New York State Flower GrowersINC ORPORATED

BULLETIN 25 Secretary, Harold B. Brookins, Orchard Park, N. Y. SEPTEMBER 1947

REMOVING HYDRANGEA LEAVES ANDHYDRANGEA FUNDAMENTALS

Kenneth Post, ProfessorDepartment of Floriculture and Ornamental Horticulture

Easter l$k$ Is March 2B. A few fundamentals may help you to flower plants with little extra forcing. The Information which Isfundamental has been worked out over thepast several years and when pieced togethermakes a complete picture of the pre-forclngand forcing treatment.

Faotors Influencing bud formation are(1) temperature, (2) light Intensity, (3)foliage area and exposure to light, (k)vigor of the plants and (5) length of thevegetative shoot.

Bud development, after buds have once

DEGS.

t.

50

Average datefor last -cinch

July 15

Normal Mean

formed, is Influenced by (1) storage temperature, (2) light Intensity and (3)presence or absence of foliage.

Bud growth during the forcing period IsInfluenced by the conditions under whichplants formed and developed buds and (1)temperature, (2) moisture, (3) fertilizerand (4) light during the forcing period.

BUD FORMATION

Hydrangeas require a temperature below650 for flower bud Initiation. It Is not

(continued on page 3)

Buds initiatestarting I9I+6

Oct. 1

MEAN DAILT TEKPERATOEE

AT ITHACA, N. T.NOBMAL AND 1946

Possible last

pinch 19kSAug. 15

Buds initiatestarting average

Sept. 1

Dark storageaverageOct. 15

Safe date forstorage I9U6

Nov. 15

10

10 20 30 10

JULY

t20

AUG.

30 10 20 30

SEPT.

\10

t

20

OCT.

t

30 10

r20

NOV.

30

\

10 20

DEC.

30

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known if this is the night temperature onlyor if It Is the average temperature but theevidence points to 650 as the average maximum temperature below which flower buds Initiate. This Indicates that bud formationstarts when the night temperature is near 5° •

The exact date when the temperature isbelow 650 varies in different parts of theU.S. and It varies In the same locality fromone year to the next. The accompanyingchart for Ithaca shows the average temperature for several years and the actual averagedally temperature in 19I16. We have madethe chart large so you can plot your localtemperature on it.

We do not know what effect one or a few

cool days, Interrupted by one or a few warmdays, has on bud formation. Probably theeffect Is similar to the Interruption of theshort day treatment of chrysanthemums. Ifthe temperature is low more than half thetime each week buds probably form.

About one month of low temperature appears necessary to oomplete the formationof hydrangea flower buds. Usually buds arewell developed by October 15 at Ithaca. In19^6 they were not developed until November15 because of high temperature. This probably varies with varieties and all otherfactors Influencing growth.

Experiments made at Cornell (CornellBulletin #7J$7) show the leaves must bepresent and functioning in the presence ofsunlight during the entire bud formingperiod. Leaf removal by hand picking orgassing and heavy shade or complete darkness, during the early part of the lowtemperature period, prevented buds fromforming. Foliage heavily infected with mildew or an early frost will probably likewise render the foliage valueless and mayresult in blindness.

The terminal growing points of the shootsmust be active or buds fall to form. If theplants are pinched late, so that growingpoints are not developed when the temperatureis reduced, no budB will form. The date forthe last pinch is then closely associatedwith the time the temperature is loweredfor bud formation. About 6 weeks should beallowed between the date of the last plnohand the time the temperature drops for thebeginning of bud formation. At Ithaca theaverage date of the last plnoh on most varletieB is near July 15 to August 1. The lastpinch could have been made August 15 in 19^6.Your last pinch may be earlier or later thanthie depending on when your temperaturelowers for flower bud initiation.

Thin shoots, chlorotlo plants, and plantsnot growing because of lack of fertilizer orwater, during the bud forming period, oftenproduce blind shoots. This is because thefoliage Is not functioning properly or thegrowing points are not elongating.

Blindness

Blindness of hydrangeas like the blindness of chrysanthemumb, the splitting ofcarnations and many other greenhouse troubles, has been attributed to everythingwhich one does to the plant. With hydrangeas all of these factors may contributeindirectly to blindness.

To avoid blindness In hydrangeas makecertain the plants have young actively growing tips and no mildew on the foliage whenthe average temperature lowers below 6^.Expose the plants to full sunlight, do notcrowd them and make certain the foliage Isnot injured by frost or other means for atleast four weeks at an average temperaturenear 6o°. (Night temperature near 50°).At the end of this time flower buds, encasedin leaves, are in evidence at the growingtips.

