Article and photos by Rob Danforth
Wind, vibration, and a great many different insects act as pollinators, and all are essential to successful gardening! To attract and keep pollinators, imitate nature by promoting biodiversity in vegetables, herbs, flowers, & flowering weeds.
Non-native plant species have a tendency to upset the local ecological balance and that can lead to more bug problems than one needs. A food garden by itself is also an upset to the balance as it is not a “natural” occurrence. To approach a natural balance, we recommend biodiversity and the inclusion of native species in flowers, wild flowers, and flowering weeds where possible. If necessary, pot them to contain them, and place them strategically.
Pollination: pollen (generally a sticky powder) is transferred from the anthers (male part) of a flower to the pistil (female part) of the same flower or that of a neighbouring flower. The flower is now ready to produce seeds (e.g. calendula) or fruit containing seeds (e.g. squash).
Cross-pollination – one plant pollinates another (e.g. green zucchini plant pollinates another green zucchini plant to beget green zucchini) but also different varieties of a plant can pollinate each other (e.g. green zucchini + yellow zucchini begets bi-colour zucchini). Many plants can be cross-pollinated: squashes, cucumbers, melons, parsley, cabbages, chard, broccoli, mustard greens, celery, spinach, cauliflower, kale, radish, beets, onion, and basil. Caution: weed relatives can also cross-pollinate with food garden plants (e.g. Queen Anne’s Lace with carrots, wild parsnip with garden parsnip). Oranges, lemons, & limes are the results of cross-pollination.
Self-pollination occurs within one flower or between flowers of the same plant: broccoli, cantaloupe, cauliflower, cucumber, beans, lettuces, okra, snap peas, squashes, tomatoes, watermelon. Some plants like squashes and cucumbers have separate male and female flowers on the same plant. Naturally, only the female flowers (see swelling at the base) produce fruit.
Special Note: GMO versus GEO – unfortunately today, GMO (Genetically Modified Organisms) is commonly used to mean GEO (Genetically Engineered Organisms) . GMO is natural but GEO is unnatural. If the male comes from one gene pool and female comes from a different gene pool then the offspring are the genetic modifications of those two combined gene pools which determine particular body features such as those of a mule (horse + donkey), coywolf (coyote + wolf), and beefalo (bison + domestic cow). Different gene pools can strengthen generations of an organism, and avoid the potential problems of inbreeding. Charles Darwin studied natural changes in genetic traits in the 1800’s!
GEO’s are designer plants constructed in a science lab; they do not occur naturally. Very specific genes are taken from one species and inserted into the gene strands of a different species. Some plants are engineered to change their composition or features, to fight pests, or to tolerate herbicides so that acres of a crop can be weed free (e.g. canola). The unknown long term effects of GEO plants on nature’s biodiversity and on people are topics of much concern.
- Insects feed on the pollen, but some sticks to their bodies and rubs off on the pistil of the next flower they visit. Bees, moths, beetles, butterflies, mosquitoes, …. and at times, even some birds (e.g. hummingbirds) all assist in pollination.
- Vibration, known as “buzz pollination,” shakes pollen loose within the same flower in eggplant, peppers, and tomatoes.
- Wind blows pollen from plant to plant in beets, grains, rice, swiss chard, and corn (the TV-like antenna above a corn plant is male and the corn silk is female).
- Home Gardeners use a paint brush or Q-tip to pollinate indoor fruiting plants (I used a paint brush for indoor tomatoes). If you try outdoor hybrids (i.e. gardener controlled pollination), cover plants with a bag or bug net to isolate them from additional pollination. Hybridization is a natural pollination, just gardener guided.
- Various laboratory techniques are used for GEO plants and their pollen for cotton, corn, soybean, papaya, rice, …. GEO plants may be copyright protected.
- Avoid all use of chemicals: pesticides, herbicides, fungicides, and chemical fertilizers.
- Fertilize with organic compost, or composted manure.
- Add bug restaurants, bug hotels (see article in “seasonal resources” on Bug Hotels and Restaurants) and a water feature – yes, insects get thirsty.
