The presence of pollinators on flowers depends on many factors, so it is hard to know exactly why they are not visiting your flowers as much as you would expect. Plus, sometimes these factors happen simultaneously, so it may be that it is not one but the combination of factors that leads to the lower floral visits one sees. In today’s post I would like to touch on some potential reasons of why flowers may not be visited, and what we all can do to change it!
Are there really no pollinators?
We tend to think of pollinators as honeybees, and if we don’t see them we think that there are no pollinators. Pollinators come in a huge variety of types (see here to learn more!), and although you may not be attracting a lot of honeybees, you may be doing great at sustaining other pollinators!
To test if this is what is happening in your flower patch, observe carefully the flowers to see if there are other insects visiting them. Those may be pollinators too! Indeed, small wild bees, syrphids, and small beetles visit flowers often, but are usually inconspicuous. Also, make sure that you are observing your flowers when pollinators are most active, which tends to be under sunny and warm weather conditions.
Pollinators have not yet had time to find your flowers
Especially if your flower patch is in an area or neighborhood where there aren’t many flowers, the pollinators in your area will need a bit of time to know that the flowers are there! It’s like when a new shop opens and it takes a while for people to know it exists. If you continue to have flowers there over the season and years, pollinators are going to start coming more regularly and you should see an increase over time.
Not sufficient(ly diverse) flowers
If you indeed live in a region where there are not many floral resources available for pollinators, you can plant more (diverse) flowers next year and/or talk to your neighbors and have them plant flowers too! The more flowers in a region/neighborhood, the more pollinators you may end up attracting overall! On this, consider talking to your City leadership and inquire on whether they would be interested in supporting pollinators by becoming a certified Bee City USA city.
Lots of flowers but not many places to nest
Even though most pollinators can fly to get to floral resources, their flight ability depends on the species. Some species can fly some miles, while others forage just close to their nests. To make sure that there is a lot of pollinator diversity in your flower patch, you can create conditions that favor the nesting of those species that can’t travel far. For this, a great thing to do is create nest-friendly spaces on your property. One can also establish practices that ensure that critical pollinator developmental stages (e.g., overwintering stages, larval development) also have sufficient resources. This can be done, for instance, by leaving leaf litter on the ground over winter and protecting overwintering spaces (check this other post to learn more).
Some pollinators are territorial
Some pollinators (e.g., some bumblebees, honeybees, large carpenter bees, wool carder bees) can “push out” other smaller pollinators, especially while the males are looking for a mate. If the large ones are very abundant, it could be possible that they are chasing away the small ones. This would not explain an absolute lack of pollinators, but would be able to explain certain drops in abundances at certain times of the year.
Pesticide drift
Pesticide drift is a big problem for the protection of beneficial arthropods, and can lead to pollinator (and other beneficial insects) death. Drift happens when a region in the vicinity of your property is treated with pesticides, and the products drift into your property. This is really problematic when the applications are done at the wrong times, with the wrong concentrations, or using the wrong means. In particular, this can be a problem when homeowners decide to perform whole-yard spraying to control mosquitoes, which is not recommended (an exception to this are controlled community-wide sprays occasionally done by the State Department of Agriculture if disease spread –e.g., West Nile Virus — is a concern).
Unless there are strong reasons for pesticides to be continuously applied in the vicinity of your property (e.g., major and sustained outbreak of mosquito populations), this is normally restrained in time. If there has been drift, you would be seeing a drop in pollinators compared to a previous time in the year (say, the week prior to the potential drift event). If drift has actually happened, but is not happening anymore, one would expect to see the populations of your pollinators increase with time, since new pollinators could be attracted from other surrounding areas. If you suspect that drift is an issue, you can discuss with your neighbors and see if the applications are really necessary, if they are done at the proper times (ideally in the night or when beneficial insects are not active) and/or get them in touch with your UMD Extension officers, who can recommend whether treatment is even needed, and if so, how to do it. You can send your question online to Ask Extension.
Just a less-active year
If you have been successful in the past, it could just be that this year there is just a smaller population of pollinators in the area when your flowers are growing. For example, maybe the warm winter did not help some pollinators properly overwinter, or some disease outbreak locally affected pollinators in your area. If next year you realize that this was indeed a one-year thing, this will then be easily explained by natural fluctuations in pollinator populations.
Think broadly and don’t give up!
Remember that sometimes it is not one but the combined effect of these factors that makes that pollinator abundances drop in our gardens. If you’re not sure what the actual reason may be, your best call is trying to implement as many of the actions as you can, so at least you can exclude some variables. Either way, remember that your actions are likely not going to bring results from one day to the next, but rather from one season to the next! For example, many pollinators reproduce only once per year, so you may have to wait until the next generation (the following year) to see a difference. So, don’t give up if you don’t see an effect right away! You’re likely doing the right thing; you just need to wait a bit longer to see the result!
By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.
Anahí also writes an Extension Blog in Spanish! Check it out here, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!
Another possible cause is planting a cultivar of a good bee plant. When plants are bred for their color or height, inadvertently the quality of their pollen or nectar may be degraded. For instance, Autumn Joy is touted as a bee plant, but if you visit a nursery with a good selection of sedums in bloom, Autumn Joy isn’t a favorite with the bees. The straight species are likely to be good, but cultivars can be hit or miss.