Effects of Irrigtion Volume nd Frequency on Shru Estlishment in Florid E.F. Gilmn, C.L. Wiese 3, M. Pz 3, A.L. Shoer 4, S.M. Scheier 5, K.A. Moore 6, nd M. Brennn 7 Deprtment of Environmentl Horticulture University of Florid, Ginesville, Fl 36-675 Astrct Irrigtion frequency nd volume effects were evluted on recently instlled #3 continer grown shrus of three tx, Ilex cornut Lindl. & Pxt. Burfordii Nn, Pittosporum toir Thun. Vriegt, nd Viurnum odorotissimum Ker Gwl. Irrigtion frequency nd volume hd no effect on Pittosporum t ny time for ny mesured root or shoot prmeter. Irrigtion frequency nd volume hd no effect on Ilex nd Viurnum cnopy iomss, root iomss, root dry weight:cnopy dry weight rtio, nd stem wter potentil t ny time fter plnting. Cnopy growth ws ffected y irrigtion tretment only for Viurnum plnts instlled in My 4, nd growth response to more frequent irrigtion only occurred while plnts were irrigted, with no lsting impct on growth once irrigtion cesed. Root spred nd root spred:cnopy spred rtio for only one species, Ilex, were influenced y irrigtion tretment. Applying excessive irrigtion volume (in this cse ) reduced root dry weight:shoot dry weight rtio for Ilex nd could increse the time needed for plnts to grow enough roots to survive without irrigtion. Our study found only slight influences on shru growth from the tested vlues of irrigtion frequency nd volume regrdless of the time of yer when dt ws collected. This indictes tht these shrus cn e estlished with 3 liters irrigtion pplied every 4 dys until roots rech the edge of the cnopy under the mostly ove norml rinfll conditions of this study. Applying more volume or irrigting more frequently did not increse survivl or growth. Cnopy growth nd plnt qulity dt comined with pst reserch suggest tht estlishment of these shru species my e more influenced y environmentl conditions such s rinfll thn y the irrigtion frequency nd volume used in this test. Index words: root growth, root spred, root:shoot rtio, xylem potentil, drought tolernce. Species used in this study: dwrf Burford holly (Ilex cornut Lindl. & Pxt. Burfordii Nn ); vriegted Jpnese pittosporum (Pittosporum toir Thun. Vriegt ); nd sweet viurnum (Viurnum odorotissimum Ker Gwl.). Significnce to the Nursery Industry The different volumes nd frequencies of irrigtion pplied to the root ll nd to the smll re round the root ll hd little influence on cnopy growth or helth of #3 continer grown shrus plnted into sndy lndscpe soil under verge or ove verge rinfll conditions. Irrigting every 4 dys with 3 liters ppers to e n efficient method of estlishing shrus of this size in north Florid when verge rinfll occurs fter plnting. Applying more volume or irrigting more frequently did not increse survivl or growth. Irrigting every dys my provide for slightly more ttrctive shru in the first yer fter plnting. Introduction Too little wter hmpers estlishment nd growth of newly instlled woody plnts in the lndscpe y restricting root growth (, ) nd results in corresponding reduction in vegettive nd reproductive growth (5). Severl studies note incresed growth in response to incresed frequency of irrigtion during estlishment. However, Brnett (3) notes tht optiml frequency nd volume of irrigtion vry Received for puliction Ferury 3, 9; in revised form Mrch 9, 9. Professor, University of Florid. egilmn@ufl.edu 3 Biologists, Dept. of Environmentl Horticulture, University of Florid. 4 Assistnt Professor, Gulf Cost Reserch nd Eduction Center, Wimum, Florid. 