- Add some Dutch White Clover to lawns or make permanent garden paths of Dutch White Clover – the clover flowers often and is attractive to pollinators (and rabbits).
It is important to attract and keep pollinators with biodiversity because vegetable plants alone flower less often – pollinators need more consistent, long term food sources.
- Bug restaurants such as flowers, local weeds (e.g. goldenrod), and wildflowers (e.g. trilliums), should be open 24/7 spring through fall and offer a variety in bloom times, sizes, shapes, colours, and fragrances. If you are just starting biodiversity, choose yellow flowers or flowers with yellow in their throats for daytime pollinators and white flowers for day and nighttime pollinators (white flowers show up in the dark and often have stronger fragrances – e.g. cimicifuga). These two colours are very popular with pollinators as is the colour red for hummingbirds.
- Bug hotels are low to the ground, year round, all weather facilities that benefit from protection from critters that eat bugs, such as birds, rodents, toads, skunks, and raccoons.
- Water features such as a bowl of water, bird bath, fountain, or pool, should have a few rocks or low brims to offer shallow areas so bugs do not have to swim to get a drink.
- Interplant vegetables and herbs among flowers or flowers among the veg and herbs; insert pots of flowers/flowering weeds in strategic locations; and allow some weeds to flower. Caution: on flower gardens that also contain food plants, avoid chemicals and use organic fertilizers. Do-it-yourself compost is highly recommended for all gardens.
Note: the fragrances of vegetables, herbs, flowers, and weeds float on the breezes; the bugs will come: the good, the bad, & the beautiful!
Here is a list of flowering plants that we have used at various times – some, every year – to provide plentiful and diverse food sources in our backyard and community gardens:
Asian Lilies (beetle resistant variety), Aster family, Begonias, Bergamot (“Bee Balm”), Borage, Calendula (“Pot Marigold”), Clematis, Cleome, Columbine, Comfrey, Cosmos, Crocus, Daffodils, Dahlias, Day Lilies, Dutch white clover, Echinacea (“Coneflower”), Feverfew, Garlic chives, Hyacinth, Hyssop, Iris, Lavender (“English”), Lantana, Lily of the Valley, Marjoram, Muscari (“grape hyacinth”), Nasturtiums, New Guinea Impatiens, Oregano, Portulaca, Rudbeckia (“black eyed susan”), Scaevola, Sedum, Snapdragons, Sunflower, Tansy, Thyme (creeping variety), Tulips, Verbena, Yarrow, and Zinnias.
Note: let herbs flower if you wish to collect seeds; however, removing the flower heads helps concentrate the flavorful oils in the leaves. Chives (purple flower), garlic chives (white), and dill (yellow), are exceptions – we let them flower.
Bee Notes – There are hundreds of kinds of bees worldwide. I have identified 5 different kinds in my Ottawa backyard. They sleep in until the warmth of the sun helps get them up, and on early summer mornings, you may find them dozing on flowers just before the sun finds them.
Many bees are solitary and stinger-less or non-aggressive and thrive on variety in diet rather than a monoculture of one kind of plant. Some bumble bees, purchased for greenhouse bee boxes, leave the buildings for a change in diet – some do not return.
A great many bees are ground dwellers; I was stung by ground dwelling bees, and I witnessed 3 serious attacks on gardeners and grass cutters. If you are allergic to bee venom, mulch will discourage ground nesting bees, and gardening in the morning & evening, before and after bees are active, will significantly reduce the chances of contact. If need be, smoke in the hive/hole stupefies – makes bees docile so you can manage them. Full body cover is recommended!
Some bees overwinter in berry canes, bamboo, and garden detritus. Consider cutting & dropping the soft parts of finished plants as mulch on the surface of plots and large containers, and leave stubble in-soil until spring as bee habitat.
As a high school student in northern France (1963), I set up and maintained a honey bee hive for instructional purposes. Although a few community gardens have hives, they are not essential for urban gardens, as nature will provide ample pollinators. However, anything you can do to encourage pollinators of all kinds to come and stay will benefit your food and flower gardens. Offer the pollinators long term food and shelter and they will not only come, they will move in! Happy Gardening!