Acclimatization of Brassaia actinophylla
and Schefflera arboricola

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R.T. Poole and C.A. Conover*

University of Florida/IFAS
Central Florida Research and Education Center
CFREC-Apopka Research Report RH-93-8

Summary

Schefflera arboricola (dwarf Schefflera) grown under high light with 10 or 15 g of 19-6-12 Osmocote per 6-inch pot produced tall, good quality plants with sturdy stems that remained upright indoors. Best quality dwarf schefflera plants after eighty-six days indoors were grown in 7500 ft-c and plants maintained under interior light intensities of 75 or 150 ft-c were of comparable quality. Dwarf schefflera also maintained better quality than Brassaia actinophylla (schefflera) at 75 ft-c, making dwarf schefflera more suited for low light sites.

Introduction

The range of environments to which foliage plants can successfully adjust, and the time needed for adjustment, vary for individual species and also depend on previous growth conditions. Rapid adjustment to a wide range of environments, especially to low light interior conditions, is a desirable characteristic for foliage plants. In previous research, Schefflera arboricola (dwarf schefflera) performed better than Brassaia actinophylla (schefflera) when both were grown under similar light intensities and then placed in low light indoor conditions (75 ft-c).

High quality dwarf schefflera have sturdy stems and an upright growth habit. A problem sometimes associated with dwarf schefflera is weak stems that fall over (lodge) when plants are moved indoors. The following two experiments were conducted to determine the effects of production light levels and fertilizer rates on growth and quality of schefflera and dwarf schefflera maintained in low or medium interior light intensities.

Materials and Methods

Experiment 1 began on July 16, 1991 when liners of schefflera and dwarf schefflera growing in #72 cell-pack trays were potted into 6-inch containers, one cell per pot. Growing medium was composed of Florida sedge peat:pine bark:builder's sand (6:3:1, by volume) amended with 7 lbs/yd3 dolomite and 1 lb/yd3 Micromax (Grace/Sierra Co., Milpitas, CA 95035).

Schefflera and dwarf schefflera were grown to salable size in greenhouses where air temperatures ranged from 70 to 95°F and plants were watered three times per week. Maximum light intensity at plant level was 1500, 3000 or 6000 ft-c. Experiment 1 was a 3 x 3 x 2 factorial test, with 5 replications per treatment, using a single pot as an experimental unit. All containers were top-dressed with 5, 10 or 15 g/6-inch pot 19-6-12 Osmocote (Grace/Sierra Co., Milpitas, CA 95035) on July 16, 1991 and again on October 16, 1991.

When plants reached salable size (dwarf schefflera on October 10, 1991; schefflera on December 17, 1991), they were moved into interior environment rooms where light intensity from cool white fluorescent lamps was 75 or 150 ft-c for 12 hours daily. Air temperature in rooms ranged from 65 to 80°F. Watering schedules were changed to twice a week after plants were moved indoors.

Height, plant grade (based on a scale of 1 = dead, 2 = poor quality, unsalable, 3 = fair quality, salable, 4 = good quality and 5 = excellent quality) and number of lodged stems per plant were determined for dwarf schefflera on December 12, 1991. Height and plant grade were determined for schefflera on March 12, 1992.

Experiment 2, a 3 x 2 factorial with 5 replications per treatment, was initiated on April 9, 1992. Liners of schefflera and dwarf schefflera, in #72 cell-pack trays, were potted into 6-inch containers, one cell per pot, using the same potting mix as in experiment 1. Containers were top-dressed with 10 g/6-inch pot 19-6-12 Osmocote and moved to a greenhouse where light intensity at plant level was 2500, 5000 or 7500 ft-c. Air temperatures ranged from 70 to 95°F and plants were watered three times a week.

Schefflera in 7500 ft-c were damaged in May by heavy infestations of red spider mites and leafhoppers. Plants never regained full vigor and growth was slower compared to that expected for normal healthy plants. Height and plant grade measurements were adversely affected.

On July 21, 1992, when both schefflera and dwarf schefflera had grown to salable size, plants were moved into interior rooms. As in experiment 1, plants received 75 or 150 ft-c from cool white fluorescent lamps for 12 hours daily, air temperature ranged from 65 to 80°F and plants were watered two times per week.

Height and plant grade (based on same scale as in experiment 1) were recorded shortly after plants were moved indoors in July and again on October 20, 1992, when experiment 2 was terminated.