5 Assistnt Professor, Mid-Florid Reserch nd Eduction Center, Apopk, Florid. 6 Associte Professor, Ft. Luderdle Reserch nd Eduction Center, Ft. Luderdle, Florid. 7 Coordintor, Sttisticl Reserch, University of Florid, IFAS, College of Agriculture nd Life Sciences. J. Environ. Hort. 7(3):49 54. Septemer 9 with soil type. Brnett (3) reported greter cnopy growth (4.9 ft 3 plnt volume) of # ( gl) sized Ligustrum vulgre with more frequent irrigtion nd sprser folige (. ft 3 ) with less frequent pplictions. Gilmn et l. (7) found tht incresed irrigtion frequency in wrm, moist, temperte Florid resulted in significntly greter new shoot growth, nd shifted new root growth from the ottom of the root ll to the top for Ilex cornut Bufordii Nn. Red mple responded to incresed irrigtion frequency in temperte estern United Sttes with n increse in trunk dimeter (5.8 vs. 4.7 cm), height (3.4 vs..7 m), nd new root mss (.9 vs. 5.5 g) (). Stler nd Mrtin (6) in the drier climte of Arizon found tht growth of Ceslpini pulcherrim nd Cercidium fl oridum incresed s irrigtion frequency incresed; however, trees in ll tretments grew during the study nd none exhiited signs of wter stress. Growth, mortlity, nd visul ppernce of Cenothus griseus, Rhmnus clifornic, nd Photini frseri in the dry climte of southern Cliforni were not ffected y irrigtion frequency (dily or every 3, 5, or 7 dys) following plnting; mortlity ws ffected y species rther thn irrigtion (). Irrigtion frequency ppers to e more importnt to tree estlishment thn volume pplied. Gilmn et l. (6) found tht irrigtion volume greter thn 6 liters (.5 gl) did not significntly ffect plnt growth or stem wter potentil of 5 cm ( in) cliper Quercus virginin in wrm temperte Florid; irrigtion frequency ws most importnt. Renquist () found tht pech trees were lso more influenced y irrigtion frequency thn y volume during estlishment. Similrly, chnges in irrigtion volume were not reflected in significnt chnges in growth of Photini frseri (9). Most work on irrigtion during estlishment hs een performed on trees. The ojective of this study ws to evlute impct of irrigtion frequency nd volume on shru 49
estlishment of Viurnum odortissimum, Ilex cornut Burfordii Nn, nd Pittosporum toir Vriegt. Mterils nd Methods Ilex cornut Lindl. & Pxt. Burfordii Nn, Pittosporum toir Thun. Vriegt, nd Viurnum odorotissimum Ker Gwl. otined from locl commercil nursery in.4 liter (#3) continers were plnted My 7, 4, into fine snd (Arredondo snd series) t the University of Florid s Plnt Science Reserch nd Eduction Unit in Citr, FL (USDA hrdiness zone 8). These three shrus re commonly plnted in the southern prt of the United Sttes. All shrus were plnted on.8 m (6 ft) centers with tops of root lls positioned even with surrounding lndscpe soil. Circling roots t the edge of continers were not cut t plnting in ccordnce with lndscpe industry prctices. One plnt of ech species ws rndomly plnted in ech of the five locks (5 plnts totl) Octoer 3 (seven months efore test plnts were instlled) in the sme mnner s test plnts. These more estlished plnts (clled indictor plnts) were irrigted with 9 liters every dys for 9 months to encourge rpid estlishment. Indictor plnts were used to compre ginst root to shoot rtios nd stem wter potentil of test plnts. The entire plot ws mulched with 7.5 cm (3 4 in) long pine rk nuggets to depth of 8 cm (3 in) (Florid Potting Soil, Orlndo, FL) immeditely fter plnting. A second (replicte) plot ws plnted Novemer 6, 4, in