Now, with the use of polyethylene film, airlayering is a method which every home ownercan use to increase his plants. The propertiesof this film are such that it is indispensable formany horticultural purposes. Although it allowsample gaseous exchange, it does not permit thefree transmission of water or water vapor, whichis the reason why it has so many uses in keepingplant materials alive.

The making of the air layer itself is verysimple. A longitudinal cut of about 2 in. is madeon the young twig, the cut going nearly to thecenter of the twig. (An adaptation of this is toremove a complete circle of bark 4 in. widearound the stem.) Then both cut surfaces aredusted with some hormone rooting powderwhich may (or may not) aid in the rooting.Hormodin #3 has been used, but undoubtedlyother materials are just as good. Moist sphag-num moss—about a handful—is packedbetween the cut surfaces and then all aroundthe entire cut, fully covering it, then tied in place.Polyethylene film is wrapped carefully andtightly about it, then tied top and bottom.Rubber bands used in grafting have notproved satisfactory for tying, but ScotchElectrical Tape # 33 has proved most satis-factory.

The wrapping and tying of the film should be done in such a way that the moss is wellcontained and that no opening in the film is leftfor the evaporation of the moisture from themoss.

The overlap of the film wrapping should beon the underside of the air layer so that rain-water will not seep in. Also, in taping the topend of the wrap, the tape should be started onthe bare twig and gradually spiral down tocompletely close the top end of the wrap inorder that rainwater will not seep down thetwig and into the moss inside. Many air layersmay have failed to root because this was notdone, since water seeping into the moss packingwill push out much of the air and create a soggycondition decidedly unfavorable to rooting. Ifproperly done, the air layer will remain moistfor months (some remain moist for a year) androoting may take place in a few months’ time.This is all there is to the operation. The timeof year when it is done, the size of twig used,the amount of hormone powder, the amount ofmoisture in the moss and the rooting tendenciesof the species used are variables with which oneworks to achieve proper rooting. Air layersmay be made in early spring on wood that isdormant, and again in June and July on twigsthat grew during the current year. Many plantsare propagated from both “hardwood” ordormant cuttings and “softwood” cuttingsmade of wood grown the current year; othersmay root better from just one of these types ofcuttings. Consequently one would expect thatthe time when these layers are applied with bestresults might well vary with the species.

Twigs have been rooted that were ftc. india., although usually one might expectnormal rooting from the twigs about the size ofa lead pencil. Because so very little moisturepasses through the film, one should be extremely careful not to have too much moisturein the sphagnum moss at the time it is appliedabout the cut. The moss should be squeezedprior to application so that it will be moist—notwet.

Certain plants, such as forsythias, privets,dogwoods and yew, root easily and for theseair layering is one method which can be used.In addition, certain of the plants which are hardto root respond to this teethed. Some years agoexperiments in rooting plants by air layeringwere carried out at the Arnold Arboretum.These experiments showed that in many casesair layering, applied early in the spring to plantsgrowing out-of-doors, is an excellent andversatile method of plant propagation whichmay be used by persons who do not haveproper greenhouse facilities for the more com-mon methods of grafting or budding indoors.It must be admitted, however, that an equalnumber of plants used in the experiments failedto root. Hence the process apparently cannotbe applied with t00% success to all woodyplants. Also, the matter of cutting off therooted layer and establishing it in soil as anindependent plant is not always a successfuloperation. Many times roots are formed by theair layer process, but when the layered branchis cut from the parent plant the roots fail tobecome established in the soil and the youngplant dies. To overcome this, the severingoperation might be done over a period of time,or soil might be packed around the rootedlayer, delaying the cutting from the parent plantuntil after the feeding roots have permeated thesoil.

In any event, air layering is a simple andpractical process, offering to the interestedgardener a means by which he can asexuallypropagate a few woody plants without the useof a hot bed or greenhouse.

