A ‘wet and wild’ walk at the Arboretum

Published 1:00 pm Wednesday, March 6, 2013

Were you the type to stomp in rain puddles as a child? If so, there’s a good chance you would have enjoyed visiting the Arboretum last Saturday, when eleven adventurous souls bravely forded the pooling water from recent rains on the field walk led by botanist Heather Sullivan from the Mississippi Department of Wildlife, Fisheries and Parks.

If you’ve only visited the Arboretum on “nice” days, you’ve been missing the exhilarating experience of feeling fully alive when the air is thick with moisture. Why, you can practically hear the trees growing on such a day! On Saturday, it was well worth enduring a little water for the opportunity to tag along with Heather, who proved once again to be a treasure trove of jaw-dropping stories about the plants we encountered.

It wasn’t long before we were rapidly soaking up facts. In her discussion of one of Mississippi’s most notorious invasive plants, cogon grass, we learned that in addition to being misbehaved, the blades of this colony-forming grass contain silica crystals that wear down the teeth of cattle that consume this plant. Also, volunteers to our coastal areas following Hurricane Katrina unknowingly brought cogon grass back home with them to northern climates, because fragments capable of reproduction “stowed away” on the undercarriages of their vehicles. Unfortunately, this greatly expanded its range. And although you might think that prescribed burning would eradicate this pesky grass, fire seems to encourage it, rather than deter it.

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Inkberry holly is common to both our Woodland and Savanna Exhibits. The leaves of this low-growing evergreen shrub contain volatile oils, which cause it to snap, crackle and pop during our prescription burns. However, winter burns don’t make much of a dent in stands of this plant. Heather pointed out that it takes a hot summer burn to keep this species plant under control.

Passing a sweetbay magnolia, Heather talked about the extensive damage which was sustained by this species as a result of the 2005 hurricane, and mused on the long time it will take to recover in areas such as in Forrest, Stone, and Jackson counties.

Rounding a corner, we spotted an American holly tree, and soon learned that prior to the production of plastics, its light-colored wood was used to fashion the white keys on a piano, along with “black” keys made from stained persimmon wood. These native woods were also much more inexpensive and available than the traditional “ebony and ivory”.

Coming upon a loblolly bay, Heather told us that this is one of two plant species in North American that are in the tea family. She has seen this tree growing in the Camp Shelby area. The other is silky camellia, or Stewartia, which many readers will know as naturally occurring on wooded slopes in Henleyfield.

A description by a walk participant about the many hummingbirds that had recently visited her yard led to Heather’s identifying the birds as rufous hummers, seen in the winter months. These birds will soon be travelling west, and “replaced” by ruby-throated hummingbirds. Diane Lafferty of Hattiesburg’s Pine Woods Audubon Society was soon providing nectar recipes for hummingbird feeders. One of the best things about our programs is just such an exchange of ideas that occur among the attendees.

Coming upon a specimen of the very cold tolerant needle palm provided us with a lesson on the difference between this species and the common saw palmetto. Look closely to see the narrow, sharp needles at the point where the leaves attach to the stem. Saw palmettos have leaf stems which are covered with sharp teeth, and are found in a wide variety of habitats, ranging from part to full sun, and dry sand scrub to wet pine woods. Needle palms prefer full to part shade, along with moist, well drained conditions. They can be found in areas such as the high bluffs of the Pascagoula River.

As we passed through the swamp forest area of the Pond Journey, which is located near our western site boundary and the interstate, someone pointed out the thick growth of lichens on the tree trunks we were passing. Heather told us that lichen growth is much denser in areas near well-travelled roadways, due to the carbon monoxide deposited on the tree bark from the nearby traffic.

In areas like the Arboretum’s swamp forest, compacted soils mean less oxygen is available to the roots of plants in this environment. The trees near roadways benefit from the deposited carbon monoxide. In wet soils, trees can be very shallow-rooted, perhaps with only a few feet of soil available which contains adequate oxygen for root development. In some areas, roots may need to travel to depths as great as six feet until they find soil that is not starved for oxygen.

In the days of leaded gasoline, lead was deposited on the trees which grew by the roadsides. Later, if the wood was harvested to use in building construction, it can later be a potential source of lead, if it is released during renovation projects.   

One of our big mysteries was solved on Saturday’s field walk. In our deck area on the east side of the pond, known as Cypress Cove, many of the bald and pond cypress growing here have peeling bark. At some times of the year, it is more noticeable than others, and we’ve wondered if this could be due to deer or other animals rubbing against the trees. But Heather said the peeling bark was a natural process which helps to accommodate tree growth, and also allows for tree respiration, or oxygen exchange.

To learn more secrets, attend our spring native plant sale on March 22 and 23 (Friday and Saturday) from 10 a.m. to 3 p.m. Admission is free. Plant professionals will be available to help you choose plants that fit your unique site conditions. Call the Arboretum office at 601-799-2311 for more information, or visit www.crosbyarboretum.msstate.edu.

The Crosby Arboretum is located in Picayune, I-59 Exit 4, at 370 Ridge Road (south of Walmart and adjacent to I-59).

For further exploration: See the Crosby Arboretum plant data base on our website to learn more about the plants mentioned above, especially unusual species such as loblolly bay and silky camellia.