Enhancement of Natural Dune Building and Revegetation
Processes on Santa Rosa Island
Research Work Order 159
Deborah L. Miller
West Florida Research and Education Center
University of Florida
P.O. Box 3634
Milton, FL 32572-3634
Phone (850) 983-2632
In October 1995, Hurricane Opal's 12-15 foot storm surge leveled extensive
sections of sand dunes in the Florida panhandle. Sand dunes provide critical habitat for
the Santa Rosa beach mouse (Peromyscus polionotus leucocephalus) and serve to
protect sea turtles as well as providing coastal protection from storm surge (Woodhouse
1978, Salmon et al. 1982, Gore 1993). Fragmentation of the dune system on Santa
Rosa Island, the barrier island most impacted by the storm, may pose a threat to these
populations. Methods to facilitate reestablishment and stabilization of dunes in
hurricane created gaps are beneficial if the functional role of the dune system is more
Sand fence of different types has been used to enhance sand accumulation on
other coasts (Woodhouse 1978, Hotta, et al. 1991, Mendelssohn et al. 1991). Except
in areas with strong wind conditions, a single fence has been found to be more efficient
than double fences (Woodhouse 1978, Hotta, et al. 1991). Straight sand fence was
shown to accumulate sand more effectively than side spur or zig zag (oblique) fence
configurations on Timbalier Island, Louisiana over a three year study period
(Mendolssohn et al. 1991). However, in other studies a straight fence configuration
was found to be less effective where strong winds occasionally blow parallel to the
fence (Woodhouse 1978). This suggests that recommendations of sand fence
configuration should be developed for specific sites as field conditions vary from site to
Synthetic fabrics of appropriate porosity (around 50%) have performed
similarly to wooden slat fence in accumulating sand (Woodhouse 1978). However,
biodegradable materials are preferred for sand fence construction as nonbiodegrable
material may present a hazard for burrowing animals. Geojute fabric, a product
frequently used in erosion control, is biodegradable, less expensive than wood fence
and has a porosity appropriate for sand accumulation. Evaluation of Geojute as an
alternative to the commonly used wooden sand fence would establish if this product can
be used as an efficient fence material for dune restoration.
Dune restoration utilizing sand fence has generally concentrated on fore dune
areas (Dahl, et al. 1975, Hotta, et al. 1991). Interior dunes provide the largest area of
Santa Rosa beach mouse habitat on Santa Rosa Island and mice on interior dunes are
less susceptible to destruction by severe storms (Gore and Schaefer 1992). Areas with
less impact from Opal's storm surge on Santa Rosa Island had a well-developed
secondary dune system prior to the storm. Restoration of secondary dunes may be more
important for protection of the Santa Rosa beach mouse and future stability of the dune
system. Therefore, recommendations for restoration of the secondary dune system of
the Florida panhandle is important.
In addition to sand accumulation, stabilization of the dunes against further
storms should be an ultimate goal. Vegetation assists in trapping sand and is essential
for dune stabilization (Dahl and Woodard 1977, Woodhouse 1978, Salmon et al.
1982). Plant recolonization following large storms or beach nourishment projects may
be slow (Cousens 1988, Mendelssohn et al. 1991, Gibson and Looney 1992, Morton et
al. 1994). Sea oats (Uniola paniculata) and bitter panicum (Panicum amarum) are
frequently planted for dune restoration because they are adapted to harsh beach
conditions (salt spray, low soil nutrient content, low soil moisture, sand abrasion, etc.)
and have deep fibrous roots that function to efficiently trap and stabilize sand (Dahl et
al 1975, Davis 1975, Dahl and Woodard 1977, Woodhouse 1978, Salmon et al. 1982).
To create an even and stable area of sand accumulation, interplanting the two species is
generally recommended for the Gulf Coast (Woodhouse 1978, Salmon et al. 1982).
Recommendations for the most appropriate time to plant sea oats and bitter
panicum vary. Barnett and Crewz (1997) suggest a planting window of March through
November, for Florida sites north of Tampa. However, summer planting requires
supplemental watering due to high evapotranspiration rates (Dahl, et al. 1975, Dahl
and Woodard 1977, Woodhouse 1978, Stout 1993, Barnett and Crewz 1997). Dahl, et
al. (1975) reported that sea oats and bitter panicum may be planted on the Gulf Coast
any time there is sufficient soil water and low salinity; and others have recommended a
cooler season (between late fall to early spring) as the best time to plant (Dahl and
Woodard 1977, Woodhouse 1978, Salmon, et al. 1982, Americus Plant Center 1992,
Stout 1993). Supplemental watering may be eliminated if planting late fall/early
winter when the rate of evapotranspiration is lower, thereby reducing the effort and
resources required for dune restoration.
Post-Opal, large quantities of sea oat rhizomes were found uprooted and
exposed to the elements. These rhizomes represent a potential propagule bank for
beach revegetation. Following storms, the initial recolonization of beaches by sea oats
has been reported to occur from intact extant rhizome material (Cousens 1988).
However, the potential for revegetation by reburial of sea oat rhizomes uprooted by
storms remains undocumented. The viability of uprooted rhizomes should diminish
with time of exposure to desiccating wind and salt spray. The relationship between
viability and time of exposure has not been quantified. Given the large quantities of
uprooted rhizomes available for replanting following a storm, revegetation by rhizome
plantings appears to be an important unexplored restoration technique.
