North Carolina

Flower Growers'

BulletinVolume 40, Number 6

December, 1995

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F • G • A

Official Publication of the North Carolina Commercial Flower Growers' Association

Garden Chrysanthemum Culture the Easy

WayRoy A. Larson and Ingram F. McCallDepartment of Horticultural Science

North Carolina State University, Raleigh

For the past several years we have beenwitnessing the experiences and theplants garden chrysanthemum growers

have had. Some growers were very successfuland scarcely need an article on garden mumculture. Some growers encountered difficulties,often because they didn't do something when itneeded doing, or they did it when itshouldn't have been done. Fortunatelygarden mums are somewhat "forgiving"plants and success is achieved thoughfailure is justified.

During the winter of 1995we decidedto work with garden chrysanthemums inthe spring, summer and fall. We wantedtocomparetwofertilizerratesandmanualpinching versus the use ofFlorel®. We hadheard some of the presentations PeterKonjoian, Andovers, Massachusetts, hadmade on the use of Florel and we had seenmany plants treated with the chemical.Florel seemed to overcome a real hurdleencountered by garden mum growers... Figure

the need for a second manual pinch... but mostgrowers we talked to seemed unaware of itsbenefits, and seemed cautious about anythingthat involves ethylene. Such misgivings areunderstandable, as the consequences of ethylenepollution in a greenhouse can be devastating(Figure 1). The controlled release of ethylene

1. Ethylene injury on a 'Shoesmith' culdvar.

N.C. Flower Growers' Bulletin - December, 1995

Figure 2. Florel-treated garden mum. Photo taken atC. Merkel and Son, Mentor, Ohio.

from a growth regulator such as Florel (Pistill)can be very helpful, however (Figure 2).

We wanted to make certain that we would use

cultivars which were popular so we asked foradvice from Ed Higgins, the chrysanthemumproject manager at Yoder Brothers, Inc.,Barberton, Ohio. We not only asked for advice,we asked for rooted cuttings, and Yoders sent usthe following: 'Bravo', 'Debonair', 'Jennifer','Jessica', 'Linda', 'Lynn', 'Megan', 'Raquel',Tolima' and 'Yellow Triumph'. We plantedthese cuttings on June 8, one per 8 inchcontainer, in Metro Mix 360. The potswere placed on 18" centers under a saranshade at the Horticultural Field Laboratory.Watering was achieved with a tubeconnected to a ring in each pot.

We had 100 plants ofeach cultivar, and50 received 300 ppm N once a week and theother 50 received 500 ppmN. The fertilizerused was 20-10-20. Osmocote® (14-14-14) was applied as a top dressing twoweeks after planting, at a rate of 2teaspoonfuls per pot. All of the plants ineach treatment were given the first pinchon June 26, which was 18days after plantingwhen root systems were well established.On July 14 half of the plants in each

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treatment were manually pinched again, whilethe other half were sprayed with Florel at 500ppm.

No insecticides or fungicides were used andthe major pest problems were rabbits. Theyseemed to have a preference for 'Debonair', butthat might have been because of the location ofthat cultivar, which was at one end of the plot. Achicken wire fence corrected that situation. No

growth regulators were used other than Florelwere used.

Results and Discussion

Plants treated with Florel were delayed in theappearanceof flowerbuds andearly developmentcompared to the manually pinched plants (Figure3), but the differences were not noticeable at theconclusion of the experiment. Plant size wassimilar for all plants of a given cultivar, and therewas very little difference among cultivars. Theplants were 16 to 19inches tall, measuring fromthe ground to the top of the plant. Flowers werenot counted but there seemed to be little difference

among treatments (Figure 4). We modestly ratedall of the plants as very good, and the plantIngram McCall is holding (Figure 5), was typicalof all of the plants in the experiment.

Figure 3. Florel (Left) versus manual pinch (Right). Plantswere feed with 300 ppm N. Slide take 25 September 1995..

N.C. Flower Growers' Bulletin - December, 1995

Figure 4. Although Florel delayed the onset offlower buds andearly development, there was no measurable difference in dateofflowering between the Florel and manual treatments.

Several applications of Florel have beensuggested, to keep the plants vegetative when thegrower wants them in that state, and toproduce a multitude of breaks. Ourplants would have suffered a loss ofquality if we had more shoots at the 18"spacing. One application seemed to bevery adequate. It also has been suggestedthat more than cutting be planted in eachcontainer, to enable a grower to plantlater and still have plants of the desiredsize and flower number. An early Juneplanting, a mid-June final pinch, andnatural daylengths resulted in a floweringperiod of late September and earlyOctober. The Men's Garden Club of

Wake County has a large garden mumproject for the N.C. State Fair FlowerShow, which is held in mid-October.

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They planted their cuttings the same weekwe planted ours, they put three cuttingsper pot, and they had to use B-Nine forheight control on the same cultivars wegrew. Locations of the two garden mumsites are about one mile apart.

There was no advantage in using 500ppm N, when plants given 300 ppm wereof a comparable size and exhibited nodeficiency symptoms. There was adefinite labor-saving advantage in usingFlorel.

We wish to acknowledge YoderBrothers, Inc. for the mum cuttings, Scottsfor the donation ofsubstrate and fertilizer,and Dr. Mike Benson, Department ofPlant Pathology, NCSU, for letting ususe his saran-covered space and his

irrigation system at the Horticultural FieldLaboratory.

Figure 5. Ingram McCall with a 'Bravo' chrysanthemum.

NCCfGf) Membership Reneosafs are due on JJanuary f996. Pfease Mail Yours in Todaui •