It was the summer of bats here at Tudor Place! We just completed three successful public programs dedicated to bat-friendly landscapes and advocating for their habitats here in the District. The story begins last fall when I began my role here in the gardens. 2018 saw an excess of two things: rain (it was one of the wettest years on records) and with that mosquito populations. I recalling not being able to wait until the first frost of the year to curtail the mosquito invasions. Even with bug spray, i couldn’t be outside for more than a few minutes before being swarmed. Around that same time was also butterfly migrations in the garden. Sometimes dozens at a time floating in the same area. Monarchs, black swallowtails and many others. After getting a sense of the plant material in the grounds, I also noticed that we lacked host plants for some of these beauties. Tudor Place has a great collection of old fashioned plant material, but the under story lacks many of the area natives required to fully support resident fauna.
That fall i declared to myself and to my garden advisory committee that I’d like to do more to increase biodiversity in the gardens. I would achieve this by introducing more native plants as well as increasing or creating habitat for native animals that support a healthy landscape. That November, a large white oak tree toppled over and its removal revealed a new large sunny area perfect for the use as a new pollinator garden. My “increasing biodiversity” initiative was underway!
The next step was trying to remedy ongoing issues through the biodiversity campaign. I decided to tackle the mosquito population issue first. I was interested in growing plants and attracting animals that would help control this nuisance. After reading that bats can consume thousands of mosquitoes each night i contacted bat experts in the area and invited them to Tudor Place to explore potential habitats on site.
We first welcomed Deborah Hammer, a local bat expert and educator. She helped us identify the types of species that would be attracted to the area and agreed to do two talks plus bat walks to identify them in real time. Deborah has a cool echo-location meter device that connects to her smartphone and has the ability to identify bats in real time as they fly overhead. During the bat walks we identified 5 different species!
Next we were visited by Lindsay Rohrbaugh, a Fish and Wildlife Biologist with the Department of Energy & Environment. She was encouraged by the potential habitat spaces and offered us a bat house to install on property. Later in the year, in August, she presented a talk on bats on the grounds followed by a bat walk and netting of bats. It was very educational! The bat house design is very unique. It is one of about 20 houses that were made by boy scouts in Michigan using recycled Chevy Volt electric battery covers.
For each of these public programming events, I also took the opportunity to speak about mosquito control and the measures that Tudor Place is taking to reduce populations. Talking points included the following:
- DC’s most common mosquito is Culex pipiens and lays its eggs in clumps on water surfaces. These mosquito eggs are most likely to be laid in our fountains or anything holding standing water.
- DC’s second and third most common mosquitoes Aedes albopictus and Aedes aegypti will lay single eggs in damp areas that are subject to flooding.
- Mosquito eggs typically hatch within 48 hours and become larvae where they will live underwater for 7-14 days. After this stage they become pupae and live on the water surface for 1-4 days. After adults emerge from the pupa they rest on the water surface for a bit and start to feed and mate after a few days.
- No unnecessary standing water; Improve drainage on the property. Make sure nothing on the grounds is holding water
- BTI pond dunks kill mosquito larvae within a few days of ingesting it. Lasts for 30 days in the water and one tablet treats 100 sq. ft. of surface
- Pond gardens will attract beneficial insects such a dragonflies to the area. Dragonfly eggs are laid in pond plants and the larvae feed heavily on mosquito larvae.
- Alternatively, Mosquito fish (Gambusia affinis) can be used to feed on mosquito larvae and pupae.
- Tudor Place uses garlic spray in certain areas to repel mosquito with good efficacy. Garlic brews are homemade and spraying occur weekly or after rains.
- English Ivy reduction. Mosquitoes thrive in the moist shady environment that english ivy can provide. Some leaves may hold water long enough for mosquitoes to reach adult stage.
- Mosquito repelling incense. Tudor Place is experimenting with plants such as Lemon scented-gum and lemon basil to repel mosquitoes when the leaves are burned.