Herbaceous Ornamental Field Trials

Introduction

Knox County Extension Master Gardener Volunteers have evaluated annuals at the Knox County Extension office site in Mt. Vernon, Ohio since 2006.  The field trial plots are planted, evaluated and maintained by volunteers. Approximately 6 volunteers work on this project, preparing the soil, planting starts in mid to late May, weeding it weekly and supplying moisture if natural rainfall is insufficient to meet the plants’ needs.

The soils in the plots are predominantly clay with a pH of 6.7, which are typical in central Ohio. The current plots were established in the spring of 2006. The beds were tilled to a depth of 12" and 2" of composted manure was added and 1” of compost was added again in 2007. There is approximately 480 square feet of bed space in full sun with an additional 480 square feet being prepared for the 2008 growing season.

The Clark County Master Gardener Volunteers have sourced the plants to Knox County and the selection of plants varies from year to year based on plot size and availability of plants.  The selection is also based on entries from seed companies, performance in prior years, on current trends, and on industry recommendations. In this section, the results of performance for the plants are based on the data collected at the plots. The data reflects the growing conditions of 2007. The purpose of the evaluation is to provide growers, landscapers, and homeowners a guide for plant selection for Ohio.

Method

The plants for 2007 were picked up at the Gateway Learning Gardens on May 30^th (http://clark.osu.edu/hort/fieldtrials06.htm) and planted on May 31^st.  Rows were spaced 18” apart and 12” between plants.  Trailing or vining plants were spaced 2' apart in the row with 4' between rows.

Country Colors Greenhouse of Mt. Vernon supplied several varieties for the plots this summer including: hibiscus, osteospermum, vinca, and zinnia.  They also supplied Posey Power Compost that was used in two smaller beds that had failed to produce plants the previous season.  The compost worked quite well, with each bed producing a spectacular display of flowers.

Osmocote™ (19-6-12) fertilizer was incorporated into the soil prior to planting at the labeled rate. No additional applications of fertilizer were made. Irrigation was applied during dry periods so that plants received at least 1" of water per week.  No mulch was used.  Hand weeding was completed as needed.  Plants were grown in full sun.  No insecticides or fungicides were applied. The plants were not deadheaded or pruned during the growing season.

Three people conducted visual evaluations in June, August, and September. The entire row was given a visual rating from 1 to 5. If there were less than 2 plants remaining in one row at any time during the evaluation, the variety was dropped from the trials and the result is listed as “dead.” A rating of 5 was considered to be excellent and a rating of 1 was considered to be poor. The 3 individual evaluation ratings were averaged for the monthly rating figure. The monthly evaluations (June-September) were averaged for the overall rating for each variety.

Weather Information

Precipitation at planting time in May was slightly below normal and temperatures were normal. The annuals were planted under good soil conditions and plants were irrigated in the first weeks in order to establish a good root system.  Above normal temperatures in June through September also meant that soil moisture levels were below normal averages. 

Evaluation and Ranking

Master Gardener Volunteers evaluated each variety 2-3 times throughout the summer for quality and desirability of foliage and blooms.  A scale of 1 to 5 was used with 1 being the lowest and least desirable and 5 being the highest and most desirable.  Following are the varieties in the 2007 field trials and their monthly ratings and overall rating. They are listed in alphabetical order.

List of Varieties in Trials

A-C          D-O          P-S          V-Z

Sources:

BFP- Ball Flora Plant (ballfloraplant.com)

FSH- Fischer (fischerusa.com)

PAS- Pan American Seed® (panamseed.com)

PW- Proven Winners® (provenwinners.com)