Gerald Klingaman, Ph.D., is an emeritus professor of horticulture at the University of Arkansas. He is now working full time as operations director at the Botanical Garden of the Ozarks. He gardens in Fayetteville.

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Make More Green
by Gerald Klingaman       #Containers   #How to   #Propagation

As winter approaches, gardeners are faced with a dilemma – keep the plants or the spouse? I suspect more than one marriage has ended over a fundamental disagreement about the need to move the patio jungle into the living room. Good gardeners live on a slippery slope because they want their patio plants to flourish during their respite outside, and before you know it, it’s decision time. Do I save the philodendron or the favorite easy chair?

But there is a way out – propagate the overgrown vegetation and bring in small, manageable plants. Leave the big ones outside to see if they will survive the icy blast of winter. Of course they won’t, but you can appease your conscience by proclaiming their sacrifice to be part of a winter hardiness test you were conducting.

Terminal cuttings of several houseplants ready to stick into the rooting bag.

Cutting Propagation Basics
While there are a number of different methods of plant propagation, here we will concentrate on just one kind – cutting propagation. Cuttings are used to propagate trees and shrubs, herbaceous perennials and a wide array of houseplants.

Because plants vary so much in size and shape, a number of different cutting types are used in propagation. The most basic cutting is called a terminal cutting, consisting of a stem with a few leaves attached. The length of the stem will vary depending on the kind of plant, but 3 to 5 inches is a good range for a wide variety of plants. Usually the cutting will contain four to six leaves. For easily rooted plants, the basal cut can be anywhere on the stem, but for more difficult to root plants, make the cut just below a node. Don’t be greedy and make the cutting too big because large cuttings with lots of leaves loose water quickly. Wilted cuttings quickly turn into dead cuttings. Avoid stems that have flowers. For example, chrysanthemums root easily in the early part of summer before flower buds form, but after the buds appear rooting is much more difficult.

When you try leaf bud cuttings of pothos, crowd as many as possible into the pot. • Each leaf of a vining plant such as pothos is a potential cutting.

Leaf-bud Cuttings
Single-eye or leaf bud cuttings are used to propagate plants with large leaves or those that require lots of growing points to create a full appearance. These cuttings consist of an inch of stem above and below the resting bud and a leaf. The term “single-eye” is usually used to refer to plants that have alternate leaf arrangement such as pothos or nephytis, while “leaf bud” is used for plants with opposite arrangement such as coleus or hydrangea. For leaf bud cuttings with opposite leaves, just trim off one of the leaves. Plants with really large leaves – such as some coleus cultivars, hydrangea cuttings, rubber plant and other similar plants – usually have their leaves cut in half, simply so they don’t take up so much room in propagation.

This new plant started from a fallen leaf of a burro’s tail sedum.

New rhizomes are emerging from this mother-in-law’s tongue, but it took almost eight months for them to appear.

Leaf Cuttings
Some plants have the ability to regenerate new plants directly from leaves using leaf cuttings. Leaf cuttings are used only for houseplant propagation, and if another method of propagation is possible, it is preferred because this is a slow procedure. Relatively few species of plants can be propagated by leaf cuttings with African violets and its kin, succulent leafed plants in the jade plant family, some sedums and hens-and-chicks, many peperomias, the fleshy leafed begonias such as rex and beefsteak begonias, sansevieria, and a few other miscellaneous plants making up the list. Leaf cuttings are unique in the vegetable world in that the plant must not only form new roots, it must form a new shoot. Some plants such as rubber plant and chrysanthemum form roots from a leaf but lack the ability to produce a new vegetative shoot so you are left with a eunuch.

Succulent leaves from sedums and echeverias can be simply scattered on the surface of a pot like so many jellybeans and they will eventually root and form new plants. African violet cuttings are made by removing a mature leaf and petiole and then sticking the petiole in the rooting medium. Rex begonia leaves may either be laid flat on moist media or cut into pie shaped wedges (each wedge must contain a major leaf vein) and inserting the pointed end into the media. Usually eight to ten weeks is required to produce a new growing point using leaf cuttings, so patience is a virtue with this type of propagation.

Moisten the stem and then dip the cuttings in rooting hormone.

Using Rooting Hormones
Most plants have the ability to form roots on their own, but the speed and uniformity of rooting can be increased dramatically by using one of the commercially available rooting hormones. The hormone involved, auxin, occurs naturally in plants. Auxin has many functions including stimulating cell division, which is why flowers turn to face the brightest location in the garden, stems grow upright when tipped over, and why the apical growing point suppresses the growth of buds below it on the stem. Stimulation of rooting, while important to propagators, is a relatively minor role for this important plant hormone.

Rooting hormones are available from most garden centers and home stores under brand names such as Rootone or Dip’N Grow. The first is a powder that contains auxin at a concentration of 1000 parts per million active ingredients; Dip’N Grow is a liquid that is diluted in water and can have a range of concentrations depending on the amount of water added. If stored in a cool, dry location, they maintain their effectiveness for years. The 1000 ppm concentration of the powder is ideal for most houseplants, but a higher concentration is desirable if you get ambitious and attempt to root woody plants.

The rooting powder is applied by first dipping the bottom half inch of the cutting in water and then dipping this portion in the hormone. Tap the cutting to remove any excess powder. To avoid getting moisture and debris in the hormone container, remove a small quantity of the powder before dipping the cutting and then discard any unused material. When liquid hormones are used, the basal 1/2 inch is inserted into the solution for a five second count.

A 6-inch pot, fresh potting soil, a plastic bag and a coat hanger make an ideal rooting environment for many houseplants.

Creating the Right Rooting Environment
The most conspicuous role for roots is water uptake, so obviously cuttings without roots get dry in a hurry. Hence it follows that the most critical environmental requirement for rooting is to provide conditions that keep the plant from wilting. The most obvious way to prevent wilting is to simply stick the cuttings in a vase and allow them to root in standing water. This actually works for a few plants such as pothos, coleus and even African violet leaves, but the roots formed in this low oxygen environment don’t function very well when finally transplanted to soil. Oftentimes a new root system will have to form when the water-rooted cuttings are transplanted to soil, so rooting in soil is much preferred to rooting in water.

Crowd the cuttings in, mixing and matching plants as needed to fill the rooting bag.

Place the finished pot in a location where it receives bright light but not direct sun.

An easy way to prevent wilting is to provide a high humidity environment that prevents excessive water loss. On a small scale this can be accomplished by using a plastic covered rooting pot or, if more