Promoting Root Development on Bearded Iris

Transcription

1 Promoting Root Development on Bearded Iris In many instances, bearded iris do not develop roots after planting. This may be a stress induced dormancy. Objectives Overcome this stress or dormancy using different forms of Gibberellic Acid or KleenGrow. Promote root development and top growth.

2 Methods The individual plants were evaluated and separated into two groups prior to making the treatments. Rhizomes with a small amount of rooting (left) Rhizomes with no roots present (right) At 13 and 60 days following the applications, only the rhizomes which had no roots initially were evaluated.

3 The Treatments ProGibb (GA3) 500 ppm 10-minute Dip ProGibb (GA3) 500 ppm Drench NovaGib (GA4+7) 500 ppm 10-minute Dip NovaGib (GA4+7) 500 ppm Drench ProGibb 250 ppm + NovaGib 250 ppm Drench KleenGrow 13 oz/100 gals 10-minute Dip KleenGrow 13 oz/100 gals Drench Untreated (Water Drench)

4 Preliminary Results Untreated/Water Drench 13 Days After Application

5 Preliminary Results NovaGib (GA4+7) 500 ppm Drench 13 Days After Application

6 Preliminary Results NovaGib (GA4+7) 500 ppm Dip 13 Days After Application

7 Preliminary Results ProGibb (GA3) 250 ppm + NovaGib (GA4+7) 250 ppm Drench 13 Days After Application

8 Preliminary Results KleenGrow 13oz/100gals Drench 13 Days After Application

9 Preliminary Results 13 Days After Application Treatment Rankings Best to Least 1ProGibb (GA3) Drench - Moderate Rooting Best Top Growth 2KleenGrow (13oz/100gals) Drench Moderate Rooting 3ProGibb (GA3) + NovaGib (GA4+7) Drench Moderate Rooting 4NovaGib (GA4+7) Dip Slight to Moderate Rooting on Most 5NovaGib (GA4+7) Drench Slight Rooting on Most 6Untreated (Water Drench) No to Slight Rooting 7ProGibb (GA3) Dip No to Little Injury Possible Injury 8KleenGrow (13 oz/100 gals) Dip No to Slight Rooting Possible Injury

10 Preliminary Results ProGibb 500 ppm Dip 13 Days After Application

11 Preliminary Results ProGibb (GA3) 500 ppm Drench 13 Days After Application

12 Final Evaluation Only the results of the plants which had NO roots present when the applications were made are displayed in this document. These plants were evaluated using the tug test to determine the degree of rooting. They were assigned an establishment rating based on the results of the tug test using the scale displayed on the right. 0 = No roots present Rhizomes lifted easily 1 = Very lightly rooted Rhizomes lifted slightly, but were lightly anchored 2 = Moderately rooted Rhizomes firmly anchored, little movement when lifted. 3 = Heavily rooted Rhizomes firmly anchored, no movement when lifted.

13 Final Results ProGibb Dip 54.55% No Roots 45.45% With Roots Establishment Rating = 0.546* * Rating based on all plants which did not have roots present at the time of application. Untreated Top ProGibb 500 ppm Dip 10 Minutes 60 Days After Application

14 Final Results ProGibb Drench 50% No Roots 50% With Roots Establishment Rating = 1.0* * Rating based on all plants which did not have roots present at the time of application. Untreated Top ProGibb 500 ppm Drench 60 Days After Application

15 Final Results NovaGib Dip 37.5% No Roots 62.5% With Roots Establishment Rating = 0.875* * Rating based on all plants which did not have roots present at the time of application. Untreated Top NovaGib 500 ppm Dip 10 Minutes 60 Days After Application

16 Final Results NovaGib Drench 60% No Roots 40% With Roots Establishment Rating = 0.4* * Rating based on all plants which did not have roots present at the time of application. Untreated Top NovaGib 500 ppm Drench 60 Days After Application

17 Final Results ProGibb + NovaGib Drench 38.46% No Roots 61.54% With Roots Establishment Rating = 0.923* * Rating based on all plants which did not have roots present at the time of application. Untreated Top ProGibb 250 ppm + NovaGib 250 ppm Drench 60 Days After Application

18 Final Results KleenGrow Dip 92.86% No Roots 7.14% With Roots Establishment Rating = 0.143* * Rating based on all plants which did not have roots present at the time of application. Untreated Top KleenGrow Dip 60 Days After Application

19 Final Results KleenGrow Drench 30% No Roots 70% With Roots Establishment Rating = 1.5* * Rating based on all plants which did not have roots present at the time of application. Untreated Top KleenGrow Drench 60 Days After Application

20 Summary ProGibb 250 ppm % Developed Roots + NovaGib 250 ppm Drench 61.54% ProGibb 500 ppm Dip 45.45% ProGibb 500 ppm Drench 50% 1.0 NovaGib 500 ppm Dip 62.5% NovaGib 500 ppm Drench 40% 0.4 KleenGrow Dip 7.14% KleenGrow Drench 70% 1.5 Establishment Rating Untreated (Water) 20% The above results were only determined on the rhizomes which did not have any roots present at the time the applications were made.

21 Final Results 60 Days After Application Treatment Rankings Best to Least (Based on Rooting) 1KleenGrow (13oz/100gals) Drench 2ProGibb (GA3) + NovaGib (GA4+7) Drench 3ProGibb (GA3) Drench - Moderate Rooting 4NovaGib (GA4+7) Dip 5ProGibb (GA3) Dip 6NovaGib (GA4+7) Drench 7Untreated (Water Drench) 8KleenGrow (13 oz/100 gals) Dip

22 Final Results All treatments containing Gibberellic Acid (GA3 or GA4+7) resulted in considerably more iris rhizomes with roots present compared to the untreated rhizomes. KleenGrow applied as a drench was the most effective treatment overall. Interestingly, KleenGrow as a dip was the least effective treatment and actually had fewer roots than the untreated plants. In most instances, drenches were generally more effective than Dips. Both GA and KleenGrow may be effective options to promote rooting on bearded iris which do not develop roots after planting.

23 Final Results The response was fairly quick. Within 13 days of the applications, the rhizomes went from having no roots to developing roots which were several inches in length in some instances. Drenches would most likely be the growers preferred application method. The rate of Gibberellic Acid may be able to be reduced from the rates tested. The KleenGrow drench application would be more cost effective than the Gibberellic Acid drenches.

24 Recommendations General Apply KleenGrow (13 oz/100 gals) drench after planting. Make a second drench application following the first. This program is intended to be applied to ALL iris regardless of their health. This application will serve as a preventative bactericide/fungicide application for soft rot of the rhizomes as well as for promoting root development. When Poor and/or Delayed Rooting Occurs- If the bearded iris do not develop roots within two weeks after planting, apply KleenGrow (13 oz/100 gals) drench. One application may be sufficient. Apply again after 14 days if a reasonable number of plants have not developed roots. These recommendations are based on the preliminary results of this one trial and may change as we learn more about why no rooting occurs on bearded iris and how to overcome these situations.

25 Additional Observations Trim Height At Harvest There appears to be a correlation between the height the plants are trimmed and their ability to root. Plants with which are trimmed very short close to the rhizome appear to root more poorly than those that are cut higher. This is more evident on small rhizomes.

26 Additional Observations Trim Height At Harvest The poor rooting related to the trim height may be able to be resolved by storing them for a period of time prior to planting. This allows the rhizomes to dry, cure and overcome the stress they have undergone during harvesting, processing and shipping. This was observed on this group of iris which was small. It was held in a building for 10 days before shipping and planting. All of them rooted.

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