the sme mnner nd djcent to the first plot. Two irrigtion frequencies (every or 4 dys) nd three irrigtion volumes (3, 6 or 9 liters per plnt per irrigtion event) were evluted in 5 locks, for totl of 3 plnts per species for ech plnting dte in split plot design. The two irrigtion frequencies were the min plot rndomized within ech lock; species nd irrigtion volumes were rndomized within ech frequency min plot. Ech plnt ws irrigted with three uler emitters (Model Shruler 36, Antelco, Longwood, FL) clirted to deliver the desired volume. Ech emitter ws mounted. cm (4 in) ove ground level with one emitter locted on the est nd west side of ech plnt, 5 cm (6 in) from the outside of the rootll, nd the third emitter positioned on the rootll. Irrigtion ws switched on nd off using ttery operted vlve controller (Model SVC, Hunter Industries Inc., Sn Mrcos, CA). Irrigtion egn t 5 HR nd ws completed y 6 HR. Flow meters (Model C7TP, ABS, Ocl, FL) were instlled for ech frequency lock comintion to record irrigtion volume pplied. Irrigtion ws discontinued weeks fter plnting (WAP). Supplementl irrigtion ws supplied when signs of wter stress (severe wilting or eginning of lef drop) were pprent. After 33 dys with no rinfll (6 WAP) supplementl irrigtion ws pplied once in Novemer 4 to ll My 4 plnted shrus. The supplementl irrigtion pplied to ech shru ws consistent with the irrigtion volume tht shru hd received the first WAP. Supplementl irrigtion fter WAP ws never pplied to the Novemer 4 plnted shrus. Controlled-relesed fertilizer ws pplied every 3 months eginning 3 dys fter trnsplnting t stndrd rte of.45 kg N m ( l N ft ) of N.9P.6K Southern Lndscpe Fertilizer (LESCO, Inc., Sering, FL) uniformly rodcst to.84 m (9 ft ) re round ech plnt. Weeds were controlled with periodic hnd-pulling nd N-(phosphonomethyl) glycine (glyphoste). Shrus were not pruned during the study. Rinfll dt were collected with wether sttion on site. To evlute shru estlishment nd growth, cnopy height, gretest cnopy width (width ), nd width perpendiculr to the gretest cnopy width (width ) were mesured t plnting, nd t 6, 34, nd 5 WAP. Mesurements of cnopy height, width, nd width were used to clculte cnopy growth index (CGI (m 3 ) = height width width ). Slight differences in initil shru size t plnting were ccounted for y evluting cnopy growth. Cnopy growth ws clculted s follows: CGI (m 3 ) initil CGI (m 3 ). Plnt cnopy density nd dieck ws visully evluted 5 WAP on scle of (ded) to 9 (dense plnt, no dieck similr to the indictor plnts). Root spred rdius mesurements on ll plnts were mde t 6, 34, nd 5 WAP. Root spred ws mesured y gently removing the mulch lyer from section of soil pproximtely 3 cm ( in) wide just eyond the estimted edge of the root system on two opposite sides (est nd west) of the shrus from ech tretment comintion. Soil ws crefully removed y gently digging towrd the plnt until the outermost roots (those frthest from the trunk) were identified. Distnce etween the trunk nd the frthest root ws recorded s root spred rdius. Mulch ws crefully spred ck into plce. Root spred rdius to cnopy rdius rtio ws clculted y dividing root spred rdius y the cnopy rdius. Cnopy rdius ws clculted y dividing verge dimeter of the cnopy y two. Cnopy dry weight nd root system dry weight were mesured t 64 WAP. The entire ove ground cnopy ws hrvested y severing the trunk t ground level. Two /8 th wedge-shped sections (for totl of /4) of the root system in the lndscpe soil were hrvested strting t the