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Home and Garden Bulletin No. 80 U.S. DEPARTMENT OF AGRICULTURE CONTENTS

Page Layers 4 Simple layering 4 Air layering 5 Care after rooting 6 Cuttings 8 Rooting period 8 Care after rooting 9 Grafts 10 Bud grafts 10 Cleft grafts 11

Growth Through Agricultural Progress

Prepared by Crops Research Division, Agricultural Research Service

This bulletin supersedes Farmers' Bulletin 1567, "Propagation of Trees and Shrubs.'

Washington, D.C. Issued February 1962

For sale by the Superintendent of Documents,, U.S. Government Printing OflBce Washington 25, D.C. ' Price 10 cents ■v nuMt PROPAGATION

ORNAMENTAL TRÍES >

SHRUBS

Many kinds of ornamental trees, bud grafting. Or you can get large new flowering shrubs, roses, and evergreens plants soon after propagating by cleft are easy to propagate by home methods- grafting. Bud grafting and cleft grafting These home methods utili2;e inexpensive, demand more skill and specialised knowl- easily available materials and equipment. edge than the other methods of propa- Plants propagated by layers, cuttings, gation. or grafts have characteristics exactly For greatest success in propagating— the same as the parent plants. Plants • Use only healthy plants. propagated by seeds often have char- • Propagate in the proper season. acteristics different from those of their • Protect propagating material from parents. drying. Many ornamental trees and shrubs • Give newly propagated plants extra can be propagated by layering. Because care until they are well established in a branch of the parent plant is needed their permanent location. to form each new plant, this method is practical only for propagating a small number of plants. Many kinds of trees and shrubs can Plants Dijficult to be propagated from cuttings. One Propagate parent plant yields enough propagating material to start a large number of new Some ornamental trees and shrubs are plants. The new plants are small, difficult or impossible to propagate by however, and must be tended carefully layers or cuttings. Among these plants for several years. are fir, pine, hemlock, locust, redcedar, Some trees and shrubs can be propa- mimosa, redbud, ginkgo, mountain-laurel, gated by grafting. You can propagate goldenrain-tree, blue spruce, myrica, a large number of new plants from a and andromeda. small amount of propagating material by LAYERS soil. This is called simple layering. If the branch cannot be bent to the ground, If a branch of an ornamental plant is layer it by wrapping the wound with wounded and the wound is covered with moistened sphagnum moss. This is air a rooting medium—soil or sphagnum layering. moss—the branch usually will strike Simple Layering roots while it is still attached to the parent plant. It then can be severed Professional propagators use many vari- from the parent and set out as a new ations of the layering-in'soil method of plant. This method of propagation is propagation. The easiest for the home layering. It is successful with more propagator is simple layering—burying a species of trees and shrubs than is any single branch in the soil with only its other method of vegetative propagation. tip protruding. Layering usually is most successful if Before making a simple layer, work done in spring or in late summer; rooting leafinold or peat and sand into the soil is most vigorous in cool weather. where the branch will be layered. If a branch is low and sweeping and Begin the layering operation by can be bent to the ground easily, layer wounding the branch. Make a slanting it by burying the wounded part in cut 2 inches long on the upper side of

