N.C. Flower Growers' Bulletin - June 2004 Volume 49, Number 3

Smoothing Out the Kinks of VegetativeAnnual Production

James L. "Jamie" Gibson, University of Florida-Milton andBrian E. Whipker, NC State University

Growers have faced drought, hot and cold weather,and excessive rainfall. Production problems withvegetative annuals are easier to handle. This articlehighlights production solutions from rooted cuttingestablishment to the retail bench. Grower-friendlyproduction resources are also provided.

Rooted Cutting InspectionWhenrootedcuttingsare receivedfromplantsuppliers,growers should always conduct a root and shootsurveyof the product (Table 1).These factorsare veryimportant to the success of cutting establishment.

Table 1. Cutting quality checklist.

Roots Shoots

Arc there plants with Are cuttings exhibitingyellow lower leaves or yellow lower or upperis the plant wilted which leaves indicating aindicates an infection of nutrient deficiency?a root rot pathogen?

Are the cuttings darkArc the cutting roots green, stunted, and withbrown or blackened crinkled leaves

which may indicate indicating that theexposure to high cuttings have beenfertilizer salts? treated with high doses

of plant growthAre there plants along regulators?the outside margin ofthe tray which are Are there any signs ofwilted or showing signs necrotic leaf spotsof dehydration, indicating fungalindicating the cuttings infection on the plugs?received wateringstress? Are the cuttings leggy?

Arc the plugs too old Arc there damagingwith root wrapping insects feeding on theobserved? foliage?

If quality problems with the plants are observed,growers must take immediate action with the plantsupplier. Waiting weeks or months to inform thesupplier of troubles opens up the issue of whendamage occurred and who is responsible. Growersshould invest in a digital camera so that photographscan immediately be sent to the supplier for proof ofdamage.

Rooted Cutting EstablishmentOne of the greatest cutting establishment challengesthat growers face is poor root development once traysare received. For example, shoots ofargyranthemum,heliotrope, and osteospermum may be perfectlyhealthy, while rooting is limited. Growers havechoices when it comes to improved cutting rooting.(1) Once rooted cuttings are received, the root substrateshould be allowed to dry slightly between irrigations.(2) Trays could be placed on heated rooting mats fora few days before transplanting to encourage betterrooting. (3) Rooted cuttings should be purchasedfrom propagators who utilize rooting hormones andmarket cuttings aftercomplete root ball development.(4) Cuttings could be purchased that are rooted infiber-wrapped plugs or polymer-type substrates. Thesesubstrates may provide the advantage ofallowing forearlier transplant than when loose mixes are used forrooting because the root ball remains intact even if thecutting is not very well rooted. (5) Unrooted cuttingscould be purchased and rooted on-site to meet theneeds of the business.

In addition, growers should always remove cuttingsfrom shipping boxes immediately upon receipt toprevent the negative effects of ethylene.

SchedulingMid to late-February is normally the critical time toplant vegetative annuals for spring sales. However,withsomeofthecoolerseason,frosttolerantvegetativeannuals like diascia, nemesia, osteospermum,snapdragon, and verbena, growers should begin toplant by mid to late-January to take advantage of the

N.C. Flower Growers' Bulletin - June 2004

Table 2. Suggested Planting Weeks forPopular Vegetative Annuals.*

Plant TypePot

Size

Plant

Week

Finish

Week

Cool season

Diascia

Nemesia

Osteospermum

4-inch 7-10 11-14

6-inch 5-8 11-14

HB 3-6 11-14

Intermediate

Petunia

Calibrachoa

Fuchsia

4-inch 9-12 13-16

6-inch 7-10 13-16

HB 5-8 13-16

Warm season

AngeloniaScaevola

Sweetpotalo

4-inch 11-14 15-18

6-inch 9-12 15-18

HB 7-10 15-18

* Includes 1 early week for production flexibility

early spring market. The basic production schedulefor most vegetative annuals is 4 to 6 weeks for 4-inchpots, 6 to 8 weeks for 6-inch pots and 8 to 10 weeksfor hanging baskets. Table 2 features suggestedplanting weeks for some of the popular vegetativeannuals.

Preventative Substrate Drenches

Drenching the substrate with Aliette,Banrot or SubdueMaxx is a preventative measure for pathogenicinfection from Rhizoctonia, Thieleviopsis, Pythiumor Fusarium. Certain fungicide drenches are onlyspecific for certain species of fungi; reading thefungicide label before drenching is recommended.The application of a fungicide drench should beconducted 4 to 7 days after transplanting. Applying afungicide at planting may sometimes stress cuttingroot growth due to the powerful chemical dosage inthe formulation. Root systems can sometimes beharmed through chemical burns of the root hairs andsecondary roots, which damage the ability of the rootsto absorb nutrients and water.