trunk. Sustrte nd soil were wshed from the roots. Shoot nd root mss were dried t 65C (49F) until constnt dry weight ws otined. Totl root system dry weight ws clculted y multiplying the hrvested weight y four. Root to shoot iomss rtio ws clculted y dividing totl clculted root system dry weight y cnopy dry weight. Middy shoot wter potentil (Ψ w ) ws mesured on two replictes of ech tretment comintion for ll species including the estlished indictor plnts. Shoot wter potentil ws determined with pressure chmer (Model 3; Soil Moisture Equipment Corp., Snt Brr, CA) using compressed N, with pressure incresing t rte of.5 kp s. Mesurements were mde on individul stem sections ( cm long) t 9 WAP which ws two months fter irrigtion ws discontinued. Cnopy growth, root spred rdius, root spred to cnopy rtio, shoot dry weight, root dry weight, root dry weight to cnopy dry weight rtio, nd stem wter potentil were nlyzed seprtely for ech species using the MIXED procedure of SAS (Version 9., SAS Institute, Cry, NC) (P <.5). Frequency nd volume were the fixed effects. Men seprtion ws y Tukey s Test. Plnt density nd cnopy die-ck were nlyzed using the RANK nd the MIXED procedures of SAS for nonprmetric nlysis (Version 9., SAS Institute, Cry, NC) (P <.5). Men seprtion ws y Tukey s Test. Ech plnting dte ws nlyzed seprtely. Results nd Discussion Irrigtion frequency nd volume hd no effect on Pittosporum t ny time for ny mesured root or shoot prmeter 5 J. Environ. Hort. 7(3):49 54. Septemer 9
Tle. Cnopy nd root mesurements 5 weeks fter My 4 plnting of Viurnum with irrigtion frequencies nd 3 irrigtion volumes. Root Root Root spred Root dry Cnopy Cnopy spred dry rdius weight to Irrigtion Irrigtion growth Cnopy Cnopy dry weight y rdius weight y to cnopy cnopy dry frequency volume (m 3 ) density z dieck z (g) (cm) (g) rdius rtio weight rtio y Every dys 3 L.66 97. 43.5 4.5 87.67 59.73.77.53 Every dys 6 L.7 59. 5.33 56.57 93.7 477.87.8.4 Every dys 9 L.6 97. 5.33 399. 97.67 734.67..53 Every 4 dys 3 L.63 97. 43.5 5.47 97. 488.67..4 Every 4 dys 6 L.67 8. 5.33 99. 96.83 54.7.88.47 Every 4 dys 9 L.53 74.33 43.5 7.97 88.5 446.3.86.37 Irrigtion frequency.58.3.56.38.89.6.73.3 Irrigtion volume.38.* x.37.49.74.4.69.9 vs 4 dys with 3 L.85...96.3.5..4 vs 4 dys with 6 L.74.48..77.69.6.5.6 vs 4 dys with 9 L.37.3.3.4.5.3.64.5 z Density nd dieck mens were generted y the Proc RANK procedure in SAS. y Biomss mesurements were recorded 64 weeks fter plnting. x Significnce of tretment effects nd interctions *(P <.5). during the study (dt not shown). This indictes tht these shrus cn e estlished with 3 liters irrigtion pplied every 4 dys under the conditions of this study. Applying more volume or irrigting more frequently did not increse survivl or growth. Irrigtion frequency nd volume did not ffect Ilex nd Viurnum cnopy dry weight, root dry weight, root dry weight to cnopy dry weight rtio (My plnting: Tles nd ; Novemer plnting: dt not shown), nd stem wter potentil fter plnting (dt not shown). Growth of drought tolernt tree (Quercus virginin Mill.) plnted from either continers or field nursery lso did not respond to incresing irrigtion volume during the months fter plnting (6). Viurnum ws the only species with cnopy growth ffected y irrigtion tretment for plnts instlled in My 4. Viurnum cnopy growth 6 WAP ws greter when irrigted every dys thn every 4 dys ut not 34 or 5 WAP (Fig. A). This indictes tht growth response to more frequent irrigtion only occurred while plnts were irrigted, with