February Walking Tour - Greenhouses and the Orangery
By Nick Snakenberg, Curator Orchids/Greenhouse
The Gardens' Orchid Showcase runs through February 23 and is a great time to enjoy the display of orchid flowers throughout Marnie's Pavilion and the Orangery. It's also a good opportunity to look a bit deeper into the greenhouses behind the displays and see what other treasures are in the collections of Denver Botanic Gardens.
As you leave Marnie's Pavilion and enter the Orangery, the first greenhouse you can look into contains plants from our tropical collections that prefer warm and humid conditions. Of special interest are the many species of Nepenthes, or tropical pitcher plants that can be seen growing in hanging baskets. Some people confuse the ornate pitchers as flowers, but if you look closely, you will see that the pitchers are all produced at the tips of the leaves. The pitchers are actually modified leaves - not flowers. The pitchers contain fluid produced by the plant and when insects enter the pitchers, they drown in the fluid and are slowly digested by the plant. Some species produce pitchers large enough to trap rats and other rodents.
Another showy plant in this first greenhouse is Anthurium scherzerianum (looking into the greenhouse, it is just left of center). There are hundreds of species of Anthuriums throughout the tropics but only a few produce colorful flowers. Anthurium scherzerianum is native to Costa Rica and is sometimes called the pig-tailed anthurium. It's easy to see how it got its common name.
The second greenhouse you can look into from the orangery contains orchids that prefer very warm temperatures. Blooming orchids are rotated into the window for viewing year round but there is currently a stunning display of one species in particular - Laelia anceps. There are many color forms of this Mexican species and they are all in glorious bloom for the next several weeks.
As you continue westward through the Orangery, the next greenhouse contains tropical plants that prefer high light and slightly drier conditions than most of our other tropical plants. Don't miss the oddly shaped Dioscorea elephantipes or elephant's foot yam. Dioscorea elephantipes is a deciduous climber (look directly above you and you'll notice how it has climbed the greenhouse glass and crept through into the Orangery). The tuberous stem can grow to six or more feet across and contains saponins - chemical compounds from which steroidal drugs can be developed. The tubers are edible but require processing to remove toxins.
Also in this greenhouse is a specimen of Wollemia nobilis or Wollemi pine. Long thought extinct, this living fossil was only discovered about 20 years ago in remote mountain valleys west of Sydney, Australia. There are only about 100 specimens known in the wild and their location is a closely kept secret. As part of the conservation efforts, thousands of plants have been commercially propagated to help remove the temptation for collectors to search for the wild population and collect specimens illegally.
Continuing to the west, the next greenhouse contains more orchids. This greenhouse is kept at slightly lower temperatures than the other orchid greenhouse. Again, plants are continuously rotated to the windows for display. Of particular interest at this time of year are the many color forms of Dendrobium nobile from Southern China.
The last two greenhouses are used for production of all types of plants for use at Denver Botanic Gardens. There is a continuous stream of plant material being produced for addition to our permanent collections, annuals for summer displays, potted plants for temporary exhibits in the Orangery and thousands of plants for our Spring Plant Sale. During the winter months, there are also a number of specimens from our bonsai collection on display in these greenhouses.
The Orangery is one of my favorite spots to spend a cold winter afternoon and having so many interesting distractions makes it all the better. We hope you'll come spend some time enjoying a break from the cold!
Photos by Nick Snakenberg