Irrigation and Water QualityWater management is highly important during thecutting establishment phase because saturated soilscan stall growth, introduce disease and nutritionalproblems, and delay crop time. Spring production inthe mid-Atlantic usually involves overcast weather,especially in the months of February and March,therefore growers should limit overhead irrigation tothe morning for adequate drying. Spot-watering is

Volume 49, Number 3

also very effective during cloudy weather in reducingexcessive moisture in the greenhouse.

Water quality can be a problem to some mid-Atlanticgrowers who experience high alkalinity (>180 ppmCaCO^), as it contributes to a high root substrate pHand subsequently insufficient micro-nutrientavailability. Bacopa, brachyscome, calibrachoa, andsnapdragon respond better to a low pH (5.5 to 5.8)root substrate. High alkalinity and a high root substratepH (6.0 to 6.6) can lead to iron deficiency. To combathighalkalinity,growers shouldapply acidic fertilizerslike 20-10-20 to the crop or inject acid into theirrigation water. Please visit http://www.ces.ncsu.edit/depts/hort/floriculture/crop/crop_water. htm todownload a free acid injection calculator. Geraniums,strawflower, dahlia, and fuchsia are known for theirhigh pH requirement (6.0 to 6.6) and can develop ironand manganese toxicity symptoms if the root substratepH is low.

Humidity ControlNot only can high humidity in the greenhouse increasethe incidence of disease, but it can also inhibit thetranslocation ofcalcium inplants. Another unfortunateresult ofhigh humidity is the presence of small bumpson the foliage and stems on certain vegetative annualssuch as ivy geranium, princess flower, heather, andsweet potato vine. The problem is termed edema, aplant condition where the uptake of water is greaterthan the transpiration rate. The use of horizontal airflow fans and limiting irrigation during cloudy periodswill help prevent edema.

Root Substrate

Selecting the proper root substrate is extremelyimportant to successful vegetative annual production.An ideal substrate for vegetative annuals should allowfor rapid root development, while maintaining goodwater holding capacity. Mixes which stay too moistmay cause shoot growth to become weak and chloroticdue to the lack of oxygen in the substrate. Thechances for root rots to occur are greater in substrateswhich are continually saturated.

PlantingVegetative annuals can be planted in pots as small as4 inches, large gallon containers or hanging baskets.Pot size is important for two main reasons: it influencesthe number of cuttings required per pot and thenumber of production weeks (Table 2). One plant perpot is recommended for 4-inch pots while 2 plants per

N.C. Flower Growers' Bulletin - June 2004

• pot isrecommended for 6-inch potsand larger. Rootedcuttings should be planted 1 to 3 inches apart.

Dibbling is an important practice used to establishvegetative annual cuttings more quickly. The size ofthe dibble hole should not be deeper than the depth ofthe root ball, nor wider than the root ball. Deep holesmade by an aggressive finger will only increase thechances of crop failure. Using one's finger sometimesisn't the greatest tool for dibbling, but then again, asense of depth for rooted cuttings will enable thedibble to hole to be ideal for cuttings and uniformityof the hole depth will occur for all containers.

SpacingOnce leaves begin to expand laterally beyond thesides of the pot, vegetative annuals should be spacedaccordingly to avoid stretch, lower leaf drop, and thepossibility of disease from reduced airflow betweenplants. For most vegetative annual species use 6 to 8-inchcenters for 4-inch pots, 12 to 14-inchcenters for6-inch to gallon size pots, and 24-inch centers forhanging baskets.

Plant Growth RegulatorsMostPGRsareeffective as foliar sprays incontrollingheight of vegetative annuals. Applications should bemade 2 to 3 weeks after pinching or when foliagereaches the pot rim. Foliar sprays of B-Nine at 1,500to 3,000 ppm or Cycocel at 750 to 1,250ppm alone oras a tank mix with B-Nine are excellent chemicals to

trial initiallyon vegetativeannuals. Trialing a smallgroup of plants before treating entire crops with thetriazole type PGRs Bonziand Sumagic is suggested;check the label for species specific rates and legalmixing information. Please visit the NC State Webpage www.pgrinfo.com to download a free calculatortoattain accurate application rates. Substratedrenchesare also effective with vigorous species such ascalibrachoa, petunia, and scaevola.

