Gardening has got to be the greatest hobby in the entire world. There is no other pastime where you can take the object of your affection and admiration, the very thing that makes your hobby possible, the plant, and increase its numbers as you see fit at little or no additional charge! If you plant a golf ball, no matter how hard you try, it will never grow another golf ball. If you cut off a piece of a golf club, it will never regenerate into a whole golf club. You cannot divide a golf club and expect that it will ever be a functional golf club again. The same holds true for all of the necessary equipment for most other hobbies. To be able to make one plant into many plants is one of the most enjoyable parts of being a gardener, not to mention one of the most cost effective. Propagating successfully will also make you very popular among your gardening friends! There are basically two types of propagation. Asexual propagation refers to multiplying the number of plants by using parts of the plant such as leaves, stems, and roots to regenerate into a new plant. Sexual propagation is the union of pollen (male) and egg (female) to produce a seed.
Asexual or Vegetative Propagation
Asexual propagation has many advantages. Most importantly, it is a way to ensure an exact genetic copy of the parent plant. It is also a fast way to a mature plant and makes it easy to share plants that are not ready to be dug up and divided. For some cultivars, this may be the only way they can be propagated. The most common methods of asexual propagation are cuttings, layering, grafting, budding, separation and division. Some methods are better suited than others for the propagation of certain plants.
Growing plants from cuttings is easier than most people think. A cutting is a small section of a plant that is severed from the parent with a sharp knife and usually treated with a root stimulant to encourage growth so it will regenerate into a new plant. Cuttings can be a portion of leaf, stem or root. Stem cuttings are most common and they can take the form of softwood, which are cuttings of new growth, semi-hardwood, which are cutting of new growth later in the season after it has hardened slightly, and hardwood cuttings, which are taken when the plant is dormant. When taking the cutting, cut off three to six inches and remove most of the leaves and all flowers or buds. This insures the plants energy will go towards root development. Cuttings root best when placed in a sterile rooting medium such as coarse perlite or vermiculite. An even better medium would be an equal mix of perlite, vermiculite and peat moss to enhance moisture retention but still be loose enough to allow roots to easily develop. A mist bed that sprays a fine mist of water over the cuttings many times a day is an excellent option. If one is not available, you can start the cuttings in a pot or shallow rooting tray. Moisten the medium and insert the treated cuttings with at least one node below the surface. Place a clear plastic bag over the cuttings to increase the relative humidity. This decreases moisture loss and still allows air circulation. Check often and loosen plastic if condensation develops inside, too much moisture will cause your cuttings to rot. Place in bright but not direct light and do not allow them to dry out. Tug gently after 2 or 3 weeks, if you feel resistance, the cutting has rooted. Dig them out; do not pull and plant in soil in individual pots.
Layering is a great way to produce more plants. The process involves developing roots on a stem that is still attached to the parent plant. When the stem has rooted, it is separated from the parent and is a new plant. Often plants will do this by themselves. Simple layering happens when you bend a branch of a mature plant to the ground and cover it with soil, leaving the terminal end exposed. Wounding the side of the branch that is underground will help root development. When the branch is adequately rooted, detach and transplant. Compound layering is similar to simple layering, except that you alternately cover and expose a flexible branch, wounding each stem section that is covered with soil. Separate each plant after roots have developed and transplant. With Tip layering, the tip of a current season shoot is planted in the ground about 3 or 4 inches deep. The tip of the branch will begin to grow down and then change directions to curve upwards. Roots will grow at the bend. Remove the plant from the parent after one season and transplant. In Mound layering, you cut the plant back to the ground in the dormant season and then mound soil around the base. The newly developed shoots will form roots and become new plants. Air layering is a good choice for thick-stemmed plants. Choose a well-developed shoot and cut a wound in the stem exposing the cambium layer. Wrap the wounded area with moistened sphagnum peat moss and tightly cover it with plastic securing top and bottom with tape or rubber bands. Check frequently and do not let the peat moss dry out. When the roots can be seen in the peat moss, cut the new plant off just below the root ball and replant.
Grafting is widely used in the nursery industry, often with fruit and nut tree production. It involves joining together two different plants so that they continue to grow as one. Only plants that are closely related can be grafted successfully. The scion or the desired plant is joined with the under stock or parent plant that develops the root system. After the graft has grown together, remove the top of the under stock. This process is done when new growth starts in early spring.
Budding is similar to grafting except one newly developed latent bud is joined with the rootstock. This is usually done in mid summer. Both grafting and budding are not widely used in the home garden.