Some plants which rooted successfully by theair layer method are:

1. Abeliophyllum distichum
2. Acer barbinerveA. capilipes
3. A. circinatumA. cissifoliumA. durettii
4. A. ginnala
5. A. griscum
6. A. palmatum dissectum
7. A. pensylvanicumA. platanoidesA. platanoides ‘Globosum’
8. A. saccharum ‘Temple’s Upright’
9. Aesculus carnea
10. A. hippocastanum
11. A.hippocastanum ‘Umbraculifera.Albizia julibrissin roscaBetula aurata
12. B.fontinalis
13. Carya tomentosa
14. Castanea mollissimaCatalpa bignonioides
15. C. bungei
16. C. speciosa
17. Cercis chinensis
18. Cladrastis platycarpaClethra barbinervis
19. Corylopsis glabrescens
20. C. spicata
21. Corylus chinensis
22. Cotinus coggygria pat peacesCotoneaster foveolata
23. C. horizontalis
24. Crataegus monogyna ‘Stricta’
25. C. pinnatifida majorCytisus praecox
26. Davidia involucrata vilmoriniiDiospyros lotus
27. Enkianthus campanulatusFranklinia alatamahaGinkgo biloba
28. Halesia carolina
29. H.monticola rosea
30. Hibiscus syriacus
31. Hippophae rhamnoidesIlex crenata convexa
32. I.ambigua montana ‘Macropoda’
33. I. gJabra
34. L verticillata
35. Indigofcra amblyanthaKoelreuteria paniculataLaburnum anagyroides
36. L.watereri
37. Lonicera maackii
38. Maackia amurensis
39. Magnolia heptapeta (denudata)
40. M.soulangiana ‘Alexandrina’
41. Males astracanica
42. M. atrosanguinea
43. M. `Dorothea’
44. M. floribunda
45. M. halliana spontanea
46. M. ‘McIntosh’
47. M. micromalus
48. M. prunifolia rinkii
49. M. purpurea
50. M. sargentii ‘Rosea’
51. M. spectabilis
52. M. sublobata
53. M. ‘Wabiskaw’
54. Metes alba ‘Pendula’Orixa japonica
55. Populus alba nivea
56. Prunus juddii
57. P. maackii
58. P. serrulata Amanogawa’
59. P. serrulata ‘Gyoiko’
60. P. serrulata ‘Kwanzan’
61. P. yedoensis ‘Taizanfukun’
62. Ptelea trifoliata aurea
63. Rhododendron ‘Dr. Charles Baumann’
64. R.’Josephine Klinger’
65. Styrax japonica
66. Symplocos paniculata
67. Syringa reticulata
68. S.prestoniae `Lucetta’
69. S. prestoniae ‘Paulina’
70. S. villosa
71. S.vulgaris vars.
72. Tamarix ramosissima
73. Tilia cordata
74. T.platyphyllos ‘Fastigia.’
75. Tsuga canadensis
76. Ulmus carpinifolia `Koopmannii’
77. U. carpinifolia `Sarniensis’
78. U.glabra
79. Vaccinium corymbosum ‘Jersey’
80. Viburnum carlesii
81. V.dilatatum
82. V. juddii
83. V. opulus
84. V. rhytidophyllum
85. V. rufidulum
86. V. sargentii
87. V. sargentii flavum
88. V. setigerum aurantiacum
89. V.sieboldiiWisteria floribunda Tongissima Alba’
90. W.floribunda ‘Naga Noda’
91. W. floribunda Niolacea-plena’
92. W. formosa
93. W. macrostachya
94. W. sinensis
95. W. venustaZelkova serrata
96. Z. sinica

Air Layering:

1. Make longitudinal cut and insert smallamount of slightly moist sphagnum moss.

2. Dust with hormone rooting powder.

3.Pack thoroughly with moist moss.

4.Cover and ho tightly, using polyethylenefilm.

5. Sever When thoroughly rooted.

There are a types ofgarden centers in America. The term is used bysome commercial nurserymen, seedsmen andflorists to denote a store or center where every-thing for the garden is placed on display forsale—seeds, plants, tools, machines and all themany types of things used by gardeners inmaking and caring for their gardens. These arepopular because potential buyers can see ondisplay the many things that they can use and These are proving popular for growers whowish to diversify their goods, and also togardeners who can find what they desire in oneplace without having to visit stores or sales-rooms which specialize only in one product. Thenumber of these garden centers is increasingannually.