Results

In experiment 1, interaction of production light level and fertilizer rate affected schefflera quality (plant grade). Schefflera quality was better when plants received 3000 or 6000 ft-c light and 15 g/6-inch pot 19-6-12, but increases in fertilizer rate did not improve quality of plants produced under 1500 ft-c (Table 1).

Interaction of production light level and fertilizer rate in experiment 1 also affected number of lodged stems on dwarf schefflera Number of lodged stems after eighty-six days indoors increased for plants produced in 1500 ft-c (Table 2). Lodging was not a problem for plants grown under the two higher light intensities regardless of fertilizer rate because plants had sturdier stems that were better able to support foliage.

In both experiments, dwarf schefflera grown in the two higher light intensities were taller and had sturdier stems (when fertilized at the two higher rates) than plants in the low light (Tables 3 and 4). In comparison, production light level did not produce as much variation in height of the schefflera plants grown in experiment 1. Although schefflera produced in experiment 2 were shorter as light intensity increased, the extreme shortness of the crop grown under 7500 ft-c was probably due to combined stress of pests and light.

Plant grades of dwarf schefflera in both tests were much better when plants were grown in the two higher light intensities, 3000 or 6000 ft-c in experiment 1, 5000 or 7500 ft-c in experiment 2 (Tables 3 and 4). In experiment 1, schefflera grown in all three production light levels tested were of good quality. Schefflera quality in experiment 2 deteriorated as light intensity increased, but pest damage on plants under 7500 ft-c also reduced plant quality.

Only plant grade of schefflera in experiment 1 was affected by interior light intensities (data not shown). Schefflera in 150 ft-c received a 4.6 average plant grade compared to an average 3.8 for plants in 75 ft-c. Dwarf schefflera plant grades (average 4.1) were not influenced by interior light levels.

Conclusions

The highest production light intensities tested, 6000 ft-c in experiment 1, or 7500 ft-c in experiment 2, produced taller, sturdier dwarf schefflera with strong stems that remained upright when moved indoors. Furthermore, dwarf schefflera were able to adapt quickly without losing quality when moved from production light intensities as high as 7500 ft-c to low light interior conditions (75 ft-c).

Neither schefflera quality nor interior performance was enhanced by the higher production light levels and were best in both tests when plants were grown under the lowest production intensity and placed in an interior environment where light intensity was 150 ft-c.

These finding confirm earlier research which also showed dwarf schefflera was better able to maintain quality at low interior light intensities (75 ft-c) compared to schefflera. The most important finding of these two tests is the wider range of interior light levels to which dwarf schefflera can quickly adapt, when grown using production light levels high enough to promote sturdy stem growth. After time under 150 or 75 ft-c interior light intensities, best quality dwarf schefflera were those produced under the highest levels plants that are now commonly used in commercial nurseries for dwarf schefflera production (experiment 1) or higher (experiment 2).

*Professor of Plant Physiology and Professor of Environmental Horticulture and Center Director (retired 7/96), respectively, Central Florida Research and Education Center-Apopka. 2807 Binion Road, Apopka, FL 32703-8504.

References

  1. Braswell, J.H., T.M. Blessington and J.A. Price. 1982. Influence of cultural practices on postharvest interior performance of two species of schefflera. HortScience 17(3):345-347.
  2. Conover, C.A., A.R. Chase and L.S. Osborne. 1983. Brassaia and schefflera. Nurseryman's Digest 17(9):90-93.
  3. Conover, C.A., and R.T. Poole. 1990. Light and fertilizer recommendations for production of acclimatized potted foliage plants. Nursery Digest 24(10):34-36, 58-59.
  4. Conover, C.A., and R.T. Poole. 1979. Factors influencing acclimatization of Brassaia arboricola. Foliage Digest 2(10):5-6.
  5. Fonteno, W.C. and E.L. McWilliams. 1978. Light compensation points and acclimatization of four tropical foliage plants. J. Amer. Soc. Hort. Sci. 103(1):52-56.
  6. Pass, R.G. and D.E. Hartley. 1979. Net photosynthesis of three foliage plants under low irradiation levels. J. Amer. Soc. Hort. Sci. 104(6):745-748.
  7. Sarracino, J.M., R, Merritt and C.K. Cain. 1992. Light acclimatization potential of Leea coccinia and Leea rubra grown under low light flux. HortScience 27(5):404-406.

    Table 1. Effects of production light levels and fertilizer rates on plant gradez of Brassaia actinophylla (schefflera) after fifty-six days in an interior environmenty.