With the new chemicals, Piccolo and Topflor on themarket, researchers atNorthCarolinaStateUniversityhave conducted several PGR trials on vegetativeannuals. Refer to Table 3 for recommended chemicalrates for select vegetative annuals.

Florel is anotherPGRcommonly used on vegetativeannuals. A 500 ppm concentration is recommendedon geraniums with lower rates (200 to 300 ppm)suggested for calibrachoa, diascia, lantana, nemesia,petunia, scaevola, and verbena. Bacopa, double

Volume 49, Number 3

Table 3. Recommended PGR Foliar

Sprays for Select Vegetative Annuals.

Species Chemical

Rate

(ppm)

Angelonia SumagicTopflor

10-20

40-60

Argyranthemum SumagicTopflor

10-20

50-75

Calibrachoa Bonzi/Piccolo

Sumagic20-30

10-25

Colcus Bonzi/Piccolo

Sumagic5-30

10-20

Nemesia Bonzi/Piccolo

SumagicTopflor

10-20

5-30

2.5-5

Petunia Bonzi/Piccolo

SumagicTopflor

5-45

20-50

15-60

Scaevola Bonzi/Piccolo

SumagicTopflor

20-40

30

45-60

Verbena Bonzi/Piccolo

Sumagic5-30

15-30

impatiens, and New Guinea impatiens respond wellto Florel at 100 to 200 ppm. Florel should not beapplied to torenia because it delays flowering andwith angelonia tip burn can occur.

PGR Overdose Correction

Certain vegetativeannuals like NewGuinea impatienscan become stunted in the finished container due to

the misapplication of PGRs. The gibberellin-containing PGR Pro-Gibb has been shown to reversethe negative effects caused by improper PGRapplications. Results vary by crop and the severity ofthe overdose. Initially trial 1 ppm and repeatapplications on a 5 to 7 day interval if needed. Onpoinsettias, Fascination (a GA + BA combination)has been used at 3 ppm to promote more "controlled"growth. Growers should conduct trials to determineoptimal rates for vegetative annuals.

TemperatureNight temperatures prior to pinching for vegetativeannuals should be between 63 to 68°F for proper root •

N.C. Flower Growers' Bulletin - June 2004

• establishment. Producing vegetative annuals in houseswith the same night temperature requirement shouldbe a common practice among growers. In generalthere are three groups of vegetative annuals: cool,moderate, and warm (Table 4). In general daytemperatures should be set 5 to 10 degrees higher thanthe night temperature.

Lighting/PhotoperiodMost vegetative annuals are either day-neutral orfacultative long day plants. Refer to Table 5 forphotoperiod categories of select vegetative annuals.Supplemental lighting (14 to 16 hours) is required forsome species like petunia and calibrachoa to achieveearlier flowering. Incandescent lights are typicallyused to extend the daylength or provide nightinterruption, unfortunately using this type of lightingincreases the incidence of intemode elongation anddecreased branching. Growers should invest in highintensity discharge (HID) lighting (better light quality)to improve plant quality. Off-peak electricity ratesoffered by the electric company will reduce nightlighting costs.

Pinching and TrimmingPinching may be required to achieve uniform shootdistribution of the finished plant ofsome crops. Thin-stemmed crops like bacopa, diascia, evolvus, andnemesia may require multiple pinches to producedense growth in containers and baskets. Growersshould evaluate cutting costs and the time involved inproducing a hanging basket crop, because it may beadvantageous to install more cuttings in the basket toreach the market date than to pinch certain speciesmultiple times. Pinching usually increases crop timeby a few weeks. Thicker-stemmed crops such asargyranthemum, brachyscome, bracteantha, andsnapdragon will require a pinch two weeks afterplanting to ensure adequate root establishment. Asharp instrument should be used when pinching thickstems; sanitize the blade with a 109r Chlorox solution

between each plant to prevent disease transmittance.

Fertilization of CropsFor the vegetative plug stage, fertilize with N at 75 to100ppm using aconstant liquid feedprogram. Duringactive growth, rotate weekly between 15-0-15 and20-10-20. By rotating these two soluble fertilizers,growers can provide calcium and low phosphorusamounts with the "Dark Weather Feed" (15-0-15)and adequate micronutrients and ammoniacal-nitrogenwith the 20-10-20. Anotherexample would be weekly

Volume 49. Number 3

• - •

Figure 1. Whether large or small, display gardens arean essential component in an effective marketingstrategy.

fertilizer rotations of21-5-20(an acidic fertilizer) and13-2-13 (a basic fertilizer). For most vegetativeannuals constant liquid feed applications of 150 to200 ppm N are suitable.

