Managing your Native Landscape to Support Pollinators

Green Sweat BeeWe can all do more (or less) to manage our landscapes for pollinators. Resist the urge to clean up your landscape; instead, leave natural items such as plant stems, logs, dead trees and leaves. Pollinators need undisturbed, pesticide-free, habitat-rich, plant diverse landscapes in order to thrive.

Here are some ways we can all improve pollinator habitat in our own yards:

A standing dead tree provides nesting sites for cavity-nesting pollinators including bees, wasps and beetles.

A standing dead tree provides nesting sites for cavity-nesting pollinators including bees, wasps and beetles.

Nesting Habitat

CAVITY-NESTING POLLINATORS
Approximately thirty percent of bees and some wasps nest in cavities, usually preexisting cavities. Small and large carpenter bees will excavate their own cavities in wood or plant stems. Most pollinators seek out existing cavities. Cavity-nesting sites can occur in plant stems, holes in wood such as standing dead trees or holes in rocks.

 

 

A leafcutter bee, Megachile sp. carries a piece of a leaf into its nest in a rock cavity.

A leafcutter bee, Megachile sp. carries a piece of a leaf into its nest in a rock cavity.

Provide cavity-nesting sites for pollinators by:

Leaving standing dead trees (snags) in the landscape
Leaving or adding downed logs (nurse logs) lying on the ground
Leaving perennial stems standing for the winter to protect exisiting cavity-nesting pollinators
Carefully cutting perennial stems in large pieces and laying them on the ground. You can also poke one end of the cut stem into the ground in late spring to create a nesting site.
Adding or leaving rocks with holes for nesting cavities

An aggregation of cellophane bee nests (Colletes spp.) on a sandy slope.

An aggregation of cellophane bee nests (Colletes spp.) on a sandy slope.

GROUND-NESTING POLLINATORS
The remaining seventy percent of bees nest in the ground, typically excavating nests in bare soil or sparsely vegetated places under plants. No, these are not the same nests as the aggressive, ground-nesting yellowjacket wasps that nest in colonies. Native ground-nesting bees do not aggressively defend their nests because the majority has just one solitary female who is excavating and provisioning the nest. All ground nests are excavated by females, preferring sandy, loose, well-drained soils. Many ground-nesting bee nests resemble ant hills with excavated soil piled around the nest entrance. Ground-nesting bees often nest in aggregations with many nest entrances clustered together.

Bumble bee queens typically choose a nest site below ground, often in abandoned rodent holes.

Bumble bee queens typically choose a nest site below ground, often in abandoned rodent holes.

Provide and protect ground-nesting sites for pollinators by:

Preventing soil disturbance – no tilling or soil grading
Preventing soil compaction – no heavy equipment or foot traffic near nesting sites
Leaving areas of bare soil, especially on slopes/banks

A decaying log and leaf litter: two nesting/overwintering sites for pollinators.

A decaying log and leaf litter: two nesting/overwintering sites for pollinators.

OVERWINTERING SITES
Butterflies, moths, beetles, flies, bees and wasps overwinter in various locations in our landscapes. Besides the cavities and ground nests above, leaf litter is one of the most important places that pollinators seek out refuge. Butterflies and moths use leaf litter as protection for various stages of their life cycles including as adults, pupae or larvae. Moth larvae frequently spin cocoons in late fall to overwinter in leaf litter on the ground near their host plants. Remember to leave leaf litter in your landscape!

Foraging Resources

Use a variety of flower colors and forms.

Use a variety of flower colors and forms.

Continuous Succession of Flowering Plants
Pollinators need a continuous succession of flowering plants from spring through fall. To achieve this, evaluate your landscape to determine if you are missing some flowering plants for a particular part of the season and plant to fill those gaps.

Diversity of Native Plants
Use a diversity of native plants with different flower forms and floral resources so all pollinators can access resources. Include butterfly & moth larval host plants in your plantings.

Water
Provide a shallow source of water and refresh every 5-7 days (to kill mosquito larvae and prevent disease).

 

Plant Selection & Placement

Many of the same plant clustered together makes foraging more efficient for pollinators.

Many of the same plant clustered together makes foraging more efficient for pollinators.

Invasive Species
Remove invasive plant species while minimizing soil disturbance
Use Local Genotypes
Use local native plant communities as cues for plant selection then purchase plants that have been grown locally
Reduce The Size of Your Lawn or Create a Pollinator Lawn
Replace a portion of lawn with forage plants or incorporate forage plants in your lawn
Visually Attractive Planting (For Pollinators)
Plant forage plants in masses to create better visual attractants for pollinators

Pesticide Poisoning Prevention

Native plants also attract beneficial insects that prey on 'problem pests'. Both solitary and social wasps visit flowers for nectar and help keep problem pests in check.