    Experiment 1. 19-6-12, g/6-inch potx
    Light intensity (ft-c) 5 10 15
    1500 4.1 4.2 4.1
    3000 4.0 4.2 4.5
    6000 3.8 4.2 4.5

    Interaction significant at P = 0.016. zPlants graded based on a scale of 1 = dead, 2 = poor quality, unsalable, 3 = fair quality, salable, 4 = good quality and 5 = excellent quality.
    yPlants grown in production light levels from July 16 until October 10, 1991 and maintained in interior environment rooms from October 10 until December 12, 1991.
    xFertilizer was applied July 16 and again October 16, 1991.

    Table 2. Effects of production light levels and fertilizer rates on number of lodged stems on Schefflera arboricola (dwarf schefflera) after eighty-six days in an interior environmentz.

    Experiment 1. 19-6-12, g/6-inch poty
    Light intensity (ft-c) 5 10 15
    1500 0.3 0.8 0.9
    3000 0.1 0.1 0.1
    6000 0.1 0.0 0.0

    Interaction significant at P = 0.006. zPlants grown in production light levels from July 16 until December 17, 1991 and maintained in interior environment rooms from December 17, 1991 until March 13, 1992.
    yFertilizer was applied July 16 and again October 16, 1991.

    Table 3. Influence of production light levels on height of Brassaia actinophylla (schefflera) after fifty-six daysz, and height and plant grade of Schefflera arboricola (dwarf schefflera) after eighty-six days in an interior environmenty. Experiment 1.

      Brassaia
    actinophylla    		 Schefflera
    arboricola    		 Schefflera
    arboricola
    Light intensity
    (ft-c)    		 Height
    (cm)    		 Height
    (cm)    		 Plant
    gradex
    1500 40 29 3.6
    3000 45 38 4.5
    6000 43 35 4.5
    Significancew      
    linear ns ** **
    quadratic ** ** **

    zPlants grown in production light levels from July 16 until October 10, 1991 and maintained in interior environment rooms from October 10 until December 12, 1991.
    yPlants grown in production light levels from July 16 until December 17, 1991, maintained in interior environment rooms from December 17, 1991 until March 13, 1992.
    xPlants graded based on a scale of 1 = dead, 2 = poor quality, unsalable, 3 = fair quality, salable, 4 = good quality and 5 = excellent quality.
    wns, **; Results nonsignificant or significant at P = 0.05, respectively.

    Table 4. Height and plant grade of Brassaia actinophylla (schefflera) and Schefflera arboricola (dwarf schefflera) after production compared to height and plant grade after time spent in an interior environmentz.

    Table 4a. Brassaia actinophylla
      Height
    (cm)    		 Height
    (cm)    		 Height
    change
    (cm)    		 Plant
    gradex    		 Plant
    gradex    		 Plant
    grade
    change
    Light intensity
    (ft-c)    		 Jul 27 Oct 20   Jul 23 Oct 20  
    2500 37.1 43.4 6.3 4.7 4.8 0.1
    5000 28.5 37.7 8.2 3.1 3.6 0.4
    7500 21.1 32.5 11.4 2.1 3.1 1.0
    Significancev            
    linear ** ** ns ** ** **
    quadratic ns ns ns ns ns ns
    Table 4b. Schefflera arboricola
      Height
    (cm)    		 Height
    (cm)    		 Height
    change
    (cm)    		 Plant
    gradex    		 Plant
    gradex    		 Plant
    grade
    change
    Light intensity
    (ft-c)    		 Jul 27 Oct 20   Jul 23 Oct 20  
    2500 17.3 20.5 3.2 2.0 2.8 0.8
    5000 27.1 28.7 1.6 3.3 4.4 1.0
    7500 23.3 26.9 3.6 3.7 4.6 0.9
    Significancev
    linear ** ** ns ** ** ns
    quadratic ** ns ns ns ns ns

    zPlant height (cm) and plant grade were determined for both species July 27, 1992, after greenhouse production, and again on October 20, 1992 after time spent in an interior environment.
    yHeight change = Plant height measured October 27 - plant height measured July 27, 1992.
    xPlants graded based on a scale of I = dead, 2 = poor quality, unsalable, 3 = fair quality, salable, 4 = good quality and 5 = excellent quality.
    wPlant grade change = plant grade determined October 20 - plant grade determined July 27, 1992.
    vns, **; Results nonsignificant or significant at P = 0.05, respectively.