We have temporarily closed all Denver Botanic Gardens locations. Denver Botanic Gardens’ response to COVID-19
While things are mostly quiet in the Gardens this time of year, there’s plenty of work going on backstage in the greenhouses. Down at Chatfield Farms we have two large production greenhouses where we also store tender plants over the winter. Many of the large containers of tropical or other non-hardy container plants that you see in the York Street Gardens during the summer spend their winter vacation resting at the greenhouses at Chatfield Farms. Since these greenhouses are not open to the public, I thought I would share the wintertime lives of these tropical plants.
We keep the greenhouses cool to reduce the pest and disease pressure, and to keep the plants growing slowly. At night the greenhouses can get as cool as 45 degrees F. Their watering is also reduced to keep them dormant, and many of them are cut back to conserve space. While the relatively cold temperatures and hard cutbacks might seem harsh, it is important in order to keep these plants healthy and looking good during the summer.
Even though tropical plants aren’t adapted to winter-summer seasonality, they still experience seasons in their native habitats with wet-dry seasons. The plants from these climates go through a reduced growth dormancy during the dry season much like temperate perennials. If we kept these plants growing through the winter when light levels are low we would end up with flimsy, leggy plants come spring.
Large bananas (Ensete ventricosum ‘Maurelii’) from the Victorian Secret Garden at York Street are cut back and stacked to conserve space. They are kept dry to keep the plants dormant. The plants are placed on plastic grates to keep them from rooting into the gravel.
The beautiful succulent tray (Echeveria setosa) that was on display in the Sensory Garden at York Street under a kaleidoscope has had most of its rosettes removed, so the only growth is tiny buds on bare stems. By spring this basket will have flushed with growth, and will be healthier than if we had left it alone. We potted up the removed rosettes to bring to the Grown at the Gardens division of Spring Plant Sale.
While not tropical, the large Agave americana are not quite hardy. The plants are huge, nearly six feet across, and have hooks all along their leaf margins. Moving them and watering around them can be an adventure. They can be seen on display outside the Chatfield Farms Earl J. Sinnamon Visitor Center during the summer. The several different cycads (Encephalartos spp.) are displayed in the South African Plaza and Steppe Garden at York Street during the summer.