Intergeneric Graft Compatibility Within the Family Araliaceae

RESEARCH UPDATES

Fatshedera ( Fatsia x Hedera) that have Materials and methods Intergeneric been grown erect are sold as novelty specimens. Growers usually get a high Twenty-three cultivars of Graft percentage of successful grafts with Araliaceae representing six genera and Compatibility healthy plant material and good graft- 16 species were obtained from com- ing technique. mercial sources. Two species each of within the Family Variegated forms of Aralia elata two genera native to Hawaii, do not root from cuttings and produce Cheirodendron and Tetraplasandra, Araliaceae nonvariegated seedlings. The varie- were collected in the Koolau Moun- gated forms are propagated by bud- tains on Oahu (Table 1). ding onto seedling or vegetatively Rootstocks propagated from tip Kenneth W. Leonhardt1 produced nonvariegated rootstocks of cuttings rooted in equal parts ver- A. elata (Leiss, 1977). One variegated miculite and perlite under intermit- form of A. elata also has been cleft- tent mist and full sun were grown in Additional index words. Aralia, grafted successfully onto a rootstock 15-cm plastic pots containing equal Ginsing, Panax family, propagation of A. spinosa (Raulston, 1985.) parts peat moss, perlite, and field soil The relative ease of the Hedera x (by volume). Lime and a slow-release Summary. Novelty Araliaceae potted Fatshedera graft raised the possibility granular fertilizer were incorporated. plants were created by a wide variety of graft compatibility of Hedera with Rootstocks were established in a green- of interspecific and intergeneric graft other relatives, particularly those grow- house under 25% shade cover until combinations. Twenty-four species of ing tall rapidly or having other desir- grafted. 10 genera were tested, of which 20 able characteristics. Preliminary A wide assortment of rootstock– species of eight genera resulted in 85 graft combinations that grew. attempts to graft Hedera onto Polyscias scion combinations were tested for Intergeneric graft combinations with and Schefflera were promising. Our interspecific and intergeneric compat- Schefflera arboricola included eight study was undertaken to determine ibility. One-hundred and one test com- species in five other genera. Interge- graft compatibility between other spe- binations and seven control neric graft combinations with cies and genera in the Araliaceae and to combinations were tested. Twelve cul- x Fatshedera lizei included 11 species determine if scion growth was affected tivars (five genera, nine species) were in five other genera. Schefflera by the choice of rootstock. used as rootstocks and 22 cultivars (six arboricola scions grew more vigor- ously on Nothopanax and Polyscias rootstocks than on Schefflera root- Table 1. Araliacea cultivars used in graft compatibility studies. stocks. The highest intergeneric graft compatibility scores for each genera Used as: included combinations with Schefflera. Genus species Variety or cultivar Rootstock Scion Plant propagation instructors may find these results useful in designing Cheirodendron sp. a X grafting exercises. bX x Fatshedera lizeiz XX Hedera helix Hahn’s X Nothopanax scuttelarius X he Araliaceae is an important Polyscias balfouriana marginata X plant family in the commercial P. balfouriana Pennockiiz XX foliage plant industry. Species P. filicifoliaz XX T z and cultivars of Aralia, x Fatshedera, P. filicifolia Golden Prince XX Fatsia, Hedera, Panax, Polyscias, P. fruticosa Elegans X Pseudopanax, Schefflera, and P. guilfoylei Crispaz XX Tupidanthus are popular decorative Quinquefolia X plants for interior use. Plants com- Variegata X monly known in the trade as Brassaia P. guilfoylei victoriae X actinophylla and Dizygotheca elegantissima Variegata X have been reclassified into Schefflera P. paniculata Variegata X but retain the same species epithet Schefflera actinophylla X S. arboricolaz XX (Lowry et al. 1989). Aralias are also z popular for landscapes in areas with S. arboricola Variegata XX mild winters. “Ivy Trees” made by S. elegantissima X grafting cultivars of Hedera helix onto S. polybotrya X S. sp. Big Leaf X rootstocks of the intergeneric hybrid x Manila Ruffle X Star Shine X 1Department of Horticulture, University of Hawaii, Tetraplasandra kauaiensis X 3190 Maile Way, Honolulu, Hawaii 96822. T. meiandra X The cost of publishing this paper was defrayed in part by Tupidanthus calyptratus X the payment of page charges. Under postal regulations, this paper must be hereby marked advertisement solely to zCultivars used as scions grafted onto the same cultivar to serve as controls for the benchmark indicate this Fact. compatibility rating of 4 = vigorous scion growth.