To increase stabilization and diversity, native woody species have been
recommended for revegetation of coastal dunes (Davis 1975). Yar (Casurina
equisetifolia) has been used to stabilize dunes successfully in West Africa (Linehan,
personal communication). Cousens (1988) observed that rosemary (Ceratiola
ericoides) was equal to sea oats in stabilizing dunes blown apart by Hurricane Frederic
on Perdido Key, Florida. Woody species commonly found on the secondary dune
systems of Santa Rosa Island include: rosemary (Ceratiola ericoides), myrtle oak
(Quercus myrtifolia), sand live oak (Quercus geminata), yaupon (Ilex vomitoria), and
slash pine (Pinus elliottii). Evaluation of these species for their viability as dune
restoration species on Gulf Coast sites would provide information that is not available.
Of the species listed, rosemary is the only species not commercially available and
evaluation of this species first requires development of propagation and production
Rosemary (Ceratiola ericoides) is a woody, evergreen, dioecious shrub of the
Empetraceae (Crowberry family) endemic to the coastal and xeric areas of Florida,
Georgia and South Carolina (Godfrey 1988). Rosemary is a dominant dune binding
species of the barrier islands of Florida and has been the subject of an extensive
population structure study to determine the spatial pattern, age, sex and size structure
of four populations in Florida (Gibson et al. 1994). These populations were shown to
have a male to female sex ratio of 1:1 and the mean age of reproductive individuals
was 13 to 16 years for coastal populations. The uniform, globose canopy and dark,
evergreen foliage of rosemary also make it extremely desirable as a home landscape
plant in the barrier island communities. Rosemary production has not been possible on
a commercial scale because seed germination is slow and difficult and no vegetative
propagation information is available (Johnson 1986).
Objectives of this study were: 1) to evaluate the effects of sand fence orientation
(straight-conventional, straight-perpendicular and oblique) and material (Geojute or
wood) on sand accumulation in the secondary dune position, 2) to determine the effects
of late fall and spring planting seasons on sea oat and bitter panicum survival and
growth, 3) to assess the technique of planting uprooted sea oat exposed to the elements
for varying lengths of time, 4) to evaluate the viability of planting several different
woody species for revegetation of dunes, 5) evaluate the effectiveness of common
auxin sources on the rooting of rosemary, 6) evaluate the influence of two propagation
substrates on the rooting response of rosemary 7) determine if the sex of the cutting
influences rosemary rooting response, and 8) to determine if pinebark based substrates
are suitable for the production of rosemary.
The study was located on property owned by Eglin Air Force Base on Santa
Rosa Island, Florida east of Navarre Beach (30 0 18' N, 87016' W) (Figure 1). This
portion of the island has historically maintained one of the most stable shorelines along
the entire Northeastern Gulf Coast (Otvos 1982). The western extent of the property is
separated from the mainland by Santa Rosa Sound (width approximately 0.50 km),
while Choctawhatchee Bay (width approximately 5 km ) backs the eastern extent.
Figure 1. Map of Florida with insert showing the location of Eglin Air Force Base and
Santa Rosa Island. T indicate the location of the six replicate sites.
Santa Rosa Island is a Holocene barrier island supplied by sediment west of
Shell Island, Florida (Stone and Stapor 1996). Soils of the island are almost 100%
pure quartz sand with a median diameter of approximately 0.25mm (Wolfe et al.1988).
The mosaic of coastal dunes and swales on the island support four major plant
communities: coastal interdunal swale, mesic flatwoods, scrub, and beach dunes
(Kindell, et al. 1997).
The island has a mild, subtropical climate, influenced by the gulf with mean
annual precipitation of 152 cm, rainfall and peaks in summer and late winter /early
spring. From September-February winds are prevalently out of the north while
prevailing southerly winds occur for the remainder of the year. Mean monthly wind
strength is higher in the fall, winter and spring than during summer months.
Study sites were positioned on level overwashed areas which were beach dunes
prior to Hurricanes Opal and Erin. Typical vegetation of intact or fragmented dunes
includes Ceratiola ericiodes, Hypericum reductum, Uniola paniculata, Spartina patens,
Baludina angustifolia, Paronychia erecta, Cakile constricta, Chrysoma
pauciflosculosa, Chrysopsis godfreyi, Conradina canescens, Ipomea pes-caprae, Iva
imbricata, Oenothera humifusa, Panicum amarum, Physalis angustifolia,
Schizachyrium maritimum, and Smilax auriculata.
Sand fence of 3 configurations (straight-conventional, straight-perpendicular and
oblique) and two materials (wood and Geojute) were installed at six replicate overwash
sites (dunes leveled and little remaining vegetation), each at least 2.5 km long. The
wood fence consisted of 3.8 cm by 1.2 m high wooden slats bound together with steel
wire. The Geojute fabric was 1.2 m wide and both materials had a porosity of 50 %.
PVC pipe (schedule 40; 1.83 m high and 5 cm diameter) was driven into the sand
about 0.6 m to ensure stability (Figs. 2 and 3). Plastic ties were used to connect the
fence material to the PVC pipe. The following three configurations were used: 1)
straight-conventional sand fence placed parallel to the shore, 2) straight-perpendicular
- sand fence placed parallel to the shore with a 3 m perpendicular spur spaced at a 5 m
interval along the northern side of the fence, 3) oblique sand fence placed in
alternating diagonal pattern to the shore. Each fence material/ orientation combination
(treatment) within each site is 45 m for a total of 270 m of fence per site with an
additional 45 m of nonfenced beach to serve as a control. Treatments were randomly
placed in line with the remaining secondary dunes system, approximately 100-120 m
from the mean high tide line.