Native plants also attract beneficial insects that prey on ‘problem pests’. Both solitary and social wasps visit flowers for nectar and help keep problem pests in check.

Purchase plants from retailers that do not use systemic insecticides including neonicotinoid-based insecticides during nursery production. If systemic insecticides have been used, the plants potentially remain harmful to pollinators for several months to a few years after you plant the plants in your landscape

Determine what the problem is first, learn everything you can about the insect or disease, then make an informed decision of how best to minimize pollinator poisoning.

Use non-chemical methods to control pests whereever possible

Restrict or eliminate pesticide use, especially when forage plants are flowering. Most insecticides, some herbicides and some fungicides are harmful to pollinators.

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Comments

  1. michele says

    Hi, Heather! Extremely interesting & informative article!! I’m trying very hard to include lots of good stuff in my urban garden, including a scrub pile & wild area. I have a couple of questions if you don’t mind!? I had thousands of different insects this summer, from the tiger swallowtails every one got to these little green bees. What are they?? Also, I leave leaf litter & lily stems all winter for nesting, etc. When can I cut down the lily stems in spring safely? I bought an insect book but sometimes it’s difficult to tell from the illustrations what I’m seeing in the garden! Thanks!

    • says

      Hi Michelle,
      Your little green bees could be a number of species including Agapostemon, Augochlora, Augochlorella, Augochloropsis spp. If you took a photo, you can always submit it to BugGuide.net to find out more.

      I wait to cut down stems until my soil temperatures reach 50 F. Many insects will emerge by this point BUT cavity-nesting species will still be in the stems if they found an entry point (hole) the previous summer. If the stems are in tact, then it’s likely there aren’t any cavity-nesters within. Cut in large pieces then place on the ground or bundle a few together and hang facing east for use that season.

      Heather
      Heather Holm recently posted..Book Release: Pollinators of Native Plants

  2. Patti Farris says

    Hi Heather,
    I started a pond a year ago, dug the hole but never got around to putting in the liner, etc. This spring, dozens of bees were nesting in the sides. This went on for the rest of the summer. Is it safe to line the pond now, or would they have overwintered in there? I don’t want to bury them; will I ever be able to fill in this hole or finish this pond without disturbing/destroying bees? Thanks for any insight you have into this dilemma.

    • says

      Hi Patti,
      It sounds as if you saw a lot of activity in the spring – this could be mining bees, Andrena spp. That activity was several female bees provisioning nests and laying eggs (in separate holes). This means that the offspring are likely to emerge around the same time this coming season in late spring. The newly emerging adult bees excavate their way out of the nest, if your liner is covering the side they will probably find their way upwards and emerge.

      The problem is the new generation may want to nest in this ideal site you have created for them and repeat the cycle. It sounds like they selected part of a slope in the pond. Consider creating a similar slope close by facing the same direction as the part used in your pond to provide these bees with an alternative nesting site.

      If it was one hole with many individuals coming in out (lots of activity) throughout the season, then the nest was probably a yellowjacket nest. If that’s the case then all the wasps in the colony died in late fall (except for a mated female – queen) and you could go ahead with the pond liner.

      Heather
      Heather Holm recently posted..Book Release: Pollinators of Native Plants

    • says

      Hi Pam,

      Not that I know of. I would recommend buying from small native plant nurseries where you can ask the staff/grower that question. The most recent studies found neonics in plants sold at “big box” stores that were purchasing the plants from large wholesale growers.

  3. jennie bell says

    Hi –
    I live in an urban area and have worked hard to create a wildlife friendly garden. I have made an effort to include lots of bee and bird friendly plants – and now its come to my attention that some of the plants I’ve been purchasing have been sprayed with some kind of pesticide at the garden center !!! I don’t use that stuff and am worried that the plants may contain harmful chemicals. How can I test my plants to find out if they are OK ?
    Thanks for your help
    Jwnnie

    • says

      Hi Jennie,

      As far as I know, there isn’t an organzation offering testing. If the plants are perennials (not shrubs or trees) and you have had them in your garden for more than a year, the plants are likely okay for pollinators. Shrubs and trees may be harmful for a few years depending on how the chemical was applied (topically or as a soil drench). If you’re really concerned, you can net the shrubs while flowering this year to prevent pollinators from accessing the flowers.

      Heather
      Heather Holm recently posted..Ground-Nesting Bee Profile ~ Unequal Cellophane Bee, Colletes inaequalis

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  1. […] We can all do more (or less) to manage our landscapes for pollinators. Resist the urge to clean up your landscape; instead, leave natural items such as plant stems, logs, dead trees and leaves. Pollinators need undisturbed, pesticide-free, habitat-rich, plant diverse landscapes in order to thrive. Here are some ways we can all improve pollinator habitat in our own yards:  […]

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