soil in between patches of vegetation.

2. Avoid using weed matting, heavy mulching or dense layers of bark chips to cover large  areas of your garden.

3. Avoid heavy tilling, flood irrigation, soil fumigation,and high-intensity grazing in bare or patchy soil areas in agricultural or mixed-use settings.

4.Leave small areas of grass clippings or heaped thatch.
This will serve a dual purpose: to provide areas for brood cells and a safe place for the overwintering of queen bumblebees.

Remember, the best and most usable pollinator gardens are those that resemble wild, natural habitats, so don’t be too neat!

Hole-nesters are bees that make nests above ground. They to can be divided into two groups:  those that nest in existing holes and those that create their own holes.

Mason bees and leafcutter bees are members of the former group.  They take advantage of holes made by other animals in dead wood. The holes can be abandoned beetle tunnels in stumps or snags, holes in trees made by woodpeckers, or tunnels in pithy, wooden plant stems created by chewing insects.

Carpenter bees are  members of the latter group. They have powerful jaws, called mandibles, which are used to excavate tunnels in wood. They prefer soft, unfinished, and unpainted wood. The following things can be done to accommodate the habitat needs of both types of above-ground nesters:

1. Recycle small pruned branches. Tie them together in a pile and place in your garden.

2. Leave hollow fallen logs and old tree stumps, as long as they do not pose danger to people or property.

3. Include plant species with pithy or hollow stems such as raspberry, blackberry, elderberry, and numerous species of forbs.

beauty in the mud
beauty in the mud (Photo credit: Flickr user sammix2008)
beauty in the mud (Photo credit: sammix2008)

4. Include leafy forage near nesting areas for leaf-cutter bees.

5. Create an area or patch where mud is available for mason bees. Mud can easily be provided by placing soil in a clay plant saucer and keeping it moist.  Mud puddles also make an excellent addition as a substrate for butterflies!

The final habitat requirement for native pollinators is a place to spend the winter.  For most bees, the nesting practices described above provide environments for both pupation and overwintering. Adult carpenter bees return to their old larval tunnels to overwinter. In contrast, female bumblebees will not hibernate in their original cells, rather the queen buries herself in soil or leaf litter.

The good news is there are no extra steps required to ensure your pollinator garden provides safe overwintering sites.  Such habitats will already be in place. Just be aware that your yard may host overwintering pollinators.

Butterflies

To attract and accommodate butterflies in your garden, you must provide nectar plants for adults, host plants for the eggs and larvae, and appropriate areas for overwintering.  Female butterflies select specific plants on which to lay their eggs.  This ensures the emerging caterpillars will have the correct food to eat.

Monarch Butterfly Laying Eggs
Monarch Butterfly Laying Eggs (Photo credit: Wikipedia)

Host plant specificity varies among  butterfly  species.  For example, the monarch butterfly only lays eggs on milkweed species, whereas the grey hairstreak butterfly is known to lay eggs on several different plant species including partridge pea, mallow, mint and oaks.

The best place to start is to research butterfly species in your area, learn their host plants, and incorporate these into your pollinator garden.

Click here to see the larval host  plants on our “top ten plants to include in an Atlanta pollinator garden”.  Click here to learn more about butterfly species known to occur in Atlanta.

Unlike bees, most butterflies have different habitat requirements in summer and winter. Species that pupate during winter do so in cocoons, underground, or in a hard chrysalis.  Plant species is not important for overwintering habitat.  Rather, it’s the physical structure of the environment that is important.  Tall grasses, bushes, trees, old fence posts, and piles of leaves and sticks will provide good overwintering sites.  Again, small amounts of general garden debris may not be desirable for a heavily manicured formal garden, but is just perfect for a pollinator garden.

A good rule of thumb is if you know that some of your species overwinter in specific areas, keep these areas undisturbed throughout the winter.