SIMPLE LAYERING Upper left: Wounding the branch. Lower left: Bending the tip of the branch upright. Right: Rooted branch cut free from parent plant. the branch about 12 inches from the This will give it time to recover from tip. Dust the cut with rooting stimu' the shock of being cut. Then transplant lant. it to a nursery bed, where it should be Then fasten the branch to the soil. tended carefriUy for a year. Pin it down between the trunk and the cut with a wooden peg or wire wicket, Air Layering or weight it with a stone. After the branch is pinned to the Kits containing all the materials soil, bend the tip upright. As you do needed for air layering are available at this, twist the branch as if you were garden-supply stores. If you do not turning a screwdriver one^half a turn. buy a kit, you will need the following: This will open the cut. • A sharp knife. Next, place a second peg or pin over • Rooting stimulant. the branch directly at the point of the • Sphagnum moss. cut. • Polythene plastic sheeting. Cover the pegged branch with several • Plastic electrical tape. inches of son into which leafinold or peat and sand have been worked. One-yearold branches are best for Mound the soil around the upturned air layering. Older branches may form stem so the wound is 3 or 4 inches roots, but take longer to do so than underground. Pack the covering soil branches that are 1 year old. firmly. Make the layer 12 to 18 inches from Mulch the soil over the layered branch the tip of the branch. If there are any with straw or leaves. Water frequently ; leaves within 6 inches of the point keep the covering soil moist. where the layer is to be made, remove When the layer has formed roots— them. the following spring for spring'layered Begin air layering by wounding the branches, or the seccmd spring for fall' branch. Make a shallow, slanting cut layered branches—cut the rooted branch about 2 inches long in the branch. Dust free from the parent plant. rooting stimulant into the cut and place Leave the new plant in place for 2 or 3 a small sliver of wood in the cut to keep weeks after it is severed from the parent. it open. Next, dampen a fist'siie ball of sphagnum moss and squee2;e it as tightly Rooting StirnulcCnts as possible to remove excess water. Wrap the sphagnum around the branch, Several organic chemicals stimulate covering the wound. the formation of roots on layers and Then, cover the ball of moss with cuttings. Preparations containing these plastic sheeting—^an 8^ by lOinch sheet chemicals are available from garden- is big enough. Wrap the plastic around supply stores. the moss-covered branch so the sheet Some brands of rooting stimulant are overlaps itself. sold in several strengths. Finally, twist the ends of the plastic Follow directions on the container sheeting around the branch and fasten label when using rooting stimulants. them securely with plastic electrical tape. BN-1895 Taping plastic sheeting around an air-layered branch to make a tight package.

Watch for collection of rain water in If roots have not formed by the third the plastic package. If water seeps in spring, remove the wrappings from the the ends of the package, punch a small branch. Neither the parent plant nor hole in the plastic to allow the water to the branch will be seriously harmed if drain out. the layer is unsuccessful. Try layering Leave the air layer undisturbed for another branch; you may be successful one full growing season. Branches this time, even though your first that are layered in the spring should attempt failed. root by the following spring. Branches layered in the fall should root by the second spring. When roots have formed, they usually are visible through the Care After Rooting plastic covering. In spring, after the roots have formed, The root systems of newly rooted remove the plastic and cut off the branch layers are small in relation to the tops. below the roots. Set the new plant in You can reduce loss of water through the the nursery bed. leaves of these new plants—and lessen SHADING A, Burlap screen attached to stakes; B, cylindrical screen of bamboo or reed matting; C , wire screening supported by corner stakes for shading a nursery bed.

danger of wilting and plant death—by made of snow fencing, lath, reed matting, pruning and shading. or burlap attached to wood framing. As soon as you plant new rooted After the first winter remove the layers in the nursery bed, prune all screens. The roots should be large side branches; remove one-third of their enough by the end of the season to original length. absorb all water needed by the plants. Erect screens around the new plants The plants then can be safely trans- to shade them. Suitable screens can be planted to their permanent location. CUTTINGS you get the mixture too wet, add dry -sand and peat to it. Cuttings, «■ slips, made of newly Fill the flower pot with this rooting formed wood are easiest to root. medium. Take cuttings from roses and spring' Now make the cuttings. Make a flowering shrubs in midsummer when slanting cut through the stem 2 to 6 the new stems are no longer succulent inches from the tip of the cutting. but have not yet become hard. Strip the leaves off the lower half of Cuttings of some evergreens—holly, each cutting and dip the base of the yew, arborvitae, and juniper—root best cutting in rooting stimulant. Insert the if they are taken from the plants in late cutting to about half its length in the fall or early winter, after they have rooting medium. been subjected to several heavy frosts. Put the cuttings close together; a Boxwood cuttings can be taken at any ó-inch flower pot will hold 10 or 12 season. cuttings. When the flower pot is full, One way to root the cuttings is in spray the cuttings hghtly with water. a flower pot that is kept covered with a Now place the flower pot inside a plastic bag. The plastic cover allows the polythene freezer bag. Twist the top cuttings to "breathe" but prevents loss of the bag closed and fasten it with a of water. rubber band. This forms a miniature For a rooting medium, use a mixture plastic greenhouse that is vapor procrf; (Â1 part clean sand and 1 part peat moss. the cuttings will need no more water Moisten the mixture. When the mixture until they are well rooted. has the proper amount of moisture, only Set the cuttings in a window where a drop or two of water will come from they are exposed to dayhght but never a handful that is squeezed tightly. If to direct sunlight. Heat frcxn direct sunlight may kill the cuttings.

