AmaryllisAI Pertuit

Horticulture Department, Clemson University

Anyone who knows meknows what my favoriteflower is the amaryllis.Growing up in BatonRouge, my adjacentneighbor bought newDutch hybrids annually,hybridized them, and hadhundreds in his yard. Iremember the year myyounger brother and his

friends, playing swashbucklers, decapitated the scapesbefore they had a chance to open. Talk about "hellbreaking loose!"

At LSU, the pomology professor for whom I workedas an undergraduate (Gary Couvillon's major professor at the time), was really a floriculturist. Amaryllisoccupied about a third of his "fruit" greenhouse. Hisenthusiasm for amaryllis furtherstimulated my interest. He was agreat teacher in and out of theclassroom. Years later, he followedhis heart and switched (officially) tofloriculture.

Except for when I was in the Army,I've always managed to carry a fewamaryllis bulbs along with me. Ihave a couple of hundred in my yardsome cultivars but mostly crossesI've made.

/••'•, 'v:.i.., •

flowers, the retail value of one scape being roughlyequal to that of a large bulb!

In the U.S., the name "amaryllis" generically refers tocommercially important bulbs, even though the bulbsmarketed in the trade are derived mainly from plantsof the genus Hippeastrum. (meaning: "horse star" inGreek), now the accepted genus of the hybrids that wegrow commercially. Some, however, still use thegenus name Amaryllis for the Dutch hybrids. "Amaryllis" is the common name, Hippeastrum the botanicalname. Amaryllis is the generic name for A. Belladonna; but, crinium is no longer A. bulbisperma, it'sCrinium bulbispermum; lycoris is no longer A.radiata, it's Lycoris radiata, etc. The Hippeastrumspecies name is listed in England as hybrida, but hereit's vittatum.. Many people simply give the cultivarname (e.g., Hippeastrum 'Bouquet').

In the lower South, it is common tosee outside large clumps of amaryllisbulbs, their flowers trumpet shaped,looking much in shape like an Easterlily flower. Their color is red with awhite stripe or white with a redstripe. These are the "Mead strains,"developed in Florida by Dr.TheodoreMead. Their parentage includesbulbs imported from England and thecontinent by Dr. Henry Nehrling.Outside, these bulbs often grow inlarge clumps which add a lot of colorto the landscape. Although the Meadtypes come true from seed, they arenot as striking as the Dutch hybrids:their color range is very limited,andtheir flower form is considered

inferior to the Dutch hybrids. Thepetal/sepals of the Dutch hybrids arefar wider and more refiexed than the

Mead types, making their flower wider in diameter andflatter than the Mead types.

The Dutch hybrids come in many colors and variouscombinations and tints and shades of them: white, red,pink, orange, and, just recently, yellow. Some of therose pinks exhibit a blue tint in their petals. A yellowspecies (H. Evansiae) was discovered in Bolivia about35 years ago. It is a relatively small bulb (ca. 11/2 inch

So, I've found it exciting to see thepopularity of the amaryllis increaseover the past decade. I rememberwhen American Express first beganoffering them for Christmas. Now,amaryllis are even becomingpopular for Mother's Day andEaster. In fact, they're so common now that onesimply has to go to the produce section of his localsuper market to purchase one. One SC greenhouseoperation uses the amaryllis for its logo.

Fig. 1. Hippeastrum capsuleswith seed - ready forsowing

Although they're not cheap, in our area they willperformwell outside (even producing offshoots) yearafter year, unlike the undependable tulip. Undeveloped scapes occasionally are sold wholesale as cut

Page 42, Georgia Floriculture

35 years ago. It is a relatively small bulb (ca. 11/2 inchin diameter, maximum) with flower of only an inch indiameter. It's taken quite a while to incorporate theyellow into the larger flowering yellows availablecommercially.

The flowers are produced (2-6) inan umbel arrangement [i.e., stems(pedicels) of florets attached atsame point on main axis (peduncle)] on the scape (i.e., aleafless, hollow stalk that originatesat ground level). The scape'srapidity of development is trulyamazing... from being just visible atthe bulb's nose to as much as 3

feet long in a few weeks! Individual flowers of 11 inches in

diameter may open. In somecultivars, the leaves emerge fromthe bulb with the scape, but inothers, leaf emergence from thebulb follows flowering. Often,more than one scape, usually 2, willdevelop and flower simultaneously.Regardless, another scape usuallydevelops 2 to 3 weeks after the first floral display.Each flower may develop into a fruit (capsule) whichmay contain over 100 seeds. Seeds are a good place tobegin discussing amaryllis culture.