The second type of garden center is one inwhich an organization or group of people havecombined to make available rooms for meetings,a library, and a permanent staff for givinginformation on gardening. Here are frequentlyoffered a series of lectures on various phases ofhorticultural techniques. This type of gardencenter is often financed by memberships, by”white elephant” sales and by the sale of booksand other things. Two outstanding examplesare The Garden Center of Greater Cleveland,East Boulevard at Euclid Ave., Cleveland, Ohio44106, and the Berkshire Garden Center, Inc.,Stockbridge, Mass., where many good orn-amental plantings are on the grounds for thepurpose of demonstrating actual living plantsand arrangements of them in living plantings.Such garden centers, with permanent staff, aredoing excellent work in disseminating horti-cultural information and are well worth theprice of membership.

In the first place, a scion and stock must be”compatible,” that is, they must be of a typethat will grow together, make a firm union andcontinue to grow afterwards. This is found outby experience, and the art of grafting is cen-turies old. One should not expect a scion ofMagnolia soulangiana to grow on apple or elmunderstock. In fact, it may not grow on all kindsof magnolia seedlings, but experience has shownthat it may be expected to grow best on under-stock of M. kobus or M. tripetala. Sometimesseveral species in the same genus are equallygood as understock, sometimes it has been foundit has been found that under certain conditionsone is better than another. English growers findthat Prunus serrula is easily compatible with P.avium understock, while some Americangrowers have better success with P. sargentiiunderstock.

In the grafting operation the theory is to placethe living cambium tissue of scion and under-stock in contact with each other. This is simply

done by making the proper kind of cut into theunderstock and gently slipping the whittledscion into it. This operation must be done whenboth scion and understock are about ready foractive growth. Actually, it is a greenhouseoperation where the understock, in a pot, hasalready been forced into active growth and thescion is yet dormant. Usually Feb. or March isgrafting time indoors.

As soon as the scion and stock arc slippedtogethcr, they are bound tightly in place toprevent movement between them. Flat rubberbands are specially made for this and are idealsince they can be bound just tight enough tohold the a together, but loose enough to thatthe rubber will give a little as the new graftincreases in circumference. This “tie” remains_on for a few months until stock and scion haveclosely knit, when it is simply cut and left onthe union to eventually fall off.

Grafting is also done out of doors at a timejust before vigorous growth commences on theunderstock. This is usually confined to treesthat are being “made over” as will be explainedbelow. Grafting small plants out of doors doesnot result in as much success as doing it insideunder controlled temperature and moistureconditions.

Factors other than timing must be right. Airtemperature must be in the 70’s or conduciveto continued plant growth. Moisture must bepr.ent‚Äîthe graft union mast not bc allowed todry out in any way. Disease spores must notget into the union. These are the reasons whygrafting is usually carried out in the greenhousein “grafting cases,” places enclosed by glass orpolyethylene with high humidity. This is alsothe reason why the graft union is covered withwax or polyethylene film as soon as it is madeto keep the tender new-forming cells fromexposure and possible drying out.

The most difficult time for the new graft iswhen it is noted that the scion has started intoactive growth. It must be kept in active growth,yet too high a temperature and too muchmoisture in the grafting case may cause it togrow too rapidly and fail to make a properunion. Here experience certainly aids theindividual in properly regulating moisture andtemperature.

The most important decision to make ingrafting is to select the right kind of graft cutto make. Actually, if properly done, any oneof the methods should result in a successfulgraft, but experience has shown that certaintypes of grafting cuts seem to result in better endr.ults on certain species than ashore. This isnot the place to go into this detailed discussion,but one should be familiar with the differenttypes.

Whip Graft

A double matching cut is made in both stockand scion. If this is to be used, the understockand the scion should be about the same dia.(lead-pencil size or slightly larger) and the topof the stock should be completely cut off aninch or so above the place of the proposedunion. The whip graft is also ideal to use in rootgrafting, that is, in grafting a scion on to a pieceof root (of the same dia.). If done properly, andit takes experience to make just the right cuts,it can be highly successful because there is somuch of the cambium that can be fitted togetherin this double cut.

Side Graft

Merely making a slanting cut into the stock

and inserting a wedge-shapcd scion into it. Thisis often the method chosen when thc stock islarger in dia. than the scion. Sometimes the topof the stock is severed just above the graft assoon as it is made. Other times it is left to growfor a week or two and then cut off. It is thismethod which is frequently used in bonsaiculture to supply a new branch at exactly theright place it is needed.

