Asexual Plant Propagation This presentation is from Virginia Tech and it has not been edited by the Georgia Curriculum Office.

Plant Propagation The reproduction of new plants from seeds or vegetative parts of a plant. One of the most interesting and important areas of horticulture is plant propagation. All organisms, including plants, reproduce. Plant propagation is the term used to refer to the reproduction of new plants from seeds or vegetative parts of a plant.

Asexual Propagation The reproduction of new plants from the stems, leaves, or roots of a parent plant. No seeds are used, just portions of the parent plant which are placed in soil Asexual propagation is the reproduction of new plants from the stems, leaves, or roots of a parent plant. In this method of plant production no seeds are used – just portions of the parent plant which are placed in soil.

Benefits of Asexual Propagation Produce plants faster Disease free stock Works when seeds are hard to germinate Plants produced are genetically identical to the parent plant “Clones” Plants with or without reproductive parts can be produced Less Expensive in some cases The discovery of asexual propagation allows propagators to produce more plants faster, especially in cases when seeds are difficult to germinate or plants produce seeds that are not viable. The plants also are from disease free stock. You can not grantee that seeds are disease free. One of the most important benefits of asexual propagation is that the plants produced are genetically identical to the parent plant; therefore, they have the same traits as the parent plant. This type of plant is known as a clone. In some cases it can also be more economical to produce plants asexually rather than by seeds.

Where Can Cuttings be Taken From? Roots Stems Leaves The most common and often used method of asexual propagation is the use of cuttings. Cuttings are detached portions of the plant, such as stems, leaves, leaf-buds, or roots that form missing parts to grow into complete new plants.

Methods of Asexual Propagation Stem Cuttings Leaf Cuttings Leaf Bud Cuttings Root Cuttings Cuttings are classified as stem cuttings, leaf cuttings, leaf-bud cuttings and root cuttings.

Stem Cuttings Softwood Cuttings Herbaceous Cuttings Semi-hardwood Cuttings Hardwood Cuttings Conifer Cuttings See Figure 1 on handout Portions of the stem that contain terminal or lateral buds are used for stem cuttings. Stem cuttings are placed in growing medium in hopes that they will produce roots. The time of year, stage of growth, and type of stem are factors that will determine if the cuttings will produce roots. Stem cuttings are grouped as Softwood Cuttings Herbaceous Cuttings Semi-hardwood Cuttings Hardwood Cuttings Conifer Cuttings

Softwood Cuttings Taken from soft, new spring growth of woody plants Root easy but require more attention Usually 3 to 5 inches in length 2 or 3 nodes Cut at 45 degree angles ¼ inch below a node 1/3 of lower leaves are removed These are cuttings taken from soft, new spring growth of woody plants. Softwood cuttings root easy but require more attention. Cuttings are usually 3 to 5 inches in length with 2 or 3 nodes. The stems are cut at a 45 degree angle approximately ¼ inch below a node. Then, to reduce water loss through transpiration, 1/3 of the lower leaves are removed. Large leaves can be cut in half to reduce wilting and thus increasing the chances of rooting. All flower buds should be removed from the cuttings.

Herbaceous Cuttings Also considered softwood cuttings Numerous succulent greenhouse plants 3 to 4 inches long Contain several leaves Root easily Herbaceous cuttings are also considered softwood cuttings. Numerous succulent greenhouse plants are propagated by herbaceous cuttings. These cuttings are 3 to 4 inches long and contain several leaves. Many species root easily. Examples include geranium, carnation, chrysanthemum, and coleus.

Semi-hardwood Cuttings Woody, broad leaved plants Taken in the summer from new shoots 3 to 6 inches in length Handled the same as softwood cuttings These are cuttings prepared from woody, broad leaved plants. The cuttings are taken in the summer from new shoots that have partially matured. The cuttings are 3 to 6 inches in length and are handled in the same manner as softwood cuttings.

Hardwood Cuttings Prepared during the dormant season Deciduous or evergreen plants 6 to 8 inches in length Taken from year old wood Form callus tissue during the winter Develop roots in the spring These are cuttings prepared during the dormant season from either deciduous or evergreen plants. Cuttings are usually 6 to 8 inches in length and taken from one-year-old wood. The cuttings are allowed to form callus tissue during the winter. The callus tissue is white tissue that forms over the wounded area or base of the cuttings. This is where new roots sprout. In the spring, the callused cuttings develop roots.

Conifer Cuttings Early winter Narrowleaf evergreens May take several months to produce roots Conifer or narrowleaf evergreens are propagated by hardwood cuttings obtained from plants in early winter. They may require several months to produce an adequate root system. Juniper, yew, spruce, and pine are examples of conifers that can be propagated with this method.