Plantings in association with fence treatments
Fence treatments and the unfenced control were divided into three sections and
a seasonal planting of sea oats and bitter panicum was randomly assigned to each of
two sections. The remaining section (control) was not planted. Plants were planted on
the Gulf side in 6 rows starting 1 /2 m from the fence spaced 1 m apart, alternating
species. For each season, thirty eight plants of each species were planted for each
treatment (including unfenced controls) at each replicate site for a total of 1596 of each
species per season.
Sand Live Oak
Large Gallberry (Holly)
Figure 2. Sand fence configuration, alignment and position of fence and plants in relation to the
Gulf and Bay.
2.5 m 2.5 m
Figure 3. Location of PVC pipe and dimensions for construction of a single 5 m section for three
configurations of sand fence.
Sand accumulation was measured using a level and stadia rod. The eastern
most pole for each fence treatment was established as the benchmark for recording
elevation measurements. Beginning 1 m west of the eastern end of each fence
treatment, positions were marked with flags every 5 meters at 1, 6, 11 and 16 m north
and south of the fence (Bay/Sound and Gulf sides). Elevation was measured at all
flagged locations and midway between all flags of the first row (1m) and midway
between the flags on the first and second row (6m) from the fence. Sand accumulation
or loss was determined by change in elevation relative to the benchmark for each
treatment. A baseline elevation was determined August- September 1996 and
accumulation /loss was measured November 1996, February-March 1997, November
1997, March-April 1998 and November-December 1998.
Sand Accumulation Statistical Analysis
The sand accumulation experiment was a randomized block, split plot design
with sites as blocks, fence type/orientation as main treatments and season of planting
as splits. Because adjacent fences noticeably affected sand accumulation for
treatments, elevation measurements taken from within 6 m west of the easternmost
end and 4 m east of the westernmost end of the treatments were removed from the
analyses. All other sand accumulation data were treated as subsamples for each season
of planting. For each date, separate analyses were performed for each distance from
the fence for the Bay/Sound and the Gulf side. Season of planting did not significantly
affect sand and was removed from the analyses. Final reported analyses used a
randomized block design with sites as blocks and fence types as treatments. Mean
separations for each fence treatment were performed using the Bonferroni multiple
Seasonal Planting of Sea Oats, Bitter Panicum and Woody Plants
To determine seasonal effects on survival and growth of planted sea oats and
bitter panicum, seedlings (10 cm liners) were planted December 4-6, 1996 and March
18-19, 1997 (see description above). Plant survival was evaluated October 1997.
Length of the longest leaf, basal width, tiller number, and inflorescence number were
measured for surviving plants per season of planting per fence treatment. Woody
species (126 plants per species per date) including sand live oak, myrtle oak, slash
pine, yaupon holly, inkberry and rosemary were planted on the bay/sound side of the
fence treatment in December and March.
The season of planting experiment was designed as a randomized block, split
plot design with sites as blocks, fence type/orientation as main treatments, and season
of planting as a split plot. However, sand accumulation near the fence was different
for fall and spring plantings, and percent survival for both species was correlated with
the initial elevation at the time of planting. Consequently, to isolate the effects of
season of planting and remove the confounding effects of the fence treatments, an
analysis of variance was performed using only the survival values for the control
treatments (unfenced sections). Elevation in control sites did not differ between
seasons (significant sand accumulation did not occur). Similar analyses were
performed for the growth variables measured.
Uprooted Sea Oat Rhizome Experiment
1996 Experiment. Experiments were performed to determine viability of sea oat rhizomes
uprooted, immersed in seawater and exposed to the elements for varying lengths of time.
For each month from June October 1996, sea oat rhizomes were uprooted, sorted into
four groups culmm, 1 node, 2 nodes, and 3 nodes), and immersed in the Gulf for 5
minutes. Following immersion, rhizomes were wrapped in a net and exposed to the
elements on the beach for 1, 3 or 7 days before planting. Five rhizomes of each type were
randomly assigned to each exposure time for each uprooting time (month). Rhizomes
were randomly planted, on lm center in 6 rows, approximately 50 m inland from the
mean high tide at a depth of 25 cm.
Tiller emergence was recorded weekly through November 1996 and monthly
thereafter. Simultaneously, a pot experiment utilizing the same treatments described
above was initiated to determine rhizome viability under optimum watering conditions.
Rhizomes were planted approximately 5 cm deep in 3.8 liter plastic pots. Pots
contained 5 cm of pine bark to prevent the overlying beach sand from washing out
when watered. Pots were placed outside at the West Florida Research and Education
Center, Jay, Florida where they received water weekly.
Field and pot experiments had a factorial arrangement of treatments with
rhizome type (4 levels), exposure times (3 levels) and uprooting times (months) as
main factors. As the data had a binomial distribution, analyses were performed using a
generalized linear model based on the Chi-square distribution. Due to the large
number of non-emergence for some treatments in the beach experiment a second
analysis was performed for this experiment. Data was combined across months for
each rhizome type and exposure time and treatment effects for rhizome type and
exposure time were evaluated using a generalized linear model. Contrast statements
were used to determine differences between rhizome types.
