
Effect of ROOTBLAST®, or no fertilizer on Growth and Flowering
of Viola xwittrockiana and Pelargonium xhortorum cultivars.
Laura Deeter, PhD.
Dr. Deeter received her PhD from The Ohio State University in
2002. Her dissertation was on road salt tolerance of 38 species
of herbaceous perennials, under the direction of Dr. Steven Still.
Her areas of interest include salt tolerance of herbaceous plants,
stress tolerance in landscape plants, and installation and planting
practices relating to performance of ornamental plants in the
constructed landscape. She teaches woody and herbaceous plant
identification, perennial production and landscape maintenance
at Ohio State ATI.
Assistant Professor – Horticulture
Technologies
Ohio State University Agricultural Technical Institute
INTRODUCTION
Rootblast® is a granular, slow release fertilizer designed
for the homeowner and gardener (http://www.rootblast.cc/default.asp).
The effects of fertilizer on plant growth are well documented.
Plants acquire their nutrients for growth and development from
the soil through the root system. A healthy root system is thus
required for overall healthy development (Marschner, 1996). “The
ability of plants to absorb both water and mineral nutrients from
the soil is related to their capacity to develop an extensive
root system” (Taiz and Zeiger, 1991). Although there are
questions as to exactly which part of the root is most actively
involved in nutrient uptake (Bar-Yosef, et al., 1972 and Greenwood
et al., 1974) there is little disagreement that a full, healthy
root system is required for proper growth and development of plants.
The chemical Rootblast® was developed with the idea of developing
a full root system that could be easily utilized by the homeowner
on a wide range of plants. The product is a small amount of macronutrients
(2-1-2, N-P-K) and a mix of micronutrients that is designed to
be utilized in all stages of growth and development from seedlings
to established plants. This research was designed to look at growth
and flowering of two species of common bedding plants (Viola xwittrockiana
and Pelargonium xhortorum) in response to the product Rootblast®.
MATERIALS AND METHODS
Soil was gathered from the woods north of the The Ohio State University
Agricultural Technical Institute in Wooster, OH. The soil was analyzed
and found to have 14% organic content, 35% clay, 40% silt and 25%
sand, classifying this as a clay-loam soil. The pH of the sample
was 5.8. Twenty four 6 _” pots were filled with this soil
and 1 tsp of Rootblast was mixed into each pot. Sixteen Viola and
eight Pelargonium were transplanted into the pots on August 8, 2005.
Half of each species were the control plants, the other half would
receive the treatment.
The Pelargonium were each pruned to a similar height, and had all
old flowers and faded foliage removed to represent proper planting
procedures for this time of the growing season in Ohio. The Viola
were recent transplants when purchased and needed no pruning. Plants
were placed into the greenhouse and watered as needed with distilled
water for 6 weeks. Plant height was recorded at the beginning of
the experiment. Time to flowering was noted during the six weeks,
and final plant height was recorded along with overall appearance.
RESULTS
The Pelargonium were actively growing at purchase, and many had
flowers, although it was obvious from their general appearance that
the beginning of August is not the best time for purchasing new
plants. The Viola were shipped as newly seeded plants in a 32-cell
plug tray. Their starting appearance was as expected for new seedlings,
full, healthy and dark green, though none were in flower.
Pelargonium treated with Rootblast flowered earlier and had greater
numbers of flowers compared to untreated plants. The treated plants
branched more, and had greater numbers of leaves, which were larger
and greener than untreated plants. The treated Pelargonium were
also slightly taller, than untreated plants. The root systems, although
not fully developed after six weeks, were significantly greater
than untreated plants.
Viola, however, showed significantly greater numbers of flowers
earlier than untreated plants, and had much bigger foliage in larger
numbers which was darker green compared to the untreated counterparts.
Although the height for the treated vs. untreated plants is not
greatly different, Viola is a plant that does not get very tall
during the growing season, thus a limited height difference is perhaps
to be expected. Table 1 shows the beginning and ending heights for
all plants. Table 2 shows the effect of Rootblast® on the flowering
of Pelargonium and Viola. Figures 1 through 4 show photographs of
treated plants vs. untreated plants.
Table 1. Effect of Rootblast® on height
of Pelargonium xhortorum and Viola xwittrockiana cultivars during
six weeks of growth. Pelarg TB = Pelargonium treated, beginning,
Pelarg TE = Pelargonium treated, ending, Pelarg UB = Pelargonium
untreated beginning, Pelarg UE = Pelargonium untreated ending. Viola
TB = Viola treated beginning, Viola TE = Viola treated ending, Viola
UB = Viola untreated beginning, Viola UE = Viola untreated ending.
All heights are in inches; avg = average height for all replications
for that treatment, Std. Dev = standard deviation for all replications
for that treatment.
| |
Pelar
gTB |
Pelarg
TE |
Pelarg
UB |
Pelarg
UE |
Viola
TB |
Viola
TE |
Viola
UB |
Viola
UE |
| |
2 |
6 |
2 |
6 |
1 |
3 |
1 |
3.5 |
| |
3 |
8 |
2 |
6 |
1.5 |
3.5 |
1 |
4 |
| |
4 |
8 |
3 |
6.5 |
1 |
4 |
1.5 |
4.5 |
| |
3 |
7.5 |
3 |
5.5 |
1.5 |
4 |
1.5 |
3.5 |
| |
|
|
|
|
1 |
3.5 |
1 |
3.5 |
| |
|
|
|
|
1 |
4 |
1 |
3 |
| |
|
|
|
|
1.5 |
4 |
1 |
3.5 |
| |
|
|
|
|
1 |
3 |
1 |
4 |
| Avg. |
3 |
7.3 |
2.5 |
6 |
1.2 |
3.7 |
1.1 |
3.7 |
Std.
