Sandy Farber Bandier
advises choosing a mix of plants that bloom at different times of the year for year-round pollinator food sources.
When the University of the District of Columbia
(UDC) received a grant to establish green space on one of its school rooftops, Cooperative Extension Agent/DC Master Gardener Coordinator Sandy Farber Bandier admitted it was the first time she had been asked to develop a garden on top of a building. Regardless of the location, having a plan when you’re starting a garden is a good first step.
The “green roof” garden is thriving in its first year, despite the occasional high altitude-related worrying. “We had a storm recently with 60-mile-per-hour winds,” Sandy said. “I came up here afterward, and everything was fine.”
The 20,000-square-foot rooftop project received funding from Bayer as part of the Feed a Bee initiative
to include pollinator-attractant plants in the garden. Bee hives are in the plans for the rooftop garden in 2016, but no hives were needed for the garden to begin attracting bees. Sandy was surprised with how quickly area bees found their way to the rooftop. In the first month of the project, she saw plenty of bees. By summer 2015, the garden’s sedums were blooming and “covered in bees”.
When putting together a plan for a pollinator garden, Sandy offered some advice that holds true, no matter what the altitude:
- Choose native, pollinator-attractant plants. Pollinator Partnership’s Bee Smart mobile app helps gardeners select the best native plants in their area to attract bees. Seed catalogs offer another way to learn more about pollinator-attractant plants.
- Place plants that need more water closest to the water source. For example, a new variety of lavender, Platinum Blonde, was among the plants Sandy chose for locations furthest from the water source. “Lavenders need to dry out,” she noted.
- Provide fresh, clean water. Bees need a place to get water. Provide a water source for them in your garden and be sure to keep it full and in the same place to they can keep returning for refills.
- Consider flower colors. “We currently have a lot of purple and yellow flowers blooming,” Sandy said. Bees see colors that humans cannot see and are most attracted to flowers that are yellow, blue or purple.
- Extend the season. Choose a mix of plants that bloom at different times of the year for year-round blooms and pollinator food sources. Some of the green roof plantings bloom into the fall, such as Rose Mallow hibiscus and coneflowers.
- Don’t forget about trees. Another way to extend the season for bees is to plant flowering trees. Trees often bloom earlier than other flowers in the spring, providing early sources of pollen for bees. Early sources of pollen for bees include pussy willow, oak, poplar and ash.
- If a plant isn’t doing well, try something different next time. “Once we’ve gone through the first year with our rooftop garden, we’ll have a better idea of what’s working and what we want to plant next year,” Sandy said.
The UDC rooftop garden consists of four raised planting boxes in “T” shapes. The perimeter of the rooftop is lined with 117 (3 ft. x 1 ft. x 18 in. deep) raised planters. There are 146 boxes growing produce, and the garden contains 11 other types of pollinator-attractant plants, including: purple coneflower (Echnacea purpurea), black-eyed Susan (Rudbeckia fulgida ‘Goldsturm’), false indigo (Baptisia), common milkweed (Asclepias), and goldenrod (Solidago ‘Golden Fleece’).