The capsule, after turning yellowish, will begin to splitabout 6 weeks after the flower opens, revealing itsblack seeds (Fig. 1). At this stage, the highest percentgermination will be attained... thelonger one keeps the seeds afterthis point, the fewer will germinate.Seeds not planted right awayshould be kept in the refrigeratoruntil sowing. Seeds removed fromthe capsule may be floated overnight in a bowl of water beforesowing. They may be sown thickly(i.e., seeds touching one another)about a quarter of an inch deep inbuilder's sand. In less than two

weeks, the surface of the sand willbe covered with small leaf blades.

Continue to water them. The sand

insures good drainage, so theywon't rot. A tiny bulblet is evidentwith the formation of the second or

third leaf. After a month, acomplete liquid fertilizer of about 200 ppm N isrecommended, which may be increased to 500 ppm Nat 4 months. After 6 months, 700 to 800 ppm N is

Fig. 2. Scapes withinthat has been cut

mid winter.

recommended! They grow like weeds!

The bulblets will probably need transplanting at the 3-5 month stage, again at 10 months, when you canintroduce each bulb to its own pot. When transplant

ing, use a mixture (by vol.) of threeparts builder's sand, four parts pinebark (soil conditioning grade), andtwo parts peat moss. The pHshould be adjusted with dolomiticlimestone to ca. 6.5. NEVER

fertilize an amaryllis bulb that hasno leaves. Amaryllis will flowerfrom seed in 3 years, occasionallyin two years... if greenhouse grown!

Amaryllis should be potted with ca.one-third to one-half of the bulb

above the growing medium surface.They do well when potted this way,and it keeps the bulb's nose dry,precluding conditions conducive to"red blotch" infection. Potted bulbs

thrive under conditions in which

they are pot bound. When pottinga mature bulb, leave only an inch

between the outside of the bulb and the inside of the

pot rim. In outside beds, the bulb should be plantedwith only half of the bulb's nose above ground. Heavymulching in the fall/winter is advised.

The life cycle of the amaryllis is extremely interesting.Seedlings do go through a juvenile stage, noted by thefact that they continue to grow relatively vigorously in

the greenhouse in winter. Thejuvenile stage probably ends withthe initiation of the first scapewithin the bulb. In winter in the

greenhouse, mature amaryllis havea "tendency" to have a rest period[i.e., a period in which visiblegrowth completely ceases becauseof internal (physiological) conditions within the plant)]. Theirgrowth slows greatly in winter, butit does not cease completely. Inthe greenhouse, if left alone,mature bulbs generally flower inthe spring, but many also flowersporadically at other times of theyear.

Hippeastrum bulbin hull" in

Fig.3. Hippeastrum flower exhibitingripe anthers

The mature amaryllis bulb initiatesflowers while growing vegetatively. Initiation of aflowering scape within the bulb is not photoperiodi-cally controlled. Research has shown, however, that

Georgia Floriculture, Page 43

very warm temperatures (e.g., >83°Fdays, >73°Fnights) increase leaf growth but reduce bulb growthand the number of scapes initiated. These conditionsare common in summer in the deep South. Ingeneral, a bulb will initiate a flowering scape followingthe production of 3 to 4leaves. It follows, then, thatthe more leaves it produces,the more scapes it initiates. Amature bulb will averageabout 12 leaves during agrowing season, producingabout 3, and on rare occasions4, scapes. If outside, growthceases in the fall as temperatures decline, and the leavesdie back. The winter is reallya dormant period (i.e., itceases growth because thetemperatures are unfavorable). This forced period ofinactive growth induces scapedevelopment (i.e., expand,take up water, etc.), and byearly spring the scape(s) willbe visible at the nose of the bulb, usually developingbefore the leaves, which do not appear until thetemperature warms up more. The winter period ofinactivity "programs" the scapes to develop in thespring. In the greenhouse, thesesame scapes might flower in latewinter or not develop untilsummer.