Dev. |
0.8 |
0.9 |
0.6 |
0.4 |
0.3 |
0.5 |
0.2 |
0.5 |
Table 2. Effect of Rootblast® on flowering
of Pelargonium xhortorum and Viola xwittrockiana cultivars during
six weeks of growth. Pel TBF = Pelargonium treated beginning flowers,
Pel TEF = Pelargonium treated ending flowers, Pel UBF = Pelargonium
untreated beginning flowers, Pel UEF = Pelargonium untreated ending
flowers. Viola TBF = Viola treated beginning flowers, Viola TEF
= Viola treated ending flowers, Viola UBF = Viola untreated beginning
flowers, Viola UEF = Viola untreated ending flowers. Avg = average
number of flowers for all replications for that treatment, Std.
Dev = standard deviation for all replications for that treatment.
| |
Pelarg
TBF |
Pelarg
TEF |
Pelarg
UBF |
Pelarg
UEF |
Viola
TBF |
Viola
TEF |
Viola
UBF |
Viola
UEF |
| |
0 |
3 |
0 |
1 |
0 |
6 |
0 |
1 |
|
0 |
4 |
0 |
2 |
0 |
5 |
0 |
0 |
|
0 |
3 |
0 |
2 |
0 |
7 |
0 |
0 |
|
0 |
4 |
0 |
0 |
0 |
8 |
0 |
2 |
|
|
|
|
|
0 |
4 |
0 |
3 |
|
|
|
|
|
0 |
5 |
0 |
2 |
|
|
|
|
|
0 |
8 |
0 |
1 |
|
|
|
|
|
0 |
3 |
0 |
2 |
|
|
|
|
|
|
|
|
|
Avg |
0 |
3.5 |
0 |
1.25 |
0 |
5.75 |
0 |
1.375 |
Std.
Dev |
0 |
0.57735 |
0 |
0.957427 |
0 |
1.832251 |
0 |
1.0606602 |
Figure 1. Pelargonium treated with Rootblast® (on the left)
vs. Pelargonium left untreated (on the right). Both plants were
pruned to the same size at the start of treatment and left to grow
for 6 weeks.
Figure 2. Viola treated with Rootblast®
(on the left) vs. Viola left untreated (on the right). Both plants
were grown for 6 weeks.
Figure 3. Root mass of Viola xwittrockiana
treated (top) and untreated (bottom) with Rootblast® and left
to grow for six weeks in 6 _” containers with a clay-loam
soil.
Figure 4. Roots of Pelargonium xhortorum
treated (left) and untreated (right) with Rootblast® and left
to grow for six weeks in 6 _” containers with a clay-loam
soil.
DISCUSSION and CONCLUSION
Pelargonium and Viola treated properly with Rootblast® showed
greater numbers of flowers and increased growth over plants that
were untreated. Although the height difference for Viola is limited,
Viola is a plant whose mature height is in the 4-6” range,
thus a large height difference would not be expected. The height
difference for Pelargonium was much greater, expected for a plant
whose final height could be in the 12-18” range at the end
of a full growing season. These plants were grown for only 6 weeks,
thus were not given a full growing season to develop fully.
The root systems of treated vs. untreated plants are dramatically
different. Plants treated with Rootblast® developed significantly
larger root systems during the six weeks of this experiment. The
larger root systems would lead to larger plants, earlier flowering,
increased numbers of leaves and better plant establishment in the
landscape. Although it was difficult to see the numbers of roots
on untreated Pelargonium, the roots of the treated plants were larger
and readily visible. However, the root mass on Viola showed dramatic
differences between treated and untreated plants. Treated plants
had a root mass, that although didn’t fill the container,
was 2-3 times larger than untreated plants. Given a longer testing
period, that different might be even greater.
The numbers of flowers produced by the treated plants would support
a more developed root system in treated plants. The flowers were
larger and in greater numbers for the Pelargonium and in dramatically
increased numbers for Viola. Both species flowered approximately
one week earlier than untreated plants.
If the Pelargonium were treated at the beginning of the season,
rather than at the end of the season, it is possible the results
would have been more dramatic as the plants may have been more actively
photosynthesizing and growing. Viola is a cool season plant that
growers are often starting toward the “end” of the growing
season for fall sales and planting. Thus it is not surprising to
find dramatic changes between fertilized and unfertilized plants.
The effects of Rootblast® are such that these two species grew
taller, flowered more and earlier, and appeared to be healthier
to observers.
Rootblast® is effective in providing plants the initial nutrients
required to develop a healthy root system in NE Ohio soils. Adding
Rootblast® to newly planted bedding plants should allow the
plants to develop faster, flower earlier and fill in faster than
adding nothing to the soil at planting.
Works Cited
Bar-Yosef, B., U. Kafkafi, and E. Bresler. 1972. Uptake of phosphorus
by plants growing under field conditions. Soil Science. Vol. 36.
Greenwood, D., J. Wood and T. Cleaver. 1974. A dynamic model for
the effects of soil and weather conditions on nitrogen response.
Journal of Agricultural Science. Vol. 82.
Marschner, H. 1995. Mineral Nutrition of Higher Plants. Academic
Press. London.
Taiz, Lincoln, and E. Zeiger. 1991. Plant Physiology. Benjamin/Cummings
Publishing Co. Inc. Redwood City CA.
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