no lsting impct on growth once irrigtion cesed. Trees lso responded to more frequent irrigtion during estlishment with incresed growth, ut the difference in size persisted for 5 yers (4). Viurnum cnopy density ws slightly ut significntly reduced when shrus received 6 liters irrigtion compred with 3 or 9 liters (Tle ). Although Ilex cnopy growth ws not influenced y irrigtion tretment, cnopy dieck ws significntly reduced when shrus were irrigted every dys compred to every 4 dys (P =.3) (Tle ). Viurnum nd Ilex instlled in Novemer 4 were slightly influenced y irrigtion tretment. Ilex cnopy growth ws greter 6 WAP when irrigted with 6 liters compred with 3 or 9 liters every 4 dys, ut not with every dys irrigtion (P =.) (Fig. B). We cn not explin why shrus would grow etter t the 6 liter volume. There ws no impct of irrigtion volume or frequency on Ilex cnopy growth fter 6 WAP. Viurnum cnopy growth ws greter when supplied with 3 liters irrigtion thn 6 or 9 liters t 34 WAP (P =.3) (Fig. C), ut there ws no impct of irrigtion on Viurnum cnopy growth fter tht. Tle. Cnopy nd root mesurements 5 weeks fter My 4 plnting of Ilex with irrigtion frequencies nd 3 irrigtion volumes. Root Root Root spred Root dry Cnopy Cnopy spred dry rdius weight to Irrigtion Irrigtion growth Cnopy Cnopy dry weight y rdius weight y to cnopy cnopy dry frequency volume (m 3 ) density z dieck z (g) (cm) (g) rdius rtio weight rtio y Every dys 3 L.9 8. 43.5 968.93 73.7 87.87.83.9 Every dys 6 L.4 8. 5.33 868.57 6.83 95.87.6. Every dys 9 L.6 8. 43.5 943.6 77.33 35.33.98.34 Every 4 dys 3 L. 97. 58.5 77.3 76.7 89.7..6 Every 4 dys 6 L. 74.33 67.7 78.97 47.33 67..5.4 Every 4 dys 9 L.4 8. 96.67 799.33 79.83 6..5.3 Irrigtion frequency...4* x..69.3.89.67 Irrigtion volume.55.6.6.78.**.58.*.57 vs 4 dys with 3 L.5.3.8.8.6.5.6.86 vs 4 dys with 6 L.57.5.3..7.7.37.68 vs 4 dys with 9 L.69..3.37.8.9.7.4 z Density nd dieck mens were generted y the Proc RANK procedure in SAS. y Biomss mesurements were recorded 64 weeks fter plnting. x Significnce of tretment effects nd interctions *(P <.5) ** (P <.). J. Environ. Hort. 7(3):49 54. Septemer 9 5
Growth (m 3 ) Growth (m 3 ) Growth (m 3 ).8.7.6.5.4.3...5..5..5.5.5 B A every dys every 4 dys every dys + 6 WAP C 6 34 5 every dys Weeks After Plnting every dys + 5 WAP every 4 dys + 6 WAP every 4 dys Irrigtion Frequency + Weeks After Plnting every 4 dys + 5 WAP ove verge for the reminder of the irrigtion period (4 WAP) (Fig. ). Aove verge rinfll continued the next 8 weeks to WAP (Fig. ) which ws 9 weeks fter irrigtion cesed. Totl rinfll the first 6 months fter plnting ws 384 mm (5. in) ove norml which proly negted ny irrigtion tretment effects. Other reserch showed reduced effects of irrigtion on cnopy growth (7) or yield (3) in the wetter yer of multiple yer study. Following the Novemer 4 plnting, rinfll ws elow verge for the weeks when irrigtion ws supplied; however, rinfll ws ove verge for pproximtely the next 6 weeks (Fig. ) which my hve similrly negted ny irrigtion tretment effects when shrus were mesured t 6, 34, or 5 WAP. Altogether, 8 mm (7. in) rinfll occurred ove norml during the 6 weeks fter irrigtion ws discontinued. The different volumes nd frequencies of irrigtion pplied to the root ll nd to the smll re round the root ll did not pper to hve gretly influenced cnopy growth or helth of #3 continer grown shrus in lndscpe soil under verge or ove verge rinfll conditions. Irrigting every 4 dys with 3 liters ppers to efficiently estlish