Paclobutrazol Foliar Sprays to Suppress Growth on Landscape Shrubs

E. Thomas Smiley; Liza Holmes; Bruce R. Fraedrich

doi:10.48044/jauf.2009.045

Article Figures & Data

Figures

Tables

Download figure
Open in new tab
Download powerpoint
Figure 1.
Shearing to the initial uniform size to determine growth biomass using a PVC frame to define the initial plant size and shape.
Download figure
Open in new tab
Download powerpoint
Figure 2.
Residual from PBZ spray treatment shortly after applications were made. Left photo is of 1000 ppm application rate and right photo is with the 4000 ppm PBZ rate.
Download figure
Open in new tab
Download powerpoint
Figure 3.
Growth comparison of Abelia 18 weeks after treatment showing from left to right the nontreated control, 1000 ppm (low rate) PBZ (Cambistat) treated plant and the 4000 ppm (high rate) PBZ (Cambistat) treated plant.

Tables

Figures

View popup

Table 1.

Mean fresh weight biomass in Kg (Standard Error) of new growth measure 20 weeks after treatment by shearing shrubs to their pretreatment size and weighing the freshly cut leaves and twigs.

Species	Nontreated Control Kg (S.E.) of Biomass	1000 ppm PBZ Kg (S.E.) of Biomass	4000 ppm PBZ Kg (S.E.) of Biomass
Abelia × grandiflora	1.39 (.17) a^*	0.93 (.09) b	0.68 (.09) b
Ligustrum japonicum	4.13 (.35) a	3.13 (.17) b	2.62 (.12) b
Ligustrum sinense	1.07 (.14)	1.04 (.08)	0.93 (.14)
Loropetalum chinensis	2.16 (.08) a	1.54 (.08) b	1.46 (.08) b

↵^*Means followed by the same letter are not significantly different as determined by ANOVA test and Student-Newman-Keuls separation of mean, α = 0.05.

View popup

Table 2.

Mean new height and width growth which occurred, measured in cm at 3, 6, 12, and 18 weeks after shearing to a uniform size and treatment with PBZ spray.

Species	Height Growth in cm				Width Growth in cm
Species	Weeks after treatment	Control	1000 ppm PBZ	4000 ppm PBZ	Control	1000 ppm PBZ	4000 ppm PBZ
Abelia × grandiflora	3	15.8	10	9.4	18	13.4	12.9
	6	37.0 a^*	24.3 b	18.9 b	48.1 a	34.1 b	22.3 c
	12	37.2 a	31.8 ab	26.3 b	96.0 a	75.1 a	60.6 b
	18	41	39.6	33.4	102.9 a	82.5 ab	63.7 b
Ligustrum japonicum	3	4.2	1.7	1.3	6.2 a	6.0 a	3.5 b
	6	24.2 a	12.8 b	7.4 c	25.7 a	18.7 b	8.16 c
	12	70.8 a	56.9 b	31.9 c	70.9	66.6	61.14
	18	116.6a	107.9a	75.6 b	125.7	114.8	110.5
Ligustrum sinense	3	10.1	7.5	5.8	4.9	2.9	2.2
	6	19.4	15.2	15.1	16.9 a	13.1 a	7.3 b
	12	32.8 a	25.4 b	24.3 b	34.6	33.6	32.5
	18	56.6 a	38.1 b	31.6 b	67.3	62.6	61.5
Loropetalum chinensis	3	13.5	13.1	10.8	20.5	17.8	16.8
	6	28.7 a	19.2 b	18.0 b	35.7	29.9	28.6
	12	65.1 a	42.5 b	37.7 b	73	57.5	50.6
	18	83.5 a	66.1 b	51.8 c	121 a	102.9 b	91.6 b

↵^*Means followed by the same letter are not significantly different as determined by ANOVA test and Student-Newman-Keuls separation of mean, α = 0.05. Comparisons are within species, across the table, by week of measurement.