1997 Experiment. For each month from June-October 1997, 3 node rhizomes were
planted in pots and on the beach after 3, 5 and 7 days of exposure. Additional 3 node
rhizomes were exposed for 3 and 5 days, wrapped in wet burlap and planted 5 and 7
days after the initial uprooting. These modifications were based on results of 1996
experiments. Each month, six rhizomes were randomly assigned to each exposure
treatment. Tiller emergence was recorded weekly through November 1997 and
Rhizomes were not planted for the July day 5 exposure treatment due to
Hurricane Danny. Field and pot experiments had a factorial arrangement of treatments
with exposure times (6 levels) and uprooting times (months) as main factors. A
generalized linear model based on the Chi-square distribution was used for analysis.
July data was excluded from the analysis, as it was incomplete.
1998 Experiment. To determine if watering would increase viability of beach planted
rhizomes, the 1997 experiment was modified as follows. July 1998, 3 node rhizomes
were randomly assigned to watered and unwatered sections 75 m from the mean high
tide line (1 m centers, 6 rows) on the beach after 3, 5, 7, 9 and 11 days of exposure.
Additional 3 node rhizomes were exposed for 3 and 5 days, wrapped in wet burlap and
planted 5 and 7 days after initial uprooting. Rhizomes assigned to the watered section
received water at time of planting and weekly thereafter. Tiller emergence was
recorded weekly through September 1998. The experiment had a factorial arrangement
of treatments with watering level (water or unwatered) and exposure times (7 levels) as
main factors. Twenty rhizomes were randomly assigned to each treatment. Treatment
effects were analyzed using a generalized linear model based on a Chi-square
distribution. Because there was an interaction between watering level and exposure,
effects of exposure times could not be separated using the previous model. Emergence
was analyzed for the watering treatments separately.
Hurricane Georges. September 27 and 28, 1998, the storm surge from Hurricane Georges
uprooted sea oat rhizomes on Santa Rosa Island. Three days after the surge, fifty 3 node
rhizomes were collected, wrapped in wet burlap for two days and planted on the beach.
Five days after the storm surge, fifty 3 node rhizomes were collected and planted on the
beach. Twenty-five rhizomes from each exposure treatment were randomly assigned to a
watered or unwatered section of the beach (similar to July uprooted plants). Experiment
had a factorial arrangement of treatments with exposure times (2 levels) and watering
level (watered or not watered) as main factors.
Softwood cuttings of rosemary were collected on July 23, 1996 from the eastern
end of Santa Rosa Island. Cuttings were segregated by sex, placed in plastic bags, and
stored in a cooler for transport. Prior to treatment, cuttings were recut to a length of 9
cm and the foliage removed from the basal 4 cm of each cutting. Auxin treatments
included Hormodin 1 and Hormodin 3, commercially available talc formulations
containing 3,000 and 8,000 ppm Indole-3-butyric acid (IBA), respectively; IBA at
1,000 or 5,000 ppm; 1-Naphthaleneacetic acid (NAA) at 1,000 or 5,000 ppm; Dip'N
Grow (10,000 ppm IBA and 5,000 ppm NAA stock solution) diluted with distilled
water at three ratios: 1:5 (1666.66 ppm IBA and 833.33 ppm NAA), 1:10 (909.09 ppm
IBA and 454.54 ppm NAA), and 1:20 (476.19 ppm IBA and 238.09 ppm NAA), and a
nontreated control. Both NAA and IBA were each dissolved in isopropyl alcohol.
Dilution ratios of Dip'N Grow were selected on the basis of label recommendations.
The basal 1 cm of each cutting was treated with an auxin solution for 1 sec followed by
15 min of air drying prior to insertion to a 2 cm depth in a 10 cm deep nursery flat
containing a medium of perlite:vermiculite (1:1 by volume) or 0.625 cm pinebark:sand
(6:1 by volume). Intermittent mist operated 6-8 sec every 10 min from 7 a.m. to 8
p.m. daily and cuttings were maintained under natural photoperiod. Cuttings were
sprayed on a biweekly schedule with Daconyl to control fungal diseases. The
experimental design was a split, split plot arranged in a randomized complete block
with six cuttings per auxin treatment (a total of 40 treatments) and ten replications. The
experiment was terminated after 12 weeks and percent rooting, root number, and
length of the 5 longest primary roots > 1 mm recorded. Mean separation within main
effects of propagation substrate, sex and auxin treatment were determined using the
least significant difference test at an alpha level of 5%.
Liners (rooted cuttings) from the previously described experiment were potted
into 1 quart containers using production substrates composed of pinebark:sand (6:1
v v) or pinebark:peat:sand (6:1:1 vj v jv). The production substrates contained 2.9 kg
dolomitic limestone, 0.88 kg micromax (microelement fertilizer) and 2.9 kg Osmocote
18-6-12 slow release fertilizer (8-9 month formulation) per cubic meter. Liners were
categorized on the basis of cutting sex and propagation substrate resulting in four
distinct groups; Female or male cuttings rooted in perlite:vermiculite and female or
male cuttings rooted in pinebark:sand. Plants received no supplemental fertilization, no
pesticide applications and were irrigated as needed. Plants were evaluated in October
for survival, shoot height, shoot number, and shoot number increase (secondary
branching from the base).
Results and Discussion:
Three months after fence installation, increased wind velocity attributed to
tropical storm Josephine (landfall October 8, 1996 near Apalachicola, Florida) resulted
in a range of 20-95 cm of sand accumulation 3 m either side of the fence (Fig. 4). On
average, unfenced controls lost elevation. Throughout the next 1.5 yrs, sand continued
to accumulate, increasing the width and height of the "created" dunes associated with
the sand fence (Fig. 5-8). Wood fence (all configurations) had significantly higher sand
accumulation compared to controls to a distance of 3.5 m and 1 m, bay/sound and gulf
side of fences, respectively for most dates (Tables 1 and 2). Although not significantly
different from controls, sand accumulation in association with fence treatments was
recorded to a distance of 6 m on the Gulf side of fences (November 1996 March
1998) and to 11 m (the max. distance measured from the fence) 2 years following
installation (October 1998). On the bay side accumulation did not reach 6 m until
November 1997 and 11 m in October 1998.