shrus of this size when verge rinfll occurs fter plnting. Viurnum root systems were not influenced y irrigtion tretment t ny time. Only Ilex root spred nd root spred to cnopy spred rtio were influenced y irrigtion tretment. Ilex root spred rdius 6 nd 5 WAP (Fig. 3A) nd root spred to cnopy spred rtio 5 WAP (Fig. 3B) were greter when shrus received 3 or 9 liters irrigtion compred to 6 liters irrigtion in the My plnted plot. Root spred rdius ws not different mong min effect tretments for shrus plnted in Novemer, ut the interction etween irrigtion frequency nd volume ffected Ilex root spred to cnopy spred rtio (P =.4) (Fig. 4). Ilex irrigted every 4 dys produced the lest root spred to cnopy spred rtio when supplied with 9 liters compred to 3 liters (34, 5 WAP) or 6 liters (6 WAP). In greement with Gilmn et l. (7) this suggests tht pplying excessive irrigtion volume (in this cse 9 liters) reduced root spred to cnopy spred rtio for this drought tolernt species, nd could increse the time needed for plnts to grow enough roots to survive without irrigtion..5 Fig.. Significnt min effects nd interctions on cnopy growth of Viurnum (A, C) nd Ilex (B). Letters denote significnt differences (P <.5) etween irrigtion frequencies (A), volumes (C) or mong irrigtion volumes within frequency nd week fter plnting (B) t 6, 34, or 5 weeks fter plnting in My (A) or Novemer (B, C). Cnopy growth nd plnt qulity dt comined with pst reserch suggest tht estlishment of these shru species my e more influenced y environmentl conditions such s rinfll thn y the irrigtion frequencies nd volumes used in this test. Rinfll ws elow verge for the first 4 WAP in My 4 while plnts were eing irrigted; rinfll ws 6 34 5 Weeks After Plnting Rinfll (mm) 45 4 35 3 5 5 5 June 4 July 4 Hurricne Jenne Aug 4 Sept 4 Oct 4 Nov 4 Dec 4 Jn 5 Fe 5 Mr 5 Apr 5 My 5 Month - Yer Rinfll (mm) Historicl Averge Rinfll (mm) Supplementl Irrigtion Applied June 5 July 5 Aug 5 Sept 5 Oct 5 Nov 5 Dec 5 Jn 6 Fig.. Actul monthly rinfll June 4 through Jnury 6 nd historicl verge monthly rinfll. Arrows ( ) indicte plnting dtes ( = My 7, 4; = Novemer 6, 4). Spring-plnted Shrus Instlled Fll-plnted Shrus Instlled 5 J. Environ. Hort. 7(3):49 54. Septemer 9
Root Spred Rdius (cm) 9 8 7 6 5 4 3 A Root Spred to Cnopy Spred Rtio.5.5.5 6 34 5 Weeks After Plnting every dys + 6 WAP every dys every dys + 5 WAP every 4 dys + 6 WAP every 4 dys Irrigtion Frequency + Weeks After Plnting every 4 dys + 5 WAP Root Spred to Cnopy Spred Rtio.5.5.5 Fig. 3. B 6 34 5 Weeks After Plnting Others report reduced root growth with incresing irrigtion during estlishment. For exmple, incresed irrigtion frequency in winter plnted Photini frseri decresed growth; however, neither incresed frequency of irrigtion (every 3.5 or 7 dys) nor incresed volume (5, 75, or % replcement of ctul wter use) significntly ffected growth of summer instlled plnts (9). Our study found only slight influences in shru growth from irrigtion frequency nd volume regrdless of the time of yer when dt ws collected. Although seson of plnting could not e compred in our study, it seems tht under conditions of regulr rinfll, Viurnum, Pittosporum, nd Ilex shrus were mostly estlished y out 9 WAP with 3 liters wter supplied every 4 dys. This is indicted y the similrity of xylem wter potentil etween test plnts of ll tretments nd estlished indictor plnts (dt not shown). However, significnt nd frequent rinfll occurred during much of the study. When the first prolonged dry