David Smitley, Michigan State University Extension, Department of Entomology, has produced a new 2019 update now available for the most complete guide to protecting pollinators while gardening, growing flowers or managing trees, shrubs or turfgrass in urban areas.
Many people are concerned about declines in the number of bees and butterflies, especially honey bees and monarchs. To help gardeners and others in urban settings identify how they can protect and increase populations of pollinators, I worked with a team of ornamental horticulture experts, plant pathologists and entomologists to update a guide full of resources and recommendations. An updated version of “Protecting and enhancing pollinators in urban landscapes for the US North Central Region” is available online for viewing and in PDF format for free downloading.
This online publication includes:
Factors that threaten pollinator health.
Detailed recommendations for selecting annuals, perennials, shrubs and trees that support pollinators including butterflies.
Unique to this publication, best management practices for managing devastating exotic pests, or troublesome outbreaks of native pests, while minimizing impacts on pollinators. These practices include trunk injections and the use of low-impact pesticides.
A detailed phenological table that tells when the most common trees and shrubs bloom so that sprays can be avoided until they are done blooming.
A list of 89 references for those that would like to read more on this subject.
See it all here