Today we're celebrating a new addition to the Arboretum's collection: the Bulltongue Arrowhead. Unlike most specimens in the arboretum, arrowheads (genus
Sagittaria) are water plants. During the early days of the arboretum, permanent ponds were established to house a wide range of water plants. Within the past 15 years, the ponds were dismantled, which has resulted in a limited number of aquatic species in the collection.
These specimens were collected a year ago in a concrete spillway along North Hearne in Shreveport.
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| This bucket represents a culled portion of the formerly wild (but now cultivated) arrowheads collected from North Shreveport. |
Arrowheads are adaptable. Capable of reproduction through seed and rhizome spreading, the only thing arrowheads really require is nutrient-rich (i.e. polluted) water. Paralleling their versatile reproductive strategy, the arrowhead changes form based on its local conditions. When these plants were collected from the spillway, growing in a couple inches of scummy, shallow, flowing water, they were short and had narrow leaves. After they were transferred to a heavily shaded, clay-based manmade holding slough, the second growth form showed itself: tall plants with large broad leaves, resembling the 'bull's tongue' for which this species is named.
Standing water, flowing, or just very damp soil... full sun or mostly shade... the arrowhead is well-prepared for many environments. But beware! Rapid changes in conditions will kill this plant quickly.
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| Observe the two different kinds of roots: the long, fat, hollow spreading-root and the short, thin feeding-roots. |
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| Here you can see the plants separated into clumps. These clumps were all connected by a single root and are therefore likely one individual who had formed a colony. |
Because arrowheads are water-loving, they require, if not standing water, then at minimum a very damp area. This means only a few places in the arboretum are appropriate, and of those, only a few are "open for business." Here's one we found in the upper pond floodplain.
Although this area lacks standing water, it does recieve large amounts of water from the upper part of the arboretum, plus drainage from several surrounding structures, including the band shell and the Student Union Building. The soil here is damp and incredibly rich.
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| Here we have a natural clearing, mostly-shade, which the arrowhead can tolerate. |
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| The new additions are in the ground! |
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| The plants are sturdy, and hopefully they will adapt to their new location. |
The last step is to make sure that this area gets enough water in the remaining dry spells of late summer and fall. Let's dig a drainage trench to funnel water towards this area.
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| This trench will provide ample water flow to the arrowheads, even in cases of low rainfall. Of course, for the arrowheads to survive long-term, the trench will need to be maintained periodically. |
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| A tuxedo cat inspects our work. At the bottom of the frame, notice the backfill of loose earth to protect the arrowheads from heavy water flow. This may help them become established. |