Rooting Period

Cuttings of most plants will form roots within 2 months. Cuttings made in midsummer should be rooted by fall; those made in winter should be rooted by spring. After they have been in the flower pot for 2 months, very care- fully dig one of the cuttings and inspect it fcr rooting. If no roots are visible, replant the cutting, close the bag, and set the flower pot back in the window. Hold summer cuttings until spring, winter Flo'mrer pot full of cuttings encloeed in cuttings until early summer. Then a plastic freezer bag. The cuttings need not be watered again until after inspect them again for rooting. Con- they are -vfeW rooted. tinue periodic inspection during the 8 N-3««S Ne-w plants in a simple coldframe for protection daring their first -winter.

growing season—about once a month— Care After Rooting until the cuttings root or until they turn brown or black, indicating death After cuttings have rooted, grow of the cuttings. them in a coldfirame for one winter before planting them in their permanent loca- tion. Harden the plants for moving to the coldframe by opening the plastic Freeze Damage in bag far an hour or two each day. After Coldframe a week of this, the plants should be hardened enough to move safely. Heat from sunshine can warm the air If cuttings root in spring or early inside a sash' or plastic-covered cold- summer, transplant them immediately frame sufficiently to start growth in from the pot to an open coldframe. the new plants. If freezing weather In fall, cover the coldframe with sash follows, the plants may be killed by the or plastic sheeting. cold. If cuttings root in late summer or To prevent this freeze damage, keep fall, either transplant them immediately the plants cool and dormant. Place the from the pot to a closed coldframe, or coldframe in a shady location, or open place the entire pot of cuttings in the the coldframe slightly on sunny days coldframe and transplant in the spring. to ventilate it and dissipate the heat. If you decide to leave the cuttings in the pot, dig a hole in the sou of the coldframe and set the flower pot in the For stocks, use seedlings or rooted hole with its rim even with the soil cuttings. A good size of stock for surface. Fill in around the flower pot budding is 3/16 to 3/8 inch in diam- and firm the soil. eter—about the thickness of a pencil. In spring, after they have over- Cut bud sticks from the desired wintered in the coldframe, move the variety. The buds should be plump but plants to a nursery bed. Shade them dormant. Cut off the leaf about one- and water frequently during their fourth of an inch from the bud. The first season. The plants, except shade- piece of leaf stem that is left protects loving kinds, do not need shading or the bud and is useful as a handle for special watering after the first year. holding the bud. Transplant new trees and shrubs to Using a very sharp knife, make a their permanent locations after they T-shaped cut in the bark of the stock. grow 12 to 24 inches tall. Begin the stem of the T near the ground line and cut upward about 1 inch. Then make the crosscut at the top of the GRAFTS vertical cut. The crosscut should extend about one-third of the way around the For grafts to be successful, the trans- stock. When making the T, cut only ferred part—the scion—must be from through the bark, not into the wood. a plant that is closely related to the Use the point of your knife to lift rooted part—the stock. For example: the bark along both sides of the vertical Graft pink dogwood scion on white cut. dogwood stock, or graft hybrid tea Now cut the bud. Start the cut rose scion on multiflora rose stock. about one-fourth of an inch below the The growing tissues of the scion and bud. Cut under the bud only deep stock must be in close contact for the enough to take a thin sliver of wood. two parts to unite. This growing After the knife blade passes beneath the tissue—the cambium—is the soft layer bud, angle the cut upward and outward of cells between the bark and the wood. to remove the bud with a shield of Many types of grafts are used for bark about three-fourths of an inch long. the propagation of ornamental trees Insert the lower part of the bud shield and shrubs. The most useful types for into the T-cut. Then push it down so the home propagator are bud grafts and the cut surface of the shield is flat cleft grafts. against the wood of the stock. The bud shield should be completely Bud Grafts enclosed in the T-cut. If part of the shield protrudes from the top of the Bud grafts are useful for propagating T, cut it off. a large number of plants from a small amount of scion material; only one leaf After the bud is inserted, wrap the bud is needed to form each new plant. cut with a piece of rubber band or a Make bud grafts any time during the narrow strip of plastic sheeting. Take growing season when the bark of the three or four turns below the bud and stock will peel easily from the wood and again above the bud. Do not cover the dormant buds are available. bud with wrapping. 10 ^^Jñ