The interesting part of their lifecycle is that the scapes thatdevelop in the spring (i.e.,emerge through the neck of thebulb, elongate, and flower) arethe ones that were initiated

about 18 months previous, notthe ones initiated the just-previous growing season! Inother words, when it finishesflowering in the spring, thescapes initiated the last growingseason are still within the bulb

and won't develop until the nextspring. At the end of the growingseason in the rail,the bulb has within it scapes of two ages... thoseinitiated last year and those initiated the current year(Fig. 2).

In the greenhouse, one can program flowering. This isaccomplished bywithholding water from the plants inAugust and turning the pots on their sides to make

certain that no water gets into the pots. The leavesshould not be cut off. They should be allowed to dienaturally. In December, the scapes will appear at thenose of the bulb. To force them at that time, the potsare turned uprightly and the bulbs watered. Bulbs will

flower in 4 to 6 weeks in a

62 to 65°F minimum

greenhouse. They shouldnot be fertilized until their

leaves begin vigorousexpansion. For laterflowering, they can be storedat40-45°F. This 40-45°F

exposure is not a necessarypart of the plant's life cycle(i.e., it does not fulfill somerest requirement because itdoesn't have a rest requirement). This temperaturerange merely acts as anunfavorable environment for

vegetative growth and scapedevelopment. It is simply aholding temperature, andbulbs can be held for at

least a year at this temperature before forcing. About4 to 6 weeks before flowering is desired, the bulbsshould be removed from the 40-45°F storage andwatered. If they're potted during the 40-45°F storage,

the bulbs must be watered

occasionally. Bulbs alreadyrooted when removed from

storage will force faster andproduce larger flowers than bulbswhich must root during scapedevelopment. It is possible,therefore, to force amaryllis atany time of the year.

Amaryllis are extremely easy topollinate. Once the pollen is onthe stigma (Fig. 3 ), the flowerwill begin to streak and wiltwithin a day or so. Most of theseedlings produced will havestriped flowers, even if bothparents have solid coloredflowers. Also, many of the

seedlings will not have the open, flat form of their"parents" they'll be moretrumpet shaped. It is possible, however, to get seedlings equal to and occasionally better than their parent(s). In a yard, whatmatters iscolor (i.e., the mass effect), not the qualityof an individual flower.

Fig. 4. Hippeastrum bulbscut longitudinally 1/8,1/16and 1/32. All piece contain nportion of the basal plate.

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Fig. 5. Hippeastrum leaf blades infectedwith mosaic virus. Healthy-left, Infected-right.

Amaryllis do produce offshoots, some cultivars morereadily than others. Any offshoot,of course, would beidentical to its parent. Because propagators want tosell as many bulbs as possible, they prefer that cultivars not produce offshoots readily, and this is aconsideration in whether a cultivar is released com

mercially. Offshoots initiate their first scape at ca. the9-leaf stage, but often this first scape aborts.

Amaryllis may also be propagated bycuttings (i.e., bulb dissection). Onlylarge bulbs should be used in asexualpropagation. First, the bulb is cutlongitudinally (top to bottom)through its basal plate. Afterdividing a bulb in half, the halves arehalved again (total: 4 pieces), thenagain... 8, and then 16. It is possibleto continue to 32 (Fig. 4 ), etc., but itis recommended that nonprofessionals stop with 16 divisions. Each cutpiece must contain a piece of thebasal plate (stem tissue) or it will notroot because new roots develop fromstem, not leaf, tissue. The bottomthird of the cutting, which includesthe basal plate, is buried in sand andwatered. In several weeks, a new leafwill appear, then two, etc., then a newbulb will form at the base. This bulb

will flower in ca. two years. Asexual propagation likethis is how named cultivars are increased.

The main pest problems of amaryllis are mosaic virusand "red blotch". Occasionally, plants in the greenhouse will get soft brown scale, but this is easilycontrolled. Spider mite infestation is rare, but it too iseasily controlled.

There is simply nothing one can do to eliminatemosaic from a plant. Its symptom is light yellowstreaking of the foliage. Often, new leaves do notmanifest the symptom until they have elongated andmatured. Initially, a plant with mosaic may performwell, but it will have reduced vegetative growth as theyears progress. Eventually, it will not flower. Also, itserves as a source of infection of healthy plants. Themosaic virus can be spread by insects, also by cuttingan infected plant with a knife, then cutting a healthyone with the same knife. There is some evidence that

smoking tobacco in a greenhouse can produce mosaicinfection. Some believe that the virus can be transmit

ted from root to root in a bed situation. Plants

infected with mosaic do not transmit disease to their

seeds. So, if the plant produces a nice flower, onemight make a few crosses with it before discarding it.