Fertilizers such as 13-2-13, 15-0-15, and 21 -5-20 arelow in Pand ideal for vegetative annuals because highlevels of P have been shown to increase stem

elongation, promote flowering, and are toxic to someof the native Australian species such as scaevola andargyranthemum, High levels of NH -N(> 40%) and/orurea ina fertilizer mix should be avoided to preventexcessive stem elongation.

If crop fertility is not properly managed, nutrientdisorders can arise. Please visit www.ces.ncsu.edit/

floriculture/def/ to view deficiency symptoms andnutrient disorder corrective procedures of 11

Table 4. Production Night Temperaturesof Select Vegetative Annuals.

Cool Moderate Warm

(50 to 58°F) (58 to 65°F) (65 to 70°F)

Argyranthemum Bacopa AngeloniaBrachyscome Calibrachoa Lantana

Diascia Coleus Pentas

Nemesia Fuchsia Scaevola

Osteospermum Petunia Strobilanthes

Snapdragon Portulaca SweetpotaloVerbena Scaevola Torenia

N.C. Flower Growers' Bulletin - June 2004

P" vegetative annuals. Visual diagnosis is a popularmonitoring tool, however using a plant diagnostic labto identify the source of nutritional problems is stillthe best way to ensure accurate diagnoses, since manynutritional, physiological, insect and disease problemscan mimic each other.

Nutritional MonitoringThe root substrate pH and electrical conductivity(EC) should be monitored on a bi-weekly basis becauseof the potential of salt accumulation and/ or thedevelopment of high or low pH values. Todd Cavins,Assistant Professor at Oklahoma State University hassuggested use of a pH and EC matrix to manage thenutrition of vegetative annuals (Table 6). An ideal pHrange for most vegetative annuals should be between5.8 and 6.2 and EC levels during active growth shouldbe maintained between 1.8 to 2.7 mS/cm based on the

PourThru extraction method. Growers can visit

www.pourtbruinfo.coin fordetailed information aboutthe PourThru method. The use of a slow release

fertilizeris recommended ifplantsare grown outdoors;side-dressing the plants before sale is alsorecommended for post-harvest considerations in thelandscape or containers.

Hanging Basket CultureProducing hanging baskets of vegetative annualsinvolves similar production protocols to smallercontainers, however growers should consideradministering the following strategies to extendpostproduction quality. (l)To avoid the center foliageof the basket from becoming thin and scraggly, leaveroom in the center at planting for light to penetrate theinterior of the canopy. (2) Growers should alsoconduct routine soft pinches on trailing- type speciessuch as bacopa, bidens, and scaevola. (3) Invest in amicrotube irrigation system as opposed tohandwatering to improve crop uniformity and avoidthe negative results of overwatering. (4) Considerdrenches of Bonziand Sumagic to vigorous, trailing-type crops to reduce legginess in the later weeks ofwholesale production and the retail environment. (5)Improvepostharvest lifeby incorporating slow releasefertilizers (Osmocote or Nutricote) into the rootsubstrate.

MarketingUnfortunately marketing sometimes falls by thewayside after a rigorous production and shippingschedule. The good news is plant suppliers havealready performed muchof themarketingofvegetative

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Table 5. Photoperiod Categories ofSelect Vegetative Annuals.1

Short Day2 Day-Neutral Long Day

Dahlia*

Pleetranthus*

SweetpotaloSlrobiianlhcs

BacopaColcus

Scaevola

Verbena

Begonia*Calibracoa

Mimulus

Petunia*

'Category to flower or produce lubcrs-Light for continual vegetative growth'Some types or cultivars

annuals, including the research, establishment of atarget market, and preparation of point-of-purchase(P.O.P.) materials. Plant suppliers are attempting tocreate a pull-through economy, where consumers askfor their products by name. Plant suppliers alsorealized that growers are too busy producing qualityplants to design integrated marketing programs. Byproviding stock to retailers and then supplying P.O.P.materials combined with national advertising onHGTV and the Weather Channel, brands like Proven

Winners, Flower Fields and Simply Beautiful havebeen recognized by consumers.

RetailingGrowers should take advantage of the huge colorrange in vegetative annuals to produce attractive in-store and garden displays. Whether large or small,display gardens are an essential component in aneffective marketing strategy (Figure 1). Select abalanced group of tall and upright plants, sprawlingmoderate growers, and trailing prostrate plants.

