These plants live to eat bugs

Photos | Angela Underwood (l-r):  A purple pitcher plant; A damselfly caught by spoonleaf sundew.

By Nancy Adams, Mobile Master Gardener | [email protected]

If you live in South Alabama and have never visited one of the pitcher plant bogs in Baldwin County, you are in for a treat … another wonder of nature in which amazingly beautiful plants thrive in massive fields of nutrient-poor soil where few other plants could survive. The difference is that these are carnivorous plants, which trap and survive on nutrients from insects, spiders, crustaceans and other bugs.

Almost all carnivores grow in tropical areas or bogs, which differ from swamps in that bogs appear to be dry and swamps appear to be covered in water. In fact, bogs are also wet and mushy.

Joe Cuhaj of Baldwin County tells us that Splinter Hill Bog, managed by the Nature Conservancy in northern Baldwin County near the town of Perdido, is one of the most impressive pitcher plant bogs in Alabama, encompassing 2,100 acres known especially for its abundance of pitcher plants. These pitcher plants are in full bloom in July and August, and you can stroll on the boardwalks through the bog among these acres of gorgeous tubular plants at your leisure. And although the white-topped pitcher plants are the main attraction, the bog is also home to other carnivorous plants, along with a variety of colorful wildflowers.

Another bog open to the public is at Weeks Bay Reserve on Highway 98 near the Fish River Bridge. This bog holds more than 90 species of plants altogether, as well as several species of pitcher plants, and has become known locally for its unique splendor.

A plant is considered carnivorous only when it has at least one of the traits that allow it to attract, capture, digest and absorb nutrients from its prey. There are five basic trapping mechanisms used by the various carnivorous plants, and some use combinations of these. In summary, they are:

Pitfall traps: This mechanism, used by pitcher plants, attracts bugs and insects with sweet nectar; it has a slippery rolled leaf containing digestive enzymes that break down the prey to be absorbed by the plant. Sarracenia pitcher plant is often cultivated in the Southeast and is relatively easy to grow. Prey is attracted to the funnel-shaped leaves by smell and nectar and will fall into the trap.

In the Darlington californica, also known as the cobra plant, the operculum, which covers and protects the rolled leaf from the rain, balloons out to resemble a cobra and folds over to almost seal the tube opening. Insects enter the opening under the balloon and fall into the tube.

Another interesting carnivore with a pitfall trap is a bromeliad called Brocchinia reducta. Related to the pineapple, this has thick, waxy leaves that form an urn that easily collects water, attracting frogs, insects and nitrogen-supplying bacteria.

Bladder traps: Bladderworts (Utricularia) create a partial vacuum inside the bladder by pumping out ions. Water follows by osmosis. Through the process, trigger hairs are touched by prey, leading to their being pulled into the bladder and digested.

Lobster-pot traps consist of a Y-shaped leaf where the insect enters, followed by hairs that pull it further inward, similar to the bladder trap mechanism.

Flypaper traps are sticky, like glue, and have long or short glands containing a glue-like substance to trap the prey. An example of the flypaper trap is Drosera, the sundew genus, found on almost all continents and having fast-growing mucilage glands on long tentacles for capturing prey. There are more than 100 species of active flypapers and they depend on trapping insects for nutrients.

Snap traps: Venus flytrap (Dionaea muscipula) and the waterwheel plant (Aldrovanda vesiculosa) are two active snap traps. Although Dionaea is terrestrial and Aldrovanda is aquatic, the traps work the same. There are leaves divided into two lobes, connected in the middle with trigger hairs that, when bent, allow the lobes to snap shut, trapping prey. Interestingly, the Venus flytrap can distinguish debris or raindrops and only shuts on actual prey.

When you take a morning or afternoon to stroll on the boardwalk through a bog in Baldwin County, particularly in July or August, you may not be able to distinguish many — or any — of the trapping mechanisms used by the carnivorous plants, but I believe you will thoroughly enjoy the experience and will walk away with an enhanced appreciation for yet another amazing wonder of nature.

GARDENERS, CHECK THIS OUT:

What: Mobile Master Gardeners monthly meeting
When: Thursday, Aug. 2, 10-11:30 a.m.
Speaker: Terry Plauche, Urban Oases — Green Areas in Metro Areas

What: Mobile Master Gardeners Lunch & Learn
When: Monday, Aug. 20, noon to 1 p.m.
Speaker: Larissa Graham, Groundwork-Mobile County, Student Conservation Association

What: Landscaping 101
When: Aug. 27 & 28, 6-8 p.m.; call 251-574-8445 to register
Topic: Learn how to have a beautiful yard and save money
Speakers: Urban Regional Extension Jack Lecroy and Regional Extension Agent Evan Ware

Master Gardener Helpline: 1-877-252-4769 or send gardening questions to [email protected]