"Red blotch" is caused by the fungus Stagonosporacurtisii (Fig. 5 ). It is very destructive and, if unchecked, progresses rapidly within a bulb and frombulb to bulb. This same disease is called "scorch" on

daffodils. The disease manifests itself by reddishbrown spots that develop into lesionson the bulb, leaves, and/or scape. Thefungus can progress into the heart ofthe bulb. The scape may rot off at theattacked location before its flowers

open. Even today, it is unfortunatelycommon for bulbs to be infected with

both mosaic and red blotch when theyare purchased.

Fig. 6. Scapes of Hippeastrum infectedat bulb nose with red blotch.

(Stagnospora curtisii)

Captan and Bordeaux mixture used tobe recommended for red blotch, butneither is very effective. Then Benlatecame along. It was extremely effectivein eradicating Stagonospora fromamaryllis. If properly timed, one sprayin early fall could eliminate the diseasefrom a moderately infected plant.Because the fungicide is systemic, theplant probably draws the fungicide intothe bulb when it translocates its leaf

carbohydrates into its bulb as its leaveswither and die. It is a good idea to assume that newlypurchased bulbs have the disease: soak them in aBenlate-like fungicide for a half an hour beforeplanting. Cleary's 3336 and Sierra's Domain maysubstitute for Benlate.

Selected Cultivars

There are many amaryllis cultivars available. Some ofthe older cultivars produce offshoots more readily thansome of the more recently released ones.

'Apple Blossom': a white flushed pink; the Americanfavorite; an older cultivarwith strong substance andideal flower form.

'Bouquet': an salmon orange with strong substance;flower form is a bit triangular, caused by its petalsreflexing too much; its color is its best attribute.

'Fantasy': looks very much like 'Apple Blossom' butwith a lot more and deeper color; doesn't have thesubstance of 'Apple Blossom'.

Georgia Floriculture, Page 45

'White Giant': aptly named; one of the largest flowersbut also with one of the longest scapes; a vigorousgrower.

'Marie Goretti': a white with frilled edges; flowershave good substance and form but not many flowersper scape.

'Doris Lillian': a deep rose pink... a favorite; goodsubstance and flower form; open flowers have a bluetint in their petals; can be hard to find.

'Wyndham Hayward': a dark red of extremelygoodsubstance and flower form; this clear red color hard tofind.

'Majuba': a scarlet with exceptional flowerform (verywide petals/sepals which do not reflex) but tall.

'Trixie': a cherry red; very good substance and flowerform; color is unique.

'Picotee Petticoat': white with red lined petals/sepals;substance and form are an improvement over 'Picotee'but they are still only a little better than average.

YOUR SUPPLIER OF:

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Page 46, Georgia Floriculture

'Red Lion': medium, clear red with verygood substance

'Yellow Pioneer': newcolor withonlyaverageflowerform.

Amaryllis References:

Bailey, L.H. 1928. Hippeastrum. The StandardCyclopediaof Horticulture, vol. II. The MacmillanCo., New York.

Bailey, LibertyHyde and Ethel Zoe Bailey, and StaffofThe Liberty Hyde BaileyHortorium. Hippeastrum.1976. HortusIII. Macmillan Publishing Co., Inc.,New York.

DeHertogh, August. 1992. Bulbous and tuberousplants. Introduction to Floriculture, 2nd Edition. RoyA. Larson (ed.). AcademicPress, Inc., San Diego.

Rees, A.R. 1985. Hippeastrum in CRC Handbook ofFlowering, vol. I. Abraham H. Halevy(ed.) CRCPress, Inc. Boca Raton, Florida.

Post, Kenneth. 1959.Florist Crop Production andMarketing. Orange Judd Publishing Co., Inc., NewYork.

Laurie, Alex, D.C.Kiplinger, and Kennard S. Nelson.1958. Commercial Flower Forcing, 6th Edition.McGraw-Hill Book Co., Inc., New York.

Pertuit, AJ., Jr. 1991. Personal notes (unpublished).Horticulture Department, Clemson University,Clemson, South Carolina.

Pertuit, AJ., Jr. 1995. Understanding andProducingAmaryllis. Hort. Leaflet63. Cooperative ExtensionService, Clemson University, Clemson,South Carolina.

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