Garden Talk: April 19, 2012

From NGA Editors

A Titanic Flower

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The titan arum (Amorphophallus titanum) is one of the most spectacular plants around. This native of Indonesian rain forests grows from a corm that weighs over 200 pounds. Its flower is composed of a bloom stalk, or spadix, reaching as high as ten feet that's surrounded at its base by a three to four feet wide, frilly, bell-shaped cup called a spathe with a vivid maroon interior. Large doesn't mean long lasting, however. Three to four weeks after the bud tip first appears, the flower opens suddenly, with the spathe unfolding within a few hours, and then stays open less than 48 hours before collapsing.

While in bloom, it emits a powerful odor that has been likened to rotting fish with note of burnt sugar -- repulsive to us, but delectable to the carrion beetles and flesh flies that serve as pollinators in its native environment. This helps to explain another of the plant's common names -- corpse flower. To help spread its ″perfume″ the titan arum actually heats itself up by burning stored carbohydrates in order to volatilize its aroma and attract more pollinators. But the energy it expends in heat production accounts for its brief and infrequent blossoming, often with years going by between flowerings. If successfully pollinated, bright orange-red, cherry-sized berries are exposed when the spathe falls away. These are attractive to birds, which eat the berries and disperse the seeds inside.

When not in bloom, the titan arum maintains its titanic proportions, producing a single, umbrella-like leaf that can be 15 feet wide at the top of a thick stalk up to 20 feet tall in the wild. Only one gigantic leaf is produced each year, being replaced annually after a dormant period of about four months. It may take up to 15 years for plants to become mature enough to bloom.

Recently the corpse flower in the Department of Plant Biology's Liberty Hyde Bailey Conservatory at Cornell University bloomed. The entire flowering sequence was captured on time-lapse video. When the show begins, the spadix has reached its full height. Suddenly you see the spathe begin to unfurl -- surrounded by the hordes of people who braved the smell for a close-up view!

To watch Cornell's titan arum go through its bloom cycle go to: Cornell Cast.

Rhododendron of the Year

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Rhododendrons and azaleas (both members of the genus Rhododendron) have some of the loveliest blooms around, so it's not surprising that these shrubs are popular plants across the country. But there are so many different species and cultivars to choose from, and growing conditions vary so widely from one part of the country to another. How to choose the best members of this broad genus for your area?

The American Rhododendron Society helps with the selection process by offering its 2012 Rhododendron of the Year Awards. For each of eight geographic regions of the country -- Great Lakes, Mid-Atlantic, Northeast, Northwest, South Central, Southeast, Southwest, and Southern California-Hawaii -- the Society's Plant Award Committee has chosen four members of the Rhododendron genus, including an elepidote (large-leaved) and a lepidote (small-leaved) rhododendron and a deciduous and an evergreen azalea. (For the warm weather Hawaii/Southern California region, a vireya rhododendron has been selected.) Each plant selected displays excellent foliage and flowers, has an attractive plant habit, is hardy in the specific region, and is pest and disease resistant.

The American Rhododendron Society's website also offers information on growing and propagating rhododendrons and azaleas, a rhododendron blog, photo gallery, nursery finder and much more.

To find out more about the 2012 Rhododendron of the Year Awards, past winners, and all the American Rhododendron Society has to offer, go to: American Rhododendron Society.

Put Your Garden on the Map

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Gardeners are usually bird lovers as well as plant enthusiasts. Now you can combine both these interests in a citizen science project that's designed to give you a deeper understanding of the bird habitat your garden can offer and provide helpful information to professional scientists at the same time.

YardMap, a project of the Cornell University Lab of Ornithology that is funded by the National Science Foundation Informal Science Education Program, lets individuals across the country use satellite imagery to interactively draw maps of their yards and gardens, as well as parks, farms, school yards, and favorite birding spots. Be sure to watch the video on the home page first; it will make the mapping procedure clearer. The site offers suggestions for ways to make yards and gardens more bird-friendly. Find information about types of habitats, helpful landscape features and ideas for ways to improve bird habitat in a wide range of spaces, including a brand new home, a community garden, at the office, in the city, on a road median, or in an abandoned lot.

Scientists use the information collected to help them understand things such as what practices improve the wildlife value of residential landscapes, over how large an area these practices need to be implemented to be most effective, and the impact of urban and suburban wildlife corridors and stopover habitats on bird populations. YardMap is also an interactive citizen scientist network, connecting you to a like-minded community sharing strategies and successes on-line as they work to improve bird habitat.

To find out more about YardMap and get started on a map of your own yard, go to: YardMap.

The Strange Case of Barberry, Ticks, and Earthworms

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We've all probably heard about the problems caused by invasive plant species crowding out native vegetation and altering the ecosystem. But new research has shown that at least one invasive species is affecting the natural environment in unexpected ways and some of those changes may even be having an impact on human health.

Tom Worthley, assistant extension professor in the Department of Extension in the College of Agriculture and Natural Resources at the University of Connecticut, along with colleagues Scott Williams, adjunct professor in UConn's Department of Natural Resources and the Environment, and Jeffrey Ward, from the Department of Forestry and Horticulture at the Connecticut Agricultural Experiment Station in New Haven, are looking at ways to return the ecosystem of the University of Connecticut Forest in Storrs, now overrun with invasive Japanese barberry (Berberis thunbergii), to a more natural state.

In the process, they discovered that barberry has a negative impact on the forest ecosystem in some surprising and unexpected ways. It turns out that barberry provides the perfect humid environment for the ticks that carry Lyme disease and other tick-borne diseases. ″When we measure the presence of ticks carrying the Lyme spirochete (Borrelia burgdorferi) we find 120 infected ticks [per acre] where barberry is not contained, 40 ticks per acre where barberry is contained, and only 10 infected ticks where there is no barberry,″ says Scott Williams. And the barberry also provides a favored environment for mice, which act as vectors to spread the immature nymph stage of the ticks.

The introduced barberry also creates the perfect conditions to promote the spread of another introduced species that has a negative impact on forests -- the earthworm. Most folks are surprised to learn that earthworms are not native to northern regions of the U.S., including New England. The introduced worms gobble up the forest leaf litter, leaving the soil exposed. Says Jeffrey Ward, ″These worms have big appetites and when the litter layer gets eaten we see gullies forming, sediment washing into streams, soil chemistry changing -- all sorts of negatives that you don't see in a healthy forest ecosystem.″

To combat these problems, the researchers are working on developing practical and effective ways to control Japanese barberry in forested areas, including carefully targeted flame weeding.

To read more about this research, go to: UConn Today.

 
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