Separation is the term that applied when plants produce new bulbs beside the old one, an example would be daffodils and tulips. These plants need to be dug up and separated every three to five years to continue blooming. Some plants like gladiolus and crocus have corms, which are similar to bulbs. These plants can form tiny cormels around the large corm. The cormels are separated from the parent and replanted to become new plants.
My favorite way to propagate plants is division. The plants do most of the work and the rest is relatively easy! Division is necessary to keep some plants healthy and vigorously growing. Perhaps the easiest division is when the plant sends out suckers. Suckers or runners develop below the surface in the area around the crown; they are simply dug up and replanted. The new plants will need to be trimmed back to encourage growth and kept moist until established. Offsets are branches that develop at the base of the parent plant. They may look like a thick stem with a rosette of leaves. They can be severed from the parent when they have developed a root system and then rooted like a cutting. These are common in cacti and many bromeliads. Many perennials and some shrubs can be divided at the point where the roots come into contact with the shoots of growth or the crown. There are many methods, but generally the entire plant is dug up in late winter or early spring. If the plant has multiple stems growing from the crown and a fibrous root system, it can be cut from the top to the bottom along the stem growth. Plant the divisions quickly so that they do not dry out. Herbaceous perennials like daylilies, hostas, and asters that grow in large clumps can simply be dug up and pulled apart, usually in the early spring. This can be done by removing some of the plants around the outside of the root ball or by lifting the entire clump out of the ground and separating by hand. If the clump does not come apart easily you can use a sharp knife or pruners to cut it into pieces. Be sure to include good sprouts and roots on each piece. Try not to divide the plant into pieces that are too small to thrive. Replant the divisions at the same depth as they were growing before and keep them well watered until they become established.
The most common and least expensive method of propagating plants by far is from the seed. Flowers are beautiful to look at but their ultimate purpose is to produce seed to perpetuate their species. Seeds become fertilized embryos when the male pollen from the stamen pollinates the female pistil part of the flower. When the right conditions for light, oxygen and temperature are met, the seed will come out of dormancy and begin to grow. Not all seedlings are exact duplicates of their parents, but variations might be able to adapt and survive better.
In order to grow quality plants, start with seed varieties adapted your area and make your choices based on the desired growth habit, size and color. A great resource for this information is your local County Extension Agent. The most important aspect of sowing seeds is the timing. Seeds can be sown directly into the soil outside according to the date on the package or you can start them indoors 6 to 8 weeks before the last frost to maximize bloom time. When starting seeds indoors, it is important to use a well-prepared medium that is sterile, uniform and still loose and well aerated. A good general recipe is 1/3 sterilized soil, 1/3 sand or vermiculite and 1/3 peat moss. Any clean trays or pots can be used to start your seeds. Moisten the medium with warm water and plant the seeds about an inch apart. Cover the seeds with a fine grade perlite or potting mix and lightly water. Label each type of seed and cover your containers with plastic until the seeds sprout to maintain high humidity. Check frequently; if conditions are too wet you can experience damping off, which is a fungal disease that attacks young seedlings, or other disease problems. Most seeds will germinate when the temperature is between 70 and 75 degrees. A heating mat could be helpful here, especially when the nighttime temperatures inside fall below what the seeds require. After the seeds germinate they will need 12 to 14 hours of light a day, a fluorescent light can be used to meet this requirement. The young plants will not need such warm temperatures after germination; they will grow best with daytime temperatures about 60 to 65; nighttime temperatures can be 10 degrees colder. When the seedlings are about two weeks old the stored food from the seed, which was enough to get the plant going, is about depleted and a weak solution of a balanced liquid fertilizer is helpful to ensure vigorous growth. When the seedlings are about 2 inches tall or they have their second set of leaves or true leaves, they can be thinned if necessary and transplanted into larger growing containers. The process of hardening off can begin one or two weeks before being planted outdoors. Hardening off refers to exposing young plants to conditions outdoors over a period of time. The number of hours a day and the amount of sunlight a plant receives should be increased for about a week until the plant can be left out doors as long as there is no danger of frost. When plants are sufficiently hardened and the danger of frost has passed you can begin planting outdoors. Pick an overcast day to set out your young plant to lessen shock. Plant in well-prepared beds with good drainage, check frequently and water when needed.
As the temperature gradually warms and spring officially arrives, you will probably be spending as much time outdoors as possible enjoying time with your new plants (I know I will!). Whether they were born from seed or vegetative clones, there is nothing more satisfying than playing a part in the procreation of the very thing that makes gardening possible, the plant!