Leaf Cuttings Consist of a leaf blade or leaf blade with petiole Used when plant material is scarce Used when a large number of new plants are needed Houseplants or foliage plants A leaf cutting consists of a leaf blade or a leaf blade with petiole attached. Leaf cuttings are used when the plant material is scarce and a large number of new plants are needed. House plants or foliage plants are often propagated by this method. Examples are Snake Plants, Rex Begonia, African Violet

Leaf Cuttings Cont. Leaf blades can be cut into pieces and inserted into medium See Figure 2 in handout Some leaves can be cut on the primary veins and laid flat on top of the growing medium. See Figure 3 in handout Leaf and petiole cuttings are place petiole down the the medium See Figure 4 in handout Snake plant leaf blades are cut into pieces approximately 3 to 5 inches in length and inserted into a growing medium. The bases of the leaf cuttings will produce new roots and shoots. See Figure 2 Rex begonia plants can be started by using the leaf blade. The primary veins are cut and the leaf cutting is laid flat on top of the growing medium. The leaf, with the upper side exposed, is pinned down, usually with some type of pin. New plants are formed at each point where the veins were cut. See Figure 3 African violet is commonly propagated by using the leaf blade with the petiole attached. The petiole is inserted in the growing medium. New roots and shoots will emerge from the base of the petiole. The old leaf is usually pinched off and discarded. The new plants are separated and replanted. See Figure 4

Leaf Bud Cuttings Consist of a leaf, petiole, and a short piece of stem with lateral bud. Must have well developed buds, and healthy, actively growing leaves. Insert in medium with the lateral bud just below the surface See Figure 5 in handout A leaf-bud cutting consists of a leaf, petiole, and a short piece of stem with the lateral bud. The leaf-bud cutting method is extremely valuable to the propagator, especially if the woody plant material is scarce and many new plants are needed. Leaf-bud cuttings should only be made from plant material having well developed buds, and healthy, actively growing leaves. The stem piece is inserted in the growing medium with the lateral bud just below the medium surface. A new plant will develop from the lateral bud. Plants such as rhododendron, camellia, maple, and magnolia can be propagated using this method.

Root Cuttings Made from root pieces of young plants During late winter or early spring Roots are dug, cleaned, and treated with fungicide 2 to 6 inches in length Placed horizontally or vertically Quite laborious Root cuttings are made from root pieces of young plants during late winter or early spring. Roots are dug, cleaned, and treated with a fungicide. Root pieces are cut 2 to 6 inches in length. They are either placed horizontally, approximately 2 inches deep in the growing medium, or vertically, with the root end that was closest to the crown of the plant at the top. To avoid planting the roots upside down, the propagators will cut the root closest to the main stem with a straight cut and the root portion further from the main stem with a slant cut. Plants that naturally produce suckers are easily propagated by root cuttings. However, propagators find that preparation of root cuttings are quite laborious and therefore will use other propagation methods. Raspberries are commonly propagated with root cuttings.

Rooting Hormones Material that promote the development of roots Applied to the bases of the cuttings Powders or Solutions Do not use too much, it may cause the stem to rot Rooting hormones, or materials that promote the development of roots, are used to increase the percentage of cuttings that root. The cuttings of some plants root easily and may not need hormone treatments. However, even these plants will make roots more quickly and uniformly when treated with a rooting hormone. The hormones are applied to the bases of the cuttings. They can be either powders or liquid solutions. You only need a small amount of hormone because if you use too much it may cause the stem to rot and thus prevent root formation.

Root-Inducing Environment High humidity to reduce water loss Indirect sunlight Growing medium Since many of the types of cuttings have leaves but no roots, it is very important to keep them in a high humidity environment to reduce water loss through transpiration. Sunlight is important in the growth and development of cuttings, but direct sunlight increases transpiration. Therefore, cuttings need indirect sun light. The type of growing medium used for rooting cuttings varies depending on the type of cutting and the cultural practices. Many different types of media can be used to root cuttings. Whatever type is used needs to hold moisture, provide good aeration and drainage, as well as be disease and weed free.

Types of Growing Medium Peat moss & perlite mixture 1 to 1 ratio will hold moisture and provide aeration Vermiculite Sterile and has high moisture retention Sand Provides aeration but does not retain moisture Sand & peat moss mixture 1 to 1 or 2 to 1 ratio, increases moisture retention

Summary Asexual propagation is the propagation of plants from stems, leaves, or roots of a parent plant Cuttings are the most popular form Cuttings are often treated with a rooting hormone The environment is very important for successful rooting