period without rinfll for 33 dys occurred fter irrigtion ws discontinued on the My plnted shrus, single irrigtion ppliction (in Novemer 4, Fig. ) ws needed to reduce wter stress evidenced y wilting leves or shoots on the shrus. Indictor plnts instlled 7 months prior to test plnts were not irrigted ecuse they did not exhiit stress symptoms. This J. Environ. Hort. 7(3):49 54. Septemer 9 Effects of irrigtion volume on root spred rdius (A) nd root spred to cnopy spred rtio (B) of Ilex 6, 34, or 5 weeks fter plnting in My. Mens for ech week with different letters re significntly different (P <.5). Fig. 4. Root spred to cnopy spred rtio for Ilex plnted in Novemer nd mintined with two frequencies nd three volumes of irrigtion. Mens within n irrigtion frequency for ech time (WAP) with different letters re significntly different (P >.5). would indicte tht test shrus were not fully estlished nd were not le to sustin themselves on rinfll lone, even 6 months fter plnting. It is possile then tht during significnt periods of dry wether the first yer fter plnting shrus my require occsionl irrigtion to mintin fvorle wter sttus. Irrigtion frequency ffected shru growth during estlishment when similr study ws conducted on the sme three species under rin shelter (4). Viurnum receiving 3 liters irrigtion every 7 dys hd only 5% survivl. Additionlly, Pittosporum nd Viurnum hd greter growth (lef re, shoot dry weight, totl iomss) when irrigted every dys compred with every 4 or 7 dys. Since our dt showed little difference in plnt response etween every nd 4 dy irrigtion frequencies in the outdoor environment, rinfll ppers very importnt in helping #3 continer-grown shrus during the estlishment period. However, growth nd survivl of Ilex cornut Burfordii Nn under rin shelter were not ffected y irrigtion frequency, indicting very high drought tolernce (4). Other reserch under rin shelter showed tht Ilex cornut Burfordii Nn could survive during the estlishment period when receiving irrigtion once every 4 dys for 3 weeks fter plnting (7). While irrigtion did not generlly influence growth in our study under norml or greter rinfll, Scheier et l. (4) suggest more frequent irrigtion my e necessry to estlish #3 continer grown shrus under drier conditions. Perhps smll woody plnts instlled in the lndscpe from continers do not respond with incresed growth from irrigtion () ecuse there re mny roots on the outside surfce of the continer root ll compred to the mount inside the root ll (); wheres on woody plnts in lrger continers (, 6) there is lesser mount of roots on the outside surfce of the ll compred to wht is inside. A lrge percentge of the totl-plnt root length on the outside surfce of the root ll my offer smll plnts n dvntge in estlishing quicker (8). This might explin why smll plnts my not respond to irrigtion provided there is some rinfll in the months fter plnting to moisten the root ll nd surrounding soil. The lrger plnts remin stressed longer ecuse there is lrge portion of the root system 53
