surges may inundate backshore plantings, but usually do not erode or deposit much 

 sediment, since most wave energy is dissipated near the berm. Often, the result is a gradual 

 flooding of the planting rather than wave attack. However, lower elevation hurricane 

 washover channels may suffer erosion or sediment deposition. 



Survival and growth, expressed as the relative number of plants with visible nonchlorotic 

 green leaves or new shoots, was determined at approximately weekly intervals for both open 

 and protected beach monthly plantings on north Padre in 1973-74. Data were collected 

 until no further changes occurred or individual plants could no longer be distinguished. 

 Survival data for representative months, and periods of saltwater inundation, are shown in 

 Figures 28 and 29; comparisons include open versus protected beach, two categories of 

 panicum culms, and season of planting. The latter two comparisons will be discussed later. 



In these figures, the effect of inundations is unclear. October sea oats (Fig. 28) had a 

 gradual decline in survival after an early inundation. The same surge on the November 

 planting may account for much of the difference between this and the protected planting 

 survival. Inundation several months after planting appears to have had little influence. Bitter 

 panicum tillers planted in October and November (Fig. 29) exhibited a gradual decline in 

 survival after inundations, but a similar decline in the December planting occurred a month 

 before the surge. The three panicum primary culm plantings did not respond negatively to 

 the inundations. These inundations were not accompanied nor followed by rain for over 

 2 weeks. 



The effects of inundations have been variable, ranging from total failure of some past 

 plantings to little response. One major plot in the north (1,200-foot dune-width panicum), 

 inundated by a surge soon after planting, had over 70 percent survival and is one of the most 

 successful dunes for rapid growth and maximum accumulation of sand. 



In summary, inundation of a planting by a minor surge, lasting 1 to 2 days, is not always 

 detrimental, but can affect survival if it occurs during a drought, especially if the water 

 remains ponded on the planting for several days. 



/. Season of Planting. Transplant survival, as determined from monthly test plantings, is 

 influenced more by soil salinity, soil moisture and TAC, than by seasonality. Tests to 

 determine the best time of planting were conducted monthly from 1970 to 1972, fall 

 through spring. Data from Table 16 show that sea oats had an optimum planting season 

 from December through March. December was the best month on south Padre, wliile 

 January was best in the north part. Unlike sea oats, the best planting time for bitter 

 panicum was not limited to a short season, but could be transplanted from November 

 through May with good results if soil moisture was high. 



In 1973, test plantings were continued year round on both north and south Padre. 

 Atypically high precipitation from June through October on north Padre may have been 

 unusually advantageous to the plants, but in the south, rainfall was near normal. Data 

 (Table 16) show that either species can be planted year round; but bitter panicum survival 



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