Guidlines for choosing plant species

When it comes to building a pollinator garden . . . . Go native, Be diverse and Be informed!

There are many things to decide upon when designing and building a pollinator garden, but none so important than the species you will plant. Your choice of plant species will ultimately dictate the type, frequency, and diversity of pollinators that will visit your garden.

We have listed a few key concepts here to remember when choosing species for your pollinator garden. Remember the pollinators are counting on you!

1.  Go Native!  Encouraging native plant species

Native plants are those that are naturally occurring in a specific geographical location and are often adapted to the soil and climate of the area. Choosing to include native species in urban green-space environments is considered a best practice by most conservation- based gardeners. This is because in general, these species are more robust, require less water, and are less prone to disease or pests.

Their inclusion in pollinator gardens is crucial not only because of the climate suitability reasons listed above, but because native plants and native pollinators have become mutually adapted through millions of years of partnership.

Photo credit: wiki commons, user: Moxfyre

Photo credit: wiki commons, user: Moxfyre

2. Be Diverse! Encouraging plant species diversity

Providing a variety of native flowering trees and shrubs and wildflowers that bloom successfully throughout the year will increase the diversity of pollinators utilizing your garden and promote continual visits throughout the seasons. Providing blooms from early spring through late fall will help provide food and habitat needs for pollinators to survive through the changing seasons.

Photo credit: ABG archives

Plant diversity significantly affects bee diversity. Studies have shown that in urban environments bee abundance and bee diversity within a garden increases with plant biodiversity and floral abundance (Hennig and Ghazoul, 2012. Pollinating animals in the urban environment. Urban Ecosystems, 15, 149-166.)

larva_dw_pic10806_lg forest service polli o the month

photo credit: US Forestry website, Pollinator of the month. Photo by Dick Walton, Monarch monitoring project

Diversification in plant species is also very important for attracting butterflies. Different species  have distinct color preferences, feeding behaviors, and proboscis lengths which determine which species they will visit. Click here to learn about butterflies and their pollination syndromes.  You should also consider including plant species that support both the adult and larval stages of the butterfly’s life cycle. This would mean including nectar source plants for the adults and food plants that act as hosts for the larvae.

Plant diversification should also incorporate differing habits to encourage both ground feeding pollinators and those that forage or dwell in trees and high shrubs. Not to mention, differing levels of height in a garden also is aesthetically pleasing!

Remember the more diverse your garden is the more diverse your pollinators are.

Don’t forget to include night or dusk opening flowers to attract night pollinators: moths and bats!

3. Be informed!  Keeping pesticides out of your plants, garden, and pollinators

A study undertaken in 2010 across apiaries in North American orchards recovered over 120 agrochemicals in honeybees pollen and wax. (Mullin, et al 2010) While it is understood that most urban pollinator gardens will not be applying large amounts of chemicals in concentrations similar to a commercial orchard, the point remains that the chemicals in pesticides are transferable to our pollinators.

Foraging bees can intake pesticide through direct contact on their integument, by drinking toxin-tainted nectar and by consuming insecticide-covered pollen.  More often than not exposure such as this will result in death.

Even less-than-lethal doses can be catastrophic to native bees, causing problems such as navigation trouble after foraging, loss of ability to fly, jerky or wobbly movements, and even paralysis. Secondary effects on developing larvae can also occur when toxins are brought into the nest from tainted pollen and nectar. Infected bees may also have problems building nests and laying eggs, which compounds issues of bee decline by directly affecting the next generation of pollinators.

Click here to learn more about how pesticide use is causing a decline in our native pollinator numbers.

Herbicide and pesticide usage in your pollinator garden
The best practice for small to medium home, school, or local pollinator gardens is to avoid using pesticides completely.

Here are some alternative measures that can be taken to managing pests:

1. Beneficial insects.  Encourage native predators of your pests through a diverse garden habitat that includes plant species favorable to the predator.  Some species are also available commercially online as live specimens or eggs.

One example is the green lacewing whose larvae can consume 200 or more insects or insect eggs a week during their three week developmental period.  See this website here for an example of a purveyor of beneficial insects.

2. Expect and accept a small amount of pest activity. Small populations of pests in your pollinator garden can be ignored, and may be a great indication that you’re doing a good job. As long as the populations are not huge in numbers or becoming a detriment to visiting pollinators, it’s okay to leave them be. After all, pollinator gardens are planted for a purpose: they are useful and efficient; they are not meant to be structured, ordered, or perfect.

(Photo credit: Wiki commons, Author: Hyena)

3. Try removing pests by spraying them with water, or use gloves to remove by hand if the pests are few. Aphids and other small pests can often be removed with a strong spray of water from a garden hose

4.  For mosquito control, remove large areas of English ivy and any areas of standing water. Both promote damp and wet areas that  create a perfect breeding environment. Think about upturning wheel barrows and large unused pots, covering empty plastic kiddie pools, and checking woodpile tarps for water collection.  You can also use cedar oil or citronella oil in outdoor furnished areas to discourage mosquitoes.

(Photo credit: Flickr, Author: Sara Stasi)

5. Try some friendlier chemical alternatives such as neem oil or insecticidal soaps.

Systemic insecticides, the unknown pesticide threat!

A new threat has developed with the introduction of a new insecticide. It was designed to mimic toxins found in nicotine.  As a systemic pesticide, uptake occurs through the plants vascular system. It is applied as a seed treatment, foliar spray, or root treatment.

Some research has suggested that these chemicals are then sequestered in the flower and pollen of the treated plants, and therefore pose a threat to pollinators. Unfortunately, unless commercial nurseries are advertising their pesticide use in phases of a plant’s life, from germination through sale, it is hard for consumers to be informed and wise when purchasing plants.

Systemic pesticides are also very harmful to those pollinators who either eat or use the leaf portion of the plant. This would include butterfly caterpillars who use host plants for food and leaf cutter bees who use leaf portions to line larval nests.

Click here for more information on nicotine based systemic based pesticides.