Blindness will result if these growingtips which hold the flower buds are Injuredor removed any time previous to forcing.

Dormancy Period

After the buds form In the fall they appear to become dormant. Certain changesare taking place during this time which permit the bud to grow when the temperatureincreases. The storage time neoessary before plants can be forced can be shortenedby storing the plants in the dark at 330.Buds muBt be well formed before they areplaced in storage. Allen's work reviewedIn Cornell Bulletin 7^7 shows that darknessalone hastens the development of the flowerbud to the forcing stage. Constant temperature between 320 and ^0° further hastens thedevelopment of the bud.

Leaf Removal

Plants placed In the dark lose theirleaves over a long period of time. If theseare allowed to drop in the storage room andare not removed they rot and often cause the

Left, leaf drop produced by ar>ple gas.Right, not treated.

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rotting of stems and buds. The fallingleaves should be picked from the plants atleast each week. This Involves considerablelabor.

During the past three years we have beenexperimenting with apple gas to remove theleaves. The treatment Is the same as thatdeveloped for the removal of leaves fromrose plants.

The hydrangeas are placed in an air tightstorage room. One to two bushels of ripeapples are placed in the room for each 400cubic feet of air space. The temperature ismaintained at a minimum of 70°. A fan shouldbe used to circulate the air in the room topermit uniform distribution of the gas.Four days in this closed case and the foliage usually drops when the plant Is shaken.If the foliage has not loosened by this timethe apples can be left a few days longer.If some leaves are dropping at the end of thefourth day the treatment can usually be discontinued and leaf fall will be complete infour to eight days.

The apples should be real ripe. Windfalls are preferred. We have had no injuryto the buds of hydrangeas when one bushel ofapples were used per 100 cubic feet of airspace for four days. Some injury to thebuds did result when plants were left withthis concentration for ten days.

The apples give off ethylene gas which isresponsible for the leaf drop. The pureethylene gas could probably be used to accomplish the same result. Most storage shedsare not sufficiently tight to hold gas for along time and the apples give a continuouslow supply over a long period.

Last fall this treatment was carried outon several thousand plants in two storagesheds at the Dauernhelm Corporation Greenhouses, Wantagh, L.I., N.Y. Mel Dauernhelmused 75 bushels of Macintosh windfalls in a27,000 cubic foot storage shed. The appleswere run into the shed on a truck and a fanused to circulate the air. Leaf fall waswell underway after four days and the plantswere completely cleaned of foliage in oneoperation. No buds were injured and theplants forced uniformly and easily.

Forcing

This year plantB with well developed budsby October 15 will flower easily for Easter.Store the plants in the dark after buds areevident. Maintain a temperature of 32 to 40°or as cool as possible. Remove the leaveswith apple gas if you like to save labor.

Take plants from storage after Christmasand grow them at 6o° from the start. Keepthe soil moist preferably by automatic watering (New York State Flower Growers Bulletin23). Fertilize the plants to carry a uniform medium fertilizer level. Give themfull sunlight.

Welcome New Members

ACTIVE

CattaragusRobert Westendorf, Peter Pan Flower Shop,

Seneca Hts., Gowanda

ChemungMTrTeT. Miller, Miller's Glad Gardens, 16

Cobbles East, Elmira

TiogaJohn W. Whltmarsh, Evergreen Florist,

Spencer

ASSOCIATE

California

Clarence M. Araling, AmllngBros., P.O. Box3571 Santa Ana

District of ColumbiaJames D. Paul, Paul's Wholesale Florist Co.,

1414 Eye St., N.W., Washington

Missouri

H. R. Mueller, 16 S. Ninth St., Columbia

New York

E. S. Blauvelt, RavenaGeorge McCarthy, Long Island Fl. Supply,

39 W. Graham Ave., Hempstead, L.I.Jerome J. Parker, 1187 E. 214 St., Bronx 67David H. Walbolt, Shell Chemical Co., 1479

E. 26th St., Brooklyn 10H. Weezenaar, Jr., Hudson Trading Co.,

Highland

Ohio

William N. Nye, 528 Second St., Marietta

England

Alfred Wheatcroft, Wheatcroft Bros., Ltd.,Ruddlngton, Nottingham

Palestine

Rebecca Breizman, Meshek Poalot, P.O.B. 63,Petach - Tikva

Fossum at Purdue

M. Truman Fossum, Fellow of the New YorkState Flower Growers, left Cornell September15 to continue his studies in agriculturaleconomics at Purdue University, Lafayette,Indiana. We are looking forward to his return to Cornell in 1948 to continue his research and direct the research In the economics of florists crops.