Cleft Graft

This is the type of graft employed in graftingtrees in the open. It is frequently employed ingrafting apples, where a tree of an old out-moded variety is to be “changed over” to a newand better variety. In this case, all the mainlimbs are sawed off carefully and “clefts” or splits are made in them with a large graftingtool similar to a butcher’s knifc. Two or 3 suchopenings can be made in a 4-6 in. branch. Then,3 or more wedge-shaped scions are insertedcarefully, so the cambium tissue of stock andscion meet exactly, the entire union is paintedwith wax and one then awaits developments.Only of the 3 or 4 scions will be allowed togrow eventually, but it is a quick method ofmaking over a tree of bearing size. In fact, thenewly made-over tree may grow so well that itmay begin producing the new variety of applein 3 or 4 years. Because the stock is so large, itis not necessary to tie stock and scion togetherin such a graft, for the properties inherent inthe wood of the large branches are enough tohold the scions tightly for all practical purposes.

Bark Graft

This is done on the cut limbs of trees, merelyby slitting the bark a few inchos in a straightline from the cut surface, and then inserting thewedge-shaped scion just between the bark andwood of the stock. Three or 4 of these can beinserted, but the whole should be tied tightly toprevent the bark of the branch from curlingaway or splitting farther and thus exposing thescion to drying out.

Approach GraftingConsider z small plants in pots, one of a veryrare type, the other a worthless seedling. The

seedling would act as the undcrstock for therare plant, the whole idea being that one doesnot risk loss of the rare plant in this method. Acut is made in the side of the understock or someof thc bark is very carefully removed just to thecambium. A matching cut is made in the rareplant or a matching part of its bark is carefullyremoved. Then they are joined together, tied andpainted, while the tops of both are allowed togrow. If it is obvious that the union is growingtogether, the part of the undcrstock above thegraft can be removed. When the union issolidly made, the scion material can be partiallycut away from the scion plant, and later anotherdeeper cut made so that the severance of thescion from the parent plant takes place over aperiod of weeks. This is a method used by theexperts to graft two plants together that areotherwise difficult.

lnarching

Sometimeo a plant is growing with the wrongkind of understock and the tree needs a betterroot system. Young plants arc established at thebase, a narrow strip of bark removed on the1000 10 correspond with a similar width of barkremoved on the new plants. Several such plantscan be stabilized and grafted 00 000 trunk.

Bridge GraftingFrequently used in the case of a tree that hasbeen completely girdled by rodents or byaccident. The bark of the tree is cleaned off to smooth straight lines, several twigs of the propersize and length are cut from the tree itself andinserted under the bark of the tree in the samemanner as any bark graft, above and below itspart with injured bark. The bridge grafts can benailed or tied in place and the whole exposedwound painted with wax. The idea here is to cutthe top and bottom of the scions in such a waythat they can be inserted underneath the barkabove and below the wound, with the cambiumtissues of stock and scion in contact with eachother. Hence those shoots will, if they grow, actas bridges over the injured trunk for the upwardand downward flow of nutrients and foods.Many a damaged tree has been saved in thisway. However, such an operation is bast donewhen the tree is dormant, certainly not whenthe scions are in leaf. If properly done, thesescions will gradually increase in size and maycompletely heal over the injured trunk bygrowing solidly together.

Double GraftingSometimes this method is used, especially toproduce a dwarf plant or when one kind ofplant material is not compatible with the under-stock. Grafting is done in the normal way usingan “intermediate” scion, that is, a scion from aplant that will be compatible with the under-stock and the plant to be grafted as well. An example is the grafting of Bartlett Pear onquince roots for dwarfing. These 2 are notcompatible but if a seedling pear is grafted onthe quince roots, then the Bartlett Pear graftedon the seedling pear, this results in a good tree.This can be done in different ways. The BartlettPear can be grafted on pieces of the seedlingpear and the grafted pieces put in moistenedpeat moss in a cool place fore few weeks untilcallused, when this piece (with scion and inter-mediate graft) is grafted onto a dormant quinceroot. Or, the seedling pear can be budded onto toted cuttings of the quince one summer,then the Bartlett Pear can be budded on theseedling pear the next.

So, grafting can be a complicated processbut, if done properly, results in fairly good trees.Sometimes, years after the grafting, one noticesa large hump at the graft union, showing clearlythat the stock has grown much faster than thescion. Sometimes just the reverse is true.Frequently this is not serious but, wheneverpossible, it is always best to select an understockthat grows at the same rate as the plant fromwhich the scion was taken