Landscapes have influenced homeowners' tastes byadding lots of large, colorful plants to subdivisionentryways and corporate landscapes. Bydemonstrating the proper way to display vegetativeannuals, landscapers have shown consumers the valueof purchasing large, vivid, and texturally stimulatingspecies. Furthermore, landscapes aren't afraid tochange the landscape palette frequently by removingtired plants and replacing them with eye-catchingvegetative annuals. Homeowners have begun toadopt this "rip and replace" mentality, and this canonly benefit the retailer.

Always have fully-stocked benches, provide lots ofcarts and baskets for easy shopping, and make surethat prices are always prominently displayed. ^

N.C. Flower Growers' Bulletin - June 2004

• Remember that signage is an excellent salesperson,but there is no substitute for personal customer service.Retailers should also team up with local "horticulturalgurus", such as newspaper columnists, arboretumdirectors, or universities, to provide regionalrecommendations. Offer "Employee Picks" at yourgarden center. Promote "rip and replace" landscapesto local landscape firms by offering discounts on bulkorders. Hold monthly workshops that incorporateseasonal vegetative annuals. Personalize your gardencenter by integrating your own creative ideas intocorporate marketing resources.

Resources

Books

• Ball Red Book, Volume 2, 17th ed. Edited byDebbie Hamrick

• The EuroAmerican Container Garden Cookbook byKerstin Ouellet

• Contain Yourself by Kerstin OuelletAvailable from Ball Publishing Bookshelf. Contact:(888) 888-0013 or www.ballbooksbelf.com.• Tips on Growing Vegetative Annuals by JohnGaydos, Steve Jones, Jack Williams, and Mark Wilson.• Tips on Designing, Growing, and Marketing MixedBaskets and Containers by Terri Starman, KathyPufahl, and Peter Konjoian.Available from OFA. Contact: (614) 487-1 117 orwww.ofa.org.

Manuals and Photocards

• Vegetative Annual Manual, North Carolina StateUniversity and the North Carolina Commercial FlowerGrowers' Association have teamed up to publish a79-page Vegetative Annual Manual. It includes thelatest information on production and marketing.• PICT Guide to Vegetative Annual Disorders,Crompton-Uniroyal,MasterTag, North CarolinaStateUniversity and NCCFGA have teamed up to publishPICT Guide to Vegetative AnnualDisorders. The 54-page guide containsover 70 photographs of insect, disease,nutritional, and physiological disorders.Available from NCCFGA. Contact:

(919) 334-0093 or www.nccfga.org.

Internet Resources

Please visit the following plant supplierWeb sites to view the latest cultivar.

Volume 49, Number 3

production and marketing information.• Ball- www.ballfloraplant.coin

• Bodger- www.michells.com/Bodger.htm• Euro American- www.eiiroaniprop.com• Fisher- www.fischeritsa.com

• Flower Fields- www.tbeflowerjields.com• Gro Link- http://www.iirolink.com/

• HMA- www.hmaplants.com

9Oglevee Ltd.- www.oglevee.com• Paul Ecke Ranch- www.ecke.com

• Proven Winners- www.provenwinners.com• Yoder Brothers- www.yoder.com/

Please visit the following Web sites for productionand marketing information.

•Retail Reflections, NorthCarolina State University-www.floricultureinfo.com• Floriculture Information Center, North Carolina

StateUniversity, http://www.ces.ncsu.edu/depts/hort/floriculture/crop/crop_prop.htm• Vegetative Annual Database, Texas A&MUniversity.http://aggie-horticulture.tamu.edu/floricultitre/index, ht nil

http://horticulture. taniu. edit: 7998/vegetativeannual/search.html

• Production Guidelines for Four New Crops,University of Massachusetts, http://www.umass.edu/uniext/floricitltiire/fact_sheets/speci(ic_crops.htinl

Recommendations for the use ofproducts are included in thispublication as a convenience to the reader. The use of brandnames and any mention or listing of commercial products orservices in this publication does not imply endorsement 1>V

University of Florida and North Carolina Slate University nordiscrimination againstsimilarprodiu-isorsen-ices notmentioned.

Table 6. pH and Electrical Conductivity (EC) Matrixfor Select Vegetative Annuals.

Low pH Mod. pH High pH

Low EC Colcus Impatiens—

Moderate EC Nemesia Verbena Geranium

High EC Petunia Scaevola ...

sl