In order to call your garden home, pollinators need food, nest sites, and a safe place to live. For food, bees gather nectar and pollen from flowers.
Provide flowers from April to October so bees have a constant supply of food. Ideally, start with 3 kinds of flowers for each season. Add annuals to fill in gaps in bloom times, especially while your other plants are getting established and aren’t mature enough to bloom yet. A garden in sun or part-sun is best.
When I started my garden, I wasn’t very familiar with native plants. I didn’t know when they bloomed or in what order they typically bloom. I still feel that I don’t have enough, or early enough, flowers for spring. I found the Minnesota Wildflowers What’s in Bloom? pages useful for trying to find flowers that would bloom one after the other with some overlap. Obviously there will be differences here in Ottawa, and the bloom times are shifted later. I could see that bloodroot and Hepatica are among the earliest blooming plants, and that wild strawberry and violets should bloom after.
Unfortunately, with climate change, bloom times have gone a haywire, and may no longer coincide with the pollinators that depend on them. These case studies, Bees and Flowers Out of Sync, Climate Change Blamed and Unusually Hot Spring Threw Plants, Pollinators Out of Sync in Europe, show that flower and bee times is becoming mismatched.
Plant in patches
Group together 3 or more of each type of plant. Bees and butterflies will be able to see these drifts of flowers from a distance, and the patches of flowers will provide lots of food in one spot. The City of Guelph has created helpful pollinator garden plans for different conditions. You can see groups of each type of plant on their diagrams represented by similar symbols in the same colour.
Nectar and pollen
Plants must provide both nectar and pollen. Nectar provides energy. Pollen provides protein for growth — for egg development in female bees, and for provisioning nests to feed larvae after they hatch. Some flowers provide only pollen, and others provide both pollen and nectar.
To find out which resources a native plant provides to bees, and other wildlife, I like to check the Illinois Wildflowers web site. Each plant page includes a description of its “Faunal Associations”. For example, on the page for bloodroot, I learned that these flowers only offer pollen to early bees. It can get complicated to keep track of which flowers provide which resources, so I simply aim for variety and hope that all the bees’ needs are covered.
Different flower shapes and sizes
Different kinds of pollinators need different flowers, which is often dictated by bee tongue length and how far they can reach into flowers. Include a variety of shapes and sizes, so there’s food for all your insect visitors. Bees favour white, blue-purple, and yellow flowers. Bees see ultraviolet light, so flowers look different to them than they do to us, so perhaps flower colour isn’t really that important. For information about bee vision and how they see flowers, visit the How Plants Work article “Flowers: What You See Versus What The Bees See”.
Avoid plants with double flowers because pollinators cannot access the nectar and pollen through the densely packed petals, if these heavily hybridized flowers even still offer nectar and pollen. Generally, be wary of cultivars of native plants, that have been bred or selected for particular aesthetic characteristics, because they may no longer be beneficial to pollinators. Researchers are currently studying native plant cultivars. Learn more about Annie White’s ongoing research in an EcoBeneficial interview. Listen to Margaret Roach’s interview with George Coombs about Mt. Cuba Center’s native plant cultivar test trials. Unless you are choosing plant cultivars based on these research results, it’s best to stick with seed-grown, natural versions of native plants.
Don’t use pesticides in your pollinator garden. Also avoid buying plants from stores or nurseries that use them. The chemicals remain in leaves, nectar and pollen, and will poison the bees and butterflies you are trying to help. For more information, see my page on avoiding pesticides.