Initially, (year 1) the crest of sand accumulation was found on the Gulf side of
fences. However, for the remainder of the study the greatest accumulation was found
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on the bay side of fences. Thirty months (2.5 yrs) after fence installation, maximum
accumulation was found 1 m from the wood fence on the bay/sound side with
maximum values of 110 cm and minimum values of 69 cm. Accumulation in the
control plots was greater on the Gulf side.
Geojute performed well for approximately 8 months with no significant
differences in accumulation between materials for most positions (Fig.4-6, Table 1 and
2). However, the material degraded rapidly and accumulated sand was lost. Eighteen
months (1.5 yrs) after installation (fall 1997), Geojute no longer had significantly more
accumulated sand than the controls (Fig. 7- 8,Table 1 and 2). This material does not
appear suitable for dune restoration projects. For wood fences, sand accumulation did
not differ significantly among fence configurations at most distances from the fence.
However, through time the straight -conventional wood and perpendicular -wood fence
treatments more consistently had significantly higher sand accumulation values
compared to unfenced controls 3.5 m on the bay side of the fences. In Louisiana,
Mendelssohn et al. (1991) observed greater sand accumulation after 2 years with
straight and oblique fence treatments compared to straight fences with perpendicular
side spurs. However, after three years the straight sand fence design exceeded the
other designs. This study was conducted at one location (305 m) on a barrier island
and did not encompass the variation that might occur across an island. Under most
wind conditions, Woodhouse (1978) recommended using a straight fence configuration
compared to other configurations.
Regardless of fence material or configuration, plantings of sea oats and bitter
panicum did not significantly effect sand accumulation. However, any significant
impact plantings may have on elevation changes may not be detectable until plants have
gained sufficient size to become a contributing part of sand accumulation and
stabilization. Elevations will be assessed in March 1999 and possible effects of planting
sea oats and bitter panicum may be detectable at that time.
Although buried and not visible until 1997, the small amount of sea oats and
bitter panicum not uprooted by Opal recovered rapidly. Extant plants were larger than
transplants and began contributing to sand accumulation across all sites by 1997.
Hurricane and tropical storm activity in the Florida panhandle has been frequent
over the last 5 years. After installation of the fences, several storms including
Hurricane Danny (3-5 ft tidal surge) (1997) and Georges (5-8 ft tidal surge) (1998)
impacted the beaches. The position of the experimental sites on the beach (100-120 m
from the high water line) has allowed for continued dune building with minimal
negative impact from these storms. In fact, at some sites the winds associated with
tropical storm activity have enhanced sand accumulation. Hurricane Georges
(September 1998), the strongest storm since Opal, overwashed much of Santa Rosa
Island. Fenced sites were generally little impacted by the storm.
Planting of Sea Oats and Bitter Panicum
Fence effects. In fenced areas, elevation was correlated with season of planting
(p=.0001). In addition, survival of transplants was negatively correlated with
elevation (sand accumulation) at time of planting (p=.0001). Therefore, decreased
survival between seasons of planting may have been associated with the higher initial
planting elevation. In addition, because Choctawhatchee Bay (associated with the
eastern sites) is a wider body of water compared to Santa Rosa Sound (associated with
three western sites), wind speed appeared to be greater on eastern sites. Sites
associated with Choctawhatchee Bay (eastern three sites) had the greatest sand
accumulation prior to planting as a result of Tropical storm Josephine (up to 6 m from
fence mean elevation on Gulf side range from 4-72 cm eastern sites; -19 to 24 cm
western sites). Eastern sites had a lower percent plant survival (p= .0001) (17-47% sea
oats; 6-40% bitter panicum), particularly in the three rows nearest the fence while
western sites had survival rates of 62-92% and 30-91% for sea oats and bitter panicum,
respectively (Table 3). The greatest cause of transplant mortality was from excavation
by wind; thus survival was greatest where initial elevation was diminished and sand
movement was reduced. Because of environmental conditions (unstable substrate and
low moisture) planting sea oats or bitter panicum near fences after appreciable sand
accumulation has occurred (greater than 30 cm) resulted in poor survival. Dahl (1975)
reported similar problems associated with planting in conjunction with fences.
Season of planting. Because of the confounding effect of elevation associated with
fences, differences in growth and survival between late fall and spring planting dates
were assessed for control plots only (no significant elevation difference existed between
planting dates). Percent survival of sea oats and bitter panicum did not differ
significantly between seasons (Table 4). However, tiller number, basal width, number
of inflorescence and height of bitter panicum were greater for spring plantings. Spring
planted sea oats had greater basal areas and height than those planted in late fall.
Regardless of time of planting, sea oats did not produce inflorescence.
Survival of sea oats and bitter panicum regardless of location or fence
treatments was 54% (fall) and 62%(spring) which was higher than the 25% and 16%
Table 3. Percent survival of sea oats and bitter panicum planted in Fall, 1996 and spring, 1997.