BUD GRAFTING A, Bud stick; B, T-shapcd cut in bark of the stock; C, bark raised along both sides of the cut; D, bud inserted; E, completed bud graft bound w^ith a rubber band to prevent drying.

Three to five weeks later, cut the scion wood is cleft grafted on heavy wrapping away; the bud should be branches of the stock plant. united with the stock in this time. Make cleft grafts while the stock and Buds usually remain dormant until scion plants are dormant. Late winter the next season. In early spring, cut is a good time for cleft grafting. OÍF the top of the stock plant at a point For scion wood, use material from about one-half inch above the bud. This the previous year's growth. For each will force the bud to sprout; all growth stock, cut two scions, each of which from the bud will be similar to the bud- includes three buds. Cut the scions source plant. about 1 inch below the lowest bud. To prepare the stock, saw it off squarely Cleft Grafts at the point where you wish the graft to be. With a broad chisel or a stout Large new plants can be propagated knife, split the end of the stock to a in a short time if scion wood is cleft depth of 2 or 3 inches. Place a wedge in grafted to the main stem of the stock the split to hold it open. plant. Or several varieties of a plant Now prepare the scions. With a can be grown on the same main stem if sharp knife, carefully trim the butt

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CLEFT GRAFTING A, Stock prepared for grafting; B, t-w^o wedge^haped scions prepared for each split stock; C, scions inserted in stock so cambium layers touch; D, cleft graft covered with a plastic freezer bag.

of each scion to the shape of a wedge. Protect the scion from drying; coat Begin the cuts on each side of the lowest all cut surfaces with grafting wax or bud. Make the wood on the bud side tree'coating compound—^both of which of the wedge a Httle thicker than the are available from garden^supply stores— wood on the opposite side. or cover the graft with a polythene bag Insert the scions in the split stock, tied around the stock. with the lowest bud to the outside. If you use a polythene bag, shade the The cambium layers of the stock and graft to protect it from overheating; scions should be in contact. If the direct sunshine can kill the scion. Leave scions are set in the stock at a sHght the bag on the graft until new growth angle, the cambium layers are more fills the bag—probably in late spring. likely to meet than if the scions are set Then remove the bag and cover all straight. cut surfaces with treccoating compound. When the scions are in place, remove At the end of the first growing season, the wedge from the stock. Pressure inspect the scions and cut ofi^ the weaker from the split stock should be sufficient of the two. Cover the stub of the weak- to hold the scions tightly. er scion with tree-coating compound.

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U.S. GOVERNMENT PTONTING OFFICE: 1962 O—614860