During the past month two fellowshipswere granted Cornell University by theSociety of American Florists for additionalwork in the field of economics of floriculture. These fellows will work under thedirection of Professor Fossum In compilingstatistics about the florist business froma national standpoint. The New York StateNurserymen'8 Association is supplying fundsfor travel and maintenance for one assistantto obtain statistics of the nursery businessIn New York State.

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THE SOUTH AND WESTA sabbatic Is a rare opportunity for pro

fessional improvement. Travel Is alwaysenlightening and during the last six monthsyour editor visited some of the high spotsin the South and West.

Optimism and enthusiasm for expansion inall phases of production reigns supreme inthe minds of growers. Improved efficiency,mechanization and the application of scienceto production methods are giving more economical production. Greater specializationin production and selecting a location bestsuited to the production of the specificcrop are definitely the trend.

Air transportation to and from all partsof the world is causing some concern. Thisalong with the possibilities of creating alarger flower buying public is stimulatinginterest In expansion.

Much of the expansion in cut flower production Is in field grown material. Fieldgrowing Is most popular In the southernpart of the U.S. because weather conditionspermit production for the winter market.

It 1b evident that few of the new operators know the factors influencing the growthand flowering of the plants they are dealingwith. Because of lack of 6uch informationthe development of the Industry is by thecostly trial and error method.

Most operations are of a large scalegambling type. Many of the new operatorsare headed for failure before they plant thefirst crop. Weather conditions in the Southare hazards to winter production. If everything is favorable the crop Is very good butIf low temperature, rains or some favorableconditions for disease arise the grower isnearly helpless to save his crop. One canreadily see these factors are going to produce quantities of material at times andshortages when conditions are less favorable.We can probably expect greater peaks andgreater valleys In the price curve than wehave previously seen because of a greaterInfluence of weather conditions on the production than results when the production Isunder glass.

The 1946-47 gladiolus production inFlorida Is a striking example of weather effects. Plantings made for February cuttingsflowered in 60 days rather than the planned90 days and were cut at the same time asflowers planned for earlier bloom. Thisgave heavy production of low quality at thefirst of the year. Later cool weather delayed growth giving a period of poor production and good prloes.

Striking examples of disease ruining thecrop are always evident. Plantings of pomponsIn the field last year were ruined withfoliar nematode In Florida and with ruBt inCalifornia. The flower break, caused by avirus, on stocks in Southern California lastwinter completely ruined some plantings andcaused serious losses in others.

Lack of knowledge about fundamentals ofthe production of a given crop Is evident >where growers have attempted to grow chrysanthemums in Florida. The daylength thereis quite different from that In more northernlatitudes. Buds evidently form over a longperiod of time but they develop very slowlyor not at all. This gives hard stems whichapparently do not take up water after theyare cut. It likewise produces a much branchedand uneven flowered spray. There is no fundamental reason why chrysanthemums cannot beproduced every day In the year in every partof the world If daylength and temperatureare accurately controlled.

Stocks in California are planted duringthe fall and early winter. If the temperature Is high at the beginning of the growingperiod long stems develop before buds form.Later plantings, which are affected by lowtemperature early, form buds and flower onshort stems. Last spring fields of stockswere not cut because they were too short.

High quality cut flowers are, however, being produced In the field when all factorsare controlled. Expansion will doubtlessoccur In the production of gladiolus andchyrsanthemums in Florida, and chrysanthemumsin Texas and California. Carnation production out of doors near Los Angeles is moatlikely to expand rapidly and so long as flower prices in general remain high we can expect a continued increase in the field ofproduction of miscellaneous flowers in allparts of the U.S.

Probably orchid production is expandingmost rapidly of all production under glass.Plant prices are extremely high and thebusiness appears to be running the course ofthe tulip mania In the seventeenth century, *the gladiolus after 1920 and the Northwestlily in 1940. This le especially true withcymbidlums in California. Amateurs can growthem under lath and commercial operators insouthern California are producing them bythe acre. The ease of shipping and fairquality produced by this method will doubtless be felt in eastern markets.

The South and West Is truly a land ofopportunity for flower growing. Much effortand money will be lost by those improperlyinformed about environmental conditions andplant reactions to these conditions. In mostareas their best markets are local. The pastand present population shift makes thesemarkets increasingly attractive.

Your editor1