Santa Rosa Island
Perpendicular Geojute Eastern Sites 18 47 16 37
Western Sites 75 86 63 73
Perpendicular Wood Eastern Sites 17 37 10 30
Western Sites 67 72 30 80
Straight Geojute Eastern Sites 40 43 6 37
Western Sites 89 87 46 91
Straight Wood Eastern Sites 23 14 21 6
Western Sites 62 75 50 74
Table 4. Mean percent survival, ramet number, tiller number, basal width (cm), height (cm) and number of
inflorescence of sea oats and bitter panicum planted in unfenced controls.
% Ramet Tiller Basal Width Height Inflorescence
Survival number Number (cm) (cm) Number
Fall 79.40 1.00 3.00 1.83 58.89 0
Spring 84.20 1.00 4.00 2.76 69.86 0
p- value 0.7229 0.1839 0.0925 0.0259 0.0024 n/a
Fall 66.40 1.00 5.00 2.19 34.42 1.00
Spring 82.40 1.00 9.00 5.20 51.37 4.00
p- value 0.3018 0.4838 0.0019 0.0002 0.0001 0.0001
reported in North Carolina and Louisiana and within the range of survival reported in
Texas (5-68%) (Seneca et al., 1976, Mendelssohn et al. 1991, Dahl et al., 1975).
Overall survival rate (fenced and unfenced areas) for bitter panicum 35 % (fall) and
60% (spring) was lower than the (76%) reported in Louisiana however, rate of survival
for control areas in our study (79% and 84%) was comparable to those reported for
Louisiana, Texas (10-70%) and North Carolina 62%.
Plantings of Woody species
Plantings of woody species were unsuccessful. For all species, soon after planting all
top growth was defoliated. However, all species produced additional new leaves.
Myrtle oak and sand live oak produced new flushes of basal sprouts for two growing
seasons. Subsequently most plants were buried or excavated as a result of tropical
storm, hurricane and cold front activity. The greatest losses of woody species resulted
from a lack of acclimation to the salt spray. Secondary losses occurred as a result of
burial associated with dune building and the seasonal shifting of accumulated sand.
Development of salt acclimation procedures would facilitate the use of this technique
for stabilizing "created" dunes.
Uprooted Sea Oat Rhizome Experiment
1996 Experiment. Mean survival (across dates) for 3 node rhizomes planted in pots
and on the beach after 1 day of exposure was 72% and 28%, respectively. For most
months, rhizomes replanted on the beach with no subsequent watering had lower
survival than those planted in pots with subsequent watering (Tables 5 and 6). Survival
generally declined with increasing length of exposure (beach p= .0001; pots p= .0001)
and decreasing size of rhizome (beach p =.0008; pots p=.0001). For most months
Table 5.Percent emergence of sea oat rhizomes culmm, 1, 2, and 3 node rhizomes)
uprooted on Santa Rosa Island, Florida, immersed in sea water and planted after 1, 3
and 7 days of exposure in pots which were watered weekly for June-October 1996.
Culm I Node 2 Nodes 3 Nodes Total
Dayl 0 0 40 80 30
Day 3 0 0 0 0 0
Day 7 20 0 0 0 5
Dayl 20 0 60 100 45
Day 3 60 20 20 80 45
Day 7 0 0 0 0 0
Day1 20 20 60 80 45
Day 3 60 0 20 60 35
Day 7 0 0 0 20 5
Day 60 80 40 80 65
Day 3 20 0 20 40 20
Day 7 0 0 0 20 5
Day 20 0 40 20 20
Day 3 0 0 20 0 5
Day 7 0 0 20 0 5
Table 6. Percent emergence of sea oat rhizomes culmm, 1, 2, and 3 node rhizomes)
uprooted on Santa Rosa Island, Florida, immersed in sea water and planted after 1, 3
and 7 days of exposure on the beach of Santa Rosa Island for June-October 1996.
Culm 1 Node 2 Nodes 3 Nodes Total
Day1 20 0 20 40 20
Day 3 0 0 0 20 5
Day7 0 0 0 0 0
Day1 20 0 20 40 20
Day 3 0 0 20 20 10
Day 7 0 0 0 0 0
Day1 0 0 20 40 15
Day 3 0 0 0 0 0
Day 7 0 0 0 0 0
Day1 20 0 0 40 15
Day 3 0 0 0 20 5
Day 7 0 0 0 0 0
Day1 0 0 40 20 15
Day 3 0 0 0 20 5
Day 7 0 20 0 0 5
and rhizome sizes, when air exposure time was greater than 3 days, less than 5% of the
potted rhizomes survived and 0% of beach planted rhizomes survived.
1997 Experiment. Generally, percent survival of three node rhizomes was greater in
1997 when compared to 1996 (Table 7). In some months, a small percentage of
rhizomes survived the longest exposure times (7 days) when planted on the beach or in
pots. After three days of exposure, mean survival (across dates) in pots and on the
beach was 40% and 50%, respectively. After 7 days of exposure mean survival was
40%, 10%, 15% and 17% for potted rhizomes, beach planted rhizomes, burlap treated
after 3 days and burlap treated after 5 days, respectively.
1998 Experiment. The 1998 experiment was conducted in July only, larger rhizome
numbers (compared to other years) were planted with all plants placed on the beach.
The maximum exposure time was extended to 11 days. Half of these plants were
watered while half were not. For watered plants, 80% survival after three days of
exposure was greater than that of all other exposure times (p=.0001) (Table 8).
Survival of unwatered plants did not vary with exposure time (p= .4121). After 11
days of exposure survival was 20%. Burlap did not increase survival for either
watered or unwatered treatments.
