Last weekend I was researching green roofs in New York City and finally got the chance to go see the new visitor center at Queens Botanical Garden in Flushing, Queens. It was raining that day so I could really see how their rain water harvesting system works. The shelter over the visitor center entrance is essentially a massive gutter to catch rain. The harvested water drips over the lowest corner and into a bed of river stones which feeds into the biotope. The biotope is a system for cleansing fallen water and using it for both watering plants and water features around the garden so that QBG can rely less on the city's water supply. (Refer to QBG signage below for more detail). Rain water harvesting systems are easy to incorporate into most gardens, and on a large scale they are a great aid to the ever-present storm water management issues we face in New York City.
On the other side of the new buildings at QBG is a new auditorium, fully equipped with this impressive intensive green roof system on top of it. As you walk up the path you are walking onto the roof itself.
Being an intensive green roof system, which is typically 6" or more of growing medium, they are able to grow a wide array of grasses, native perennials, meadow plants, and many different low-growing succulents. Even in winter all the colors and textures in the garden made it so rich and beautiful looking, I can not wait to see it again in summer.
A well constructed green roof can be more costly and involved to install, but the long-term benefits to the individual and the city are invaluable, and definitely a direction we need to go in as a society. A typical roof eventually breaks down after 15-20 years due to exposure to the elements, sun moistly, then rain and precipitation, and wind. By creating an effective waterproof buffer of plants and growing medium the impact of the elements is greatly lessened because the plants are using those same elements to their benefit to grow and spread. A mature green roof regulates the surface temperature of the roof, thus diminishing energy costs, lowering your bills, and allowing you to rely less on the city's energy supply. The plants will require supplemental irrigation to get established but they are drought tolerant species so eventually the rain will provide enough natural irrigation to keep them going. By using the rain water the amount of runoff is greatly reduced, another aid to storm water management here in New York City. The realities of a green roof are that they do require some ongoing maintenance and initially you will have to consult with at least an engineer, architect, and landscaping contractor.
But the results are that you get to look at amazing plants instead of plain gray rooftop that isn't helping anything. Above is a kind of
Sedum.
Sedum are probably the most utilized genus of succulent plants used in green roof technology in the northeastern U.S. They come in a number of colors, shapes, and sizes, and the bulk of them are excellent drought tolerant species that spread well and are easy to maintain.
Many people know the upright Sedum 'Autumn Joy' and similar cultivars and in an intensive green roof system they are perfectly viable plants. Here you can see last years growth which was left on for its fall and winter interest as well as the new flush of growth for this spring.
After marveling at the green roof for a while I decided to see what else was in bloom around Queens Botanical Garden.
If you have taken a walk through a large park or garden recently you have probably spotted the Galanthus in bloom, commonly called snowdrops. These spring bulbs grow in tight clusters and put out these unique and ornamental nodding white flowers just before the daffodils and tulips begin to burst. The two species I learned in horticulture school were
Galanthus nivalis and
Galanthus elwesii, the major difference being that
G. elwesii has two green spots on their flowers while
G. nivalis only has one. I would guess these to be
Galanthus nivalis. Native to Eurasia,
Galanthus do well in USDA Hardiness Zones 6-9 in a compost rich soil with good drainage.
Also in the Woodland Garden at QBG were some
Helleborus still holding on to their flowers. Commonly called winter rose, these low perennials are native to Europe and Asia and provide spectacular flowers in a woodland garden through the dead of winter. With so many species and cultivars in the trade now you can find them in a wide range of green, white, pink, red, maroon, and purple.
And finally, not quite in bloom, but the selection of flowering cherry trees were budding up well and showing their potential for a few weeks from now. This is a
Prunus 'Okame' which you can tell will have some beautiful pink flowers in nice dense clusters. Looking closely at all of the different
Prunus species on display it seemed apparent that 'Okame' is one of the first species to bloom for us here in the city. This particular specimen was only about 12 feet tall but I have seen them as large as 20-25 feet.
On the other side of the new buildings at QBG is a new auditorium, fully equipped with this impressive intensive green roof system on top of it. As you walk up the path you are walking onto the roof itself.
Being an intensive green roof system, which is typically 6" or more of growing medium, they are able to grow a wide array of grasses, native perennials, meadow plants, and many different low-growing succulents. Even in winter all the colors and textures in the garden made it so rich and beautiful looking, I can not wait to see it again in summer.
A well constructed green roof can be more costly and involved to install, but the long-term benefits to the individual and the city are invaluable, and definitely a direction we need to go in as a society. A typical roof eventually breaks down after 15-20 years due to exposure to the elements, sun moistly, then rain and precipitation, and wind. By creating an effective waterproof buffer of plants and growing medium the impact of the elements is greatly lessened because the plants are using those same elements to their benefit to grow and spread. A mature green roof regulates the surface temperature of the roof, thus diminishing energy costs, lowering your bills, and allowing you to rely less on the city's energy supply. The plants will require supplemental irrigation to get established but they are drought tolerant species so eventually the rain will provide enough natural irrigation to keep them going. By using the rain water the amount of runoff is greatly reduced, another aid to storm water management here in New York City. The realities of a green roof are that they do require some ongoing maintenance and initially you will have to consult with at least an engineer, architect, and landscaping contractor.
But the results are that you get to look at amazing plants instead of plain gray rooftop that isn't helping anything. Above is a kind of Sedum. Sedum are probably the most utilized genus of succulent plants used in green roof technology in the northeastern U.S. They come in a number of colors, shapes, and sizes, and the bulk of them are excellent drought tolerant species that spread well and are easy to maintain.
Many people know the upright Sedum 'Autumn Joy' and similar cultivars and in an intensive green roof system they are perfectly viable plants. Here you can see last years growth which was left on for its fall and winter interest as well as the new flush of growth for this spring.
After marveling at the green roof for a while I decided to see what else was in bloom around Queens Botanical Garden.
If you have taken a walk through a large park or garden recently you have probably spotted the Galanthus in bloom, commonly called snowdrops. These spring bulbs grow in tight clusters and put out these unique and ornamental nodding white flowers just before the daffodils and tulips begin to burst. The two species I learned in horticulture school were Galanthus nivalis and Galanthus elwesii, the major difference being that G. elwesii has two green spots on their flowers while G. nivalis only has one. I would guess these to be Galanthus nivalis. Native to Eurasia, Galanthus do well in USDA Hardiness Zones 6-9 in a compost rich soil with good drainage.
Also in the Woodland Garden at QBG were some Helleborus still holding on to their flowers. Commonly called winter rose, these low perennials are native to Europe and Asia and provide spectacular flowers in a woodland garden through the dead of winter. With so many species and cultivars in the trade now you can find them in a wide range of green, white, pink, red, maroon, and purple.
And finally, not quite in bloom, but the selection of flowering cherry trees were budding up well and showing their potential for a few weeks from now. This is a Prunus 'Okame' which you can tell will have some beautiful pink flowers in nice dense clusters. Looking closely at all of the different Prunus species on display it seemed apparent that 'Okame' is one of the first species to bloom for us here in the city. This particular specimen was only about 12 feet tall but I have seen them as large as 20-25 feet.
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