Plant propagation introduction
Plant propagation is the one activity where subtracting and dividing equals multiplication. Nature has already provided everything the gardener needs to replicate almost every type of plant for (almost) free. With just a bit of knowledge and a pinch of an herb or a piece of a root you can easily and endlessly recycle those marvelous gifts from the ground.
Did you know that there are many methods of propagating plants but that not all methods work on all plants? However, most plants within a plant “type” are propagated using the same method. For example, perennials are very suited for root division while annuals are more suited to propagation by seed. Trees and shrubs are more suited to propagation by some type of cutting.
Tip for plant propagation
Sterilize reused equipment in a mild bleach solution.
Getting started with plant propagation
Only basic supplies are required.
First, stock up on containers: Containers can be anything that will hold at least 1 inch of potting soil, or some other growing medium. Try egg cartons, old milk containers, or plastic cups and remember to punch out some drainage holes. For best results, recycle your commercially made containers.
Next, decide on a growing medium: There are many excellent prepackaged options or you can make your own. The ingredients are typically : Peat Moss, Perlite, Vermiculite
Select a site: Plants need light, moderate temperatures, and air.
Young plants need at least 12 hours of light per day.
Temperatures are ideal around 70 degrees although the temperature of the growing
Air Circulation shulod be balanced with humidity. Try covering pots with plastic humidity domes or clear plastic bags.
Start with healthy plant and seeds: Before attempting any propagation methods, perform a quick health check on the parent. Look carefully for signs of pests such as aphids, mites, thrips, whiteflies, or diseases.
Recipes for growing mix
For seeds: 2 parts peat moss, 1 part perlite or vermiculite
For cuttings: 1 part perlite, 1 part vermiculite
For growing: 2 parts peat moss, 1 part perlite, 1 part vermiculite
Propagation by seed
Propagation by seed is the easiest, cheapest, and most popular method available. There are endless varieties of seeds available through local nurseries, hardware stores, seed catalogs or your grandmothers garden. Some seeds germinate quickly while others need some encouragement. Seeds with a hard protective coating (the Endosperm) will require a pre-treatment before the seed will germinate. Some seeds should be planted the next growing season while others may be capable of lying dormant for years. For more details on a specific seed, follow package instructions.
Seed Sowing Basics
The differences in the size and makeup of a seeds’ characteristic’s account for the differences in the germination time, planting depth and seedling growth. As a general rule only cover the seed with as much soil as the seeds own depth. If you have seed packets, always follow the directions on the packet for best results.
Very fine seed can be planted using the following methods:
Place just under the surface of the soil.
Dust on top of the soil
Lightly mix with sand and spread on the soil
Medium to large sized seed can be planted using the following methods:
- Place under the soil surface by varying degrees of depth depending on the size of the seed.
- If the Endosperm is extremely hard, a presoaking, a chemical pre-treatment, orstratification may be required.
Stratification is the layering of seed in a pot or boxwith a medium such as sand and peat moss and refrigerating or cooling them for a period of time. Some require 6 weeks while others require several months.
Scarification is the nicking or thinning of the outer coat of the seed to allow moisture to penetrate the seed to initiate germination.
Presoaking is usually accomplished by soaking the seed in tepid to hot water overnight before planting or sowing. Occasionally seed may need to be chemically soaked in order to break the dormancy of the seed and initiate germination.
For all types, the seed and soil should be kept moist until the second set of leaves appear.
Propagation by stem cuttings
Stem cuttings are easy to accomplish. There are three main types of stem cuttings: softwood, semi hardwood, and hardwood. Stem cutting will duplicate the parent plant exactly, unlike seeds where results can vary. Stem cuttings are the recommended method for most trees and shrubs.
Stem cuttings are actually sections of young stems that will root and grow into perfect replicas of the original. Herbaceous, softwood, and hardwood stems have the ability to root, although some root more quickly than others depending of their age and firmness. Herbaceous cuttings such as begonias, coleus, and basil root most easily; these are examples of soft stemmed, non-woody plants.