still present in the originl sustrte even three yers fter plnting (5). Gilmn et l. (7) showed tht root contct with lndscpe soil on recently plnted continers is vitl to mnging post-plnting stress, nd this contct is ttriuted to the roots present on the outer periphery of the root ll. As roots on the outer surfce of the root ll tht re in intimte contct with lndscpe soil grow into the soil under the mulch, they hve ccess to mple moisture ecuse in mny new lndscpes there re few other living plnts with ctive roots in this soil. Mulch lso reduces the evportion tht would occur with re soil (8, 9), nd this keeps soil moist following rinfll or irrigtion. Literture Cited. Arnold, M.A. nd D.K. Struve. 993. Root distriution nd minerl uptke of corse-rooted trees grown in cupric hydroxide-treted continers. HortScience 8:988 99.. Blok, C.A. nd R.S. Hilire.. Drought responses mong seven southwestern lndscpe tree tx. J. Amer. Soc. Hort. Sci. 7: 8. 3. Brnett, D. 986. Root growth nd wter use y newly trnsplnted woody lndscpe plnts. The Pulic Grden :3 5. 4. Gilmn, E.F., J. Grosky, A. Stodol, nd M.D. Mrshll. 3. Irrigtion nd continer type impct red mple 5 yers fter lndscpe plnting. J. Aroriculture 9:3 36. 5. Gilmn, E.F. nd M.E. Kne. 99. Growth dynmics following plnting of cultivrs of Juniperus chinensis. J. Amer. Soc. Hort Sci. 6:637 64. 6. Gilmn, E.F., R.J. Blck nd B. Dehgn. 998. Irrigtion volume nd frequency nd tree size ffect estlishment rte. J. Aroriculture 4: 9. 7. Gilmn, E.F., T.H. Yeger nd D. Weigle. 996. Fertilizer, irrigtion nd root ll slicing ffect Burford holly growth fter trnsplnting. J. Environ. Hort. 4:5. 8. Iles, J.K. nd M.S. Dosmnn. 999. Effect of orgnic nd minerl mulches on soil properties nd growth of Firview Flme red mple trees. J. Aroriculture 5:63 67. 9. Krus, H.T. 998. Effects of mulch on soil moisture nd growth of desert willow. HortTechnology 8:588 59.. Mrshll, M.D. nd E.F. Gilmn. 998. Effects of nursery continer type on root growth nd lndscpe estlishment of Acer rurum L. J. Environ. Hort. 6:55 59.. Pine, T.D., C.C. Hnlon, D.R. Pittenger, D.M. Ferrin, nd M.K. Mlinoski. 99. Consequences of wter nd nitrogen mngement on growth nd esthetic qulity of drought-tolernt woody lndscpe plnts. J. Environ. Hort. :94 99.. Renquist, R. 987. Evpotrnspirtion clcultions for young pech trees nd growth responses to irrigtion mount nd frequency. HortScience : 3. 3. Rzeknowski, C. nd S.T. Roliecki.. The influence of drip irrigtion on yields of some cultivrs of pple trees in centrl Polnd under different rinfll conditions during the vegettion seson. Act Horticulture 537:99 936. 4. Scheier, S.M., E.F. Gilmn, M. Pz, nd K.A. Moore. 7. Irrigtion ffects lndscpe estlishment of Burford holly, pittosporum, nd sweet viurnum. HortScience 4:344 348. 5. Shckel, K.A., H. Ahmdi, W. Bisi, R. Buchner, D. Goldhmer, S. Gurusinghe, J. Hsey, D. Kester, B. Krueger, B. Lmpinen, G. McGourty, W. Micke, E. Mitchm, B. Olson, K. Pelletru, H. Philips, D. Rmos, L. Schwnkl, S. Siett, R. Snyder, S. Southwick, M. Stevenson, M. Thorpe, S. Weinum, nd J. Yeger. 997. Plnt wter sttus s n index of irrigtion need in deciduous fruit trees. HortTechnology 7:3 9. 6. Stler, L.B. nd C.A. Mrtin.. Irrigtion regimens differently ffect growth nd wter use efficiency of two southwest lndscpe plnts. J. Environ. Hort. 8:66 7. 7. Stpe, J.L., D. Bonkley, nd M.G. Ryn. 8. Production nd cron lloction in clonl Euclpytus plnttion with wter nd nutrient mnipultions. For. Ecol. Mng. 55:9 93. 8. Wtson, T.W. 5. Influence of tree size on trnsplnt estlishment nd growth. HortTechnology 5:8. 9. Welsh, D.F., J.M. Zjicek, nd C.G. Lyons, Jr. 99. Effect of sesons nd irrigtion regimes on plnt growth nd wter-use of continer-grown Photini frseri. J. Environ. Hort. 9:79 8.. Witherspoon, W.R. nd G.P. Lumis. 986. Root regenertion of Tili cordt cultivrs fter trnsplnting in response to root exposure nd soil moisture levels. J. Aroriculture :65 68. 54 J. Environ. Hort. 7(3):49 54. Septemer 9