Hurricane Georges treated rhizomes (1998). Although rhizomes were exposed to the
elements for 5 days after Hurricane Georges, survival ranged from 32-48% (Table 9).
Watered rhizomes did not survive better than those without water and burlaped treated
plants survived equally well.
Table 7. Percent emergence of sea oat rhizomes uprooted, immersed in sea water for five minutes and
planted in pots (watered) or on Santa Rosa Island beach (not watered) after 3, 5, and 7 days of exposure and
rhizomes wrapped in wet burlap after 3 or 5 days and planted 5 or 7 days after uprooting for June-October
1997. Danny indicates that rhizomes were not planted for those treatments due to Hurricane Danny.
Asterisk (*) indicates that only 2 rhizomes were planted for that treatment and month for all other treatments 6
rhizomes were planted.
Days of Exposure June July August September October Total
3 50 33 50 50 67 50.00
5 100 Danny 17 33 33 45.75
7 50 33 50 0 67 40.00
5/ Moist after 3 Days 50 Danny 67 17 17 37.75
71 Moist after 3 Days 100* 33 33 83 100 62.25
7/ Moist after 5 Days 67 Danny 0 33 67 41.75
3 67 17 33 0 83 40.00
5 33 Danny 0 0 0 8.25
7 0 0 0 0 50 10.00
5/ Moist after 3 Days 17 Danny 33 50 17 29.25
7/ Moist after 3 Days 0 67 17 17 50 30.20
7/ Moist after 5 Days 33 Danny 0 0 17 12.50
Table 8. Percent emergence of sea oat rhizomes uprooted,
immersed in sea water, and planted after 3, 5, 7, 9, and 11 days
exposure and placed in wet burlap after 3 days and planted 9
and 11 days after uprooting and either planted in an unwatered
or watered section on the beach of Santa Rosa Island, Florida in
Days of Exposure n Watered Unwatered
91 Wet Burlap
Treatment after 3
11/ Wet Burlap
Treatment after 3
Table 9. Percent emergence of sea oat rhizomes uprooted by
storm surge from Hurricane Georges (September 1998) which
were either collected 3 days after the surge, wrapped in wet
burlap and planted 2 days later or were collected and planted 5
days after uprooting. Rhizomes were planted in either a watered
or unwatered section of the beach on Santa Rosa Island,
Planted 5 Days After
Storm Surge n Watered Unwatered
Treatment 25 40 48
Moist After 3 Days 25 32 40
Although rainfall was generally average (June through October) in 1996 (Fig. 9),
rhizome survival was poor compared to other years. These rhizomes had most of their
top growth removed in October of 1995 by hurricane Opal and were recovering from
conditions associated with the tidal surge. Thus, the rhizomes excavated in 1996 may
have been of poorer quality (depleted in carbohydrate reserves) compared to those used
in 1997 and 1998. For those plants planted on the beach without water, differences in
survival among months may be related to rainfall as well. Low rainfall in September
and October of 1997 resulted in mean survival of 11% (lowest for all months) from
September excavated rhizomes while tillers associated with October excavated
rhizomes did not appear until March of 1998. High rainfall after rhizome planting in
1998 appeared to increase rhizome survival.
Most rhizomes uprooted by hurricane Georges were moist when found, even
though rhizomes were collected from sites such as along roads, on fences and at the
edge of wet depressions. In addition, the ground was saturated by precipitation
associated with the storm. Both conditions appeared to have contributed to the
increased survival of these rhizomes. Perhaps, the harsh treatment of rhizomes by the
research techniques employed was greater than those imposed by hurricanes. While no
one has attempted to utilize sea oat rhizomes uprooted by storm surge for restoration,
Dahl (1975) used divisions of established sea oat plants culmss attached to rhizome
segments) for restoration. Survival of these transplants (harvested in Oct April) was
0-47%. Based on 70 experimental beach plantings of sea oats, Dahl (1975) rated 50%
or better survival as excellent, 25-50% survival as very good. Using this rating system
a) I CO
0> 0), 0>
0> > 0
(oo) uo!0 o I
(wo) uoioe;!dpeJd 181o0
C .?; r~-~
re LL 0
the utilization of hurricane uprooted rhizomes is recommended as a restoration
technique, particularly if rhizomes can be collected and replanted quickly and watered.
In addition, planting sea oats and bitter panicum transplants without water also resulted
in good to excellent results.
Percent rooting. The initial analysis indicated only the main effect of propagation
substrate was significant and there were no significant interactions between the main
effects of propagation substrate, sex and auxin treatment. The propagation substrate did
have an effect on the percentage of cuttings that rooted (p= 0.0001) with cuttings
propagated in perlite:vermiculite rooting at 97.8% and cuttings propagated in
pinebark:sand rooting at 85.4%. The coarse texture of the pinebark:sand may have a
particle size too great for the fine textured roots of rosemary. The pinebark:sand also
retained a greater quantity of water than did the perlite:vermiculite. In addition, the
texture and water holding capacity of the perlite:vermiculite more closely resembles the
fine textured sand found in the native habitat of rosemary.