254 HortTechnology ● July/Sept. 1996 6(3) Fig. 1. Mean scored for rootstock–scion compatibility for selected Araliaceae. Scores for control combinations are underlined genera, 16 species) were selected as failure of scion to 5 = very vigorous Table 2. Mean graft compatibility scores scions (Table 1). Side veneer grafts scion growth) was used to assess graft for Polyscias and Schefflera scions on four rootstock genra. The number of different were used for Hedera because of the combination compatibility. Seven cul- test combinations is in parentheses. small diameter of the scions. Cleft tivars of three genera were used as grafts were used when scions were scions on their own rootstocks as a Stocks/scions Polyscias Schefflera much smaller in diameter than stocks. control. Their compatibility rating of x Fatshedera 1.3 (3) 3.0 (4) Standard whip and tongue grafts were 4 denotes vigorous scion growth (Fig. Nothopanax 3.0 (4) 3.0 (6) used for all others (Hartmann et al., 1). Aesthetic appeal of combinations Polyscias 3.0 (17) 2.9 (8) 1990). Two to six replications were was not considered in evaluating com- Schefflera 1.5 (10) 2.4 (15) made of each graft combination. One patibility of rootstocks and scions. Mean 2.4 (34) 2.7 (33) or two small leaves or parts of leaves were retained on each scion. The graft Results and Discussion unions were wrapped with raffia and Eighty-five graft combinations, rootstock than S. polybotrya for Hedera, sealed with an asphalt-based grafting including all combinations, except Polyscias, and Schefflera scions. Four- compound. Grafted plants were placed those involving a native Cheirodendron teen species or cultivars were grafted under 73% shade for 2 to 4 weeks. or Tetraplasandra species, grew. on S. polybotrya, but only x Fatshedera When vegetative buds on the scions Nothopanax and Polyscias proved and two Schefflera species performed began to grow, plants were transferred to be suitable rootstocks for Polyscias acceptably. Grafts of four cultivars of to full sun. The raffia was cut after 6 and Schefflera scions. The hybrid ge- three Polyscias species on S. polybotrya weeks to avoid girdling. Suckers that nus x Fatshedera also was a suitable resulted in very stunted scion growth, appeared on the rootstocks were re- rootstocks for Schefflera scions, but but each Polyscias cultivar grew accept- moved. less suitable for Polyscias scions (Table ably when grafted onto S. arboricola, All replications of graft combina- 2). X Fatshedera also was a suitable Nothopanax, or other Polyscias root- tions were made on the same day and rootstock for Hedera, one of its paren- stocks (Fig. 1). were evaluated 6 months later. A rat- tal genera. Six reciprocal graft combinations ing system based on scion growth (0 = Schefflera arboricola was a better using three genera were made (Table

HortTechnology ● July/Sept. 1996 6(3) 255 RESEARCH UPDATES

Table 3. Performance of six reciprocal graft combinations.

Compatibility Compatibility score Stock Scion score of reciprocal graft P. balfouriana ‘Pennockii’ x F. lizei 32 P. filicifolia 33 P. guilfoylei ‘Crispa’ 3 3 P. filicifolia ‘Golden Prince’ P. guilfoylei ‘Crispa’ 3 3 S. arboricola ‘Variegata’ x F. lizei 33 S. arboricola 44

Table 4. Summary of highest intergeneric graft compatibility scores as either rootstocks , scion, or both.

Genus Highest score Most compatible genera Schefflera 5 Nothopanax, Polyscias Nothopanax 5 Schefflera Polyscias 5 Schefflera x Fatshedera 4 Nothopanax, Polyscias, Schefflera Hedera 3 x Fatshedera, Polyscias, Schefflera Tupidanthus 2 Schefflera Cheirodendron 0 None Tetraplasandra 0 None

3). There were no appreciable differ- These results indicate that a wide ences among reciprocal grafts of five of variety of intergeneric graft combina- the combinations, but the combina- tions are possible in the Araliaceae. tion of x Fatshedera lizei on Polyscias Table 4 lists the genera tested, the balfouriana ‘Pennockii’ resulted in a highest intergeneric graft compatibil- stronger union and better scion growth ity score achieved as either rootstock than the reciprocal combination. or scion, and the genera combined for Schefflera arboricola was unsur- that score. The highest intergeneric passed as a scion and gave vigorous to graft compatibility scores achieved for very vigorous growth when grafted on each genera included combinations its own variegated cultivar, x Fatshed- with Schefflera. era, Nothopanax, or Polyscias. It grew This information on graft com- less vigorously on S. polybotrya and patibility within some Araliaceae may Tupidanthus but was equal to or better be useful to nurserymen in creating than other scions tested on these two novelty potted plants for decorative rootstocks. When grafted onto use. The ready compatibility and ease Nothopanax and P. guilfoylei of grafting for many combinations also ‘Variegata’, Schefflera arboricola grew may be useful in designing grafting more vigorously than on its own roots. exercises for propagation classes. This was the only example of a control combination outperformed by a test combination (Fig. 1). Literature Cited Tupidanthus was a poor rootstock for Hedera, Polyscias and Schefflera. X Hartman, H.T., D.E. Kester, and F.T. Davies. 1990. Plant propagation pinciples Fatshedera on Tupidanthus also re- and practices. 5th ed. Prentice Hall, sulted in very stunted scion growth. Englewood Cliffs, N.J. All 16 combinations using four species of two Hawaiian native genera Leiss, J. 1977. Propagation of Aralia elata of Araliaceae on x Fatshedera, ‘Variegata’. Proc. Intl. Plant Prop. Soc. Nothopanax, Polyscias, and Schefflera 27:461–463. failed (Fig. 1). The environmental con- Lowry, P.P., J.S. Miller, and D.G. Frodin. ditions at a 2000-foot elevation where 1989. New combinations and name changes the Cheirodendron and Tetraplasandra for some cultivated tropical Old World and scions were collected was quite differ- Pacific Araliaceae. Baileya 23(1):5–13. ent from the near sea-level greenhouse Raulston, J.C. 1985. Ten outstanding flow- conditions in which they were tested ering trees for potential southeastern U.S. and may have contributed to the fail- Production. Proc. Intl. Plant Prop. Soc. ures. 35:723–728.

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