Softwood : Softwood cuttings come from the new growth from young stems of woody plants; these will root but not as quickly as herbaceous cuttings. Look for stems that range from soft to slightly firm.
Hardwood: Hardwood cuttings come from dormant, year-old stems. They should be year old for this kind of propagation. Hardwood cuttings are more difficult to root than softwood cuttings. They require a cold period of dormancy until early spring, when they can be planted outdoors in a cold frame or sheltered nursery bed.
Propagation by root cuttings
Root Cuttings: Root cuttings, like stem cuttings, recreate whatever parts of the plant that are missing. Root cuttings are an easy and reliable way to propagate many types of perennials, shrubs, vines, and trees.
Variations In Root System Structure: The type of root system structure will usually dictate the best method of propagation.
Fibrous roots: Many shrubs, trees, and perennials have fibrous roots, with a branching system of similar size roots that honeycomb upper layers of the soil. Roots develop from adventitious buds located at the base of the stem. These roots are suitable for separation by division, unlike taproots.
Taproots: These are thick, fleshy main roots that dig deep into the soil, producing smaller side roots along their length. Most taprooted plants don’t transplant well because mature taproots are easily disturbed. But some, carrots for example, can be sliced into sections to make into cuttings.
Creeping growth: Plants with spreading stems ( called rhizomes or stolons) sprout shoots and roots as they wander and can cover a broad territory. Spearmint for example can spread up to 4’ a year and is easy to propagate.
Rhizomes / Stolons: Underground stems that send out roots and shoots from its nodes, those that grow on the ground are called stolons.
Crown: The part of a plant where stem and roots emerge from the ground. The best root cuttings often come from sections of root closest to the crown.
Meristem: The portion of a plant with unspecialized cells that contain full genetic memory.
Adventitious Buds: Suckers that emerge from root cuttings come from adventitious buds, and are generated as a response to the separation from their parent plant.
Propagation by root division
Root Division is an exceptionally fast and simple method for propagating plants. The plant is ready for the garden with intact roots and shoots. This method is used for propagating bulbs, perennials and some shrubs. Most perennials do best when divided every several years.
Bulbs are sections of stem with food-storing leaves surrounding a budded embryo. Bulbs may have a single set of fleshy leaves that look solid like a tulip or they can be layered like an onion. Roots vary in appearance but all serve the purpose of food-storage for the shoot within. Bulbs are short and normally globe shaped, tipped with either a growing point or with tissue containing yet-undeveloped flowers.
Corms : Like bulbs, corms are food-storing underground stems. They are often confused with bulbs. Crocus is an example. When dormant, a new corm can be found growing on top of the previous season’s shriveled or depleted corm.
Tubers: Tuberous roots, such as those of potatoes, attach to a central crown, which contains the growing roots attached to a central crown; they go dormant when the top growth goes dormant. Tuberous roots can be propagated by cutting them into sections so that each has at least one bud.
Propagation by layering
Layering is a form of propagation that occurs when a branch is rooted while still connected to the parent plant. The stem is bent to the ground, nicked on the bottom to encourage rooting then buried Used primarily for propagating woody plants. Almost no concern about wilting, hardiness, or hardening off. Slower than stem cuttings.
Compound Layering: Long flexible vine stems, using ground layering techniques, can be woven in and out of the ground to produce several layered offspring.
Tip Layering: Trailing plants such as blackberries, dewberries, boysenberries, and raspberries arch branches sinking their tips down into the soil. The stem tip then sprouts into a new plant.
Mound or Stool Layering: The entire plant is devoted to the layering process. Allowed to grow for a year after planting, the plant is cut back hard the following spring. As new stems emerge and grow, the bottom half of the plant is covered with sandy soil.
No high tech equipment is needed for layering. A hoe, sharp pruning knife or a flat rock can be used to weight the submerged stem in place.Timing -Ground layering works best if started in late winter or early spring.Late summer is the best time for tip layering.Rooting Hormones - Hormones called auxins are responsible for initiating rooting in layered stems. Excellent brands of rooting hormones are available at your local gardening center.