Root number. The initial analysis indicated the main effects of substrate (p= 0.0001),
auxin (p= 0.0001), and sex (p= 0.007) were significant. A substrate by auxin
interaction (p= 0.01) was also present; therefore, results for each substrate are
presented independently. Cuttings propagated in the perlite:vermiculite substrate
produced a mean of 13.1 roots per cutting while cuttings propagated in the
pinebark:sand substrate produced a mean of 7.04 roots per cutting. Cuttings from male
plants produced more roots than cuttings from female plants with males producing
10.68 and females 9.71 roots. Auxin application also influenced root numbers but the
response to auxin differed with the propagation substrate (Table 10). The greatest
number of roots per cutting for cuttings propagated in the perlite:vermiculite substrate
were achieved with NAA at 1,000 or 5,000 ppm and the Dip'N Grow (1:5) which
contained NAA at a concentration of 833.33 ppm. While NAA treatments appeared to
increase the number of roots per cutting compared to the control, root number did not
improve with liquid formulations of IBA. In addition, the higher concentration of IBA
may have reduced root number. For cuttings propagated in the pinebark:sand substrate
the number of roots per cutting was lower than for cuttings propagated in the
perlite:vermiculite substrate. The greatest number of roots for cuttings propagated in
the pinebark:sand substrate occurred with Dip'N Grow (1:20) with 9.06 roots per
cutting; the lowest value among cuttings propagated in the perlite:vermiculite substrate
was 9.40 roots per cutting. Liquid formulations of IBA at 1,000 and 5,000 ppm
resulted in the fewest roots per cutting. Among cuttings propagated in the
pinebark:sand substrate, no auxin treatment resulted in a greater root number than the
Root length. The initial analysis indicated the main effects of substrate (p= 0.002) and
sex (p= 0.04) were significant. Substrate by auxin (p= 0.0001) and substrate by sex
(p= 0.009) interactions were also present; therefore, results for each substrate are
presented independently. Cuttings propagated in the perlite:vermiculite substrate
produced roots with a mean length of 2.35 cm (0.94 in) while cuttings propagated in
the pinebark:sand substrate produced roots with a mean length of 2.82 cm (1.13 in).
Root length of cuttings from male and female plants differed only for the cuttings
propagated in the perlite:vermiculite substrate with root length of female cuttings an
Table 10. Influence of auxin treatment on root number and root length of Ceratiola ericoides
(Rosemary) rooted in two propagation substrates. Means within a column followed by the same
letter do not differ (LSD alpha = 0.05).
Auxin treatment Perlite:vermiculite Pinebark:sand
Root number Root length Root number Root length
Hormodin 1 12.31 cde 1.85 de 8.88 ab 3.69 a
Hormodin 3 12.96 bcde 1.89 de 6.65 bc 3.19 abc
Dip'N Grow (1:20) 13.57 bed 2.60 be 9.06 a 3.20 ab
Dip'N Grow (1:10) 14.33 b 2.91 ab 7.38 abc 2.89 abc
Dip'N Grow (1:5) 16.25 a 3.45 a 7.98 abc 2.38 bc
NAA 1,000 ppm 14.21 be 2.41 bcd 6.64 be 2.33 bc
NAA 5,000 ppm 14.78 ab 2.82 ab 6.26 be 2.22 c
IBA 1,000 ppm 11.25 e 1.59 e 5.57 bc 3.10 abc
IBA 5,000 ppm 9.40 f 2.11 cde 5.26 c 2.70 abc
Nontreated control 11.92 de 1.86 de 7.00 abc 2.55 abc
LSD alpha = 0.05 1.90 0.63 3.73 1.21
average of 2.04 cm (0.82 in) and root length of male cuttings and average of 2.67 cm
(1.07 in). Mean root length for cuttings propagated in the pinebark:sand substrate was
2.82 cm (1.13 in). Auxin application also influenced root length but the response to
auxin differed with the propagation medium (Table 10). For cuttings propagated in the
perlite:vermiculite substrate, root length was increased over that of the nontreated
control with the application of auxins containing NAA. The greatest root length for
cuttings propagated in the perlite:vermiculite substrate was achieved with all three
concentrations of Dip'N Grow and NAA at 1,000 ppm. Root length of cuttings
receiving auxin treatments containing IBA alone did not differ from the control.
Treatment with IBA would therefore not offer any benefit over nontreated cuttings. For
cuttings propagated in the pinebark:sand substrate the root length did not differ from
that of the control. Root lengths were equal to, or greater than, those of cuttings rooted
in the perlite:vermiculite substrate. This response was not unexpected since the cuttings
propagated in the pinebark:sand substrate also had fewer roots per cutting which would
allow for more carbohydrates to be allocated to root length.
Significance to Industry: These data demonstrate that rosemary can be successfully
propagated from softwood cuttings using a perlite:vermiculite substrate. Nurserymen
should expect lower rooting percentages and lower root numbers per cutting when
using a pinebark:sand substrate. Nurserymen can also expect to see slight differences in
root system quality among cuttings from male and female plants. In addition,
nurserymen can achieve an improvement of root quality by increasing root number and
root length with the application of a synthetic auxin containing 1,000 to 5,000 ppm
There were no interactions between the main effects of liner type and
production substrate. Production substrate had no effect on survival (73%) or shoot
number (12) but did influence plant height. Liners grown in pinebark:sand were
slightly shorter than liners grown in pinebark:peat:sand with heights of 41.1 cm and
43.4 cm, respectively. Slight differences in shoot number were evident among the
liner types with female and male cuttings rooted in perlite:vermiculite having 15 and 12
branches per cutting and female and male cuttings rooted in pinebark:sand having 11
and 10 branches per cutting, respectively. Although the total number of shoots differed
slightly among the four liner types the percentage of new shoots did not differ and the
percent increase in shoot number ranged between 24 and 34% for the four liner types.
Both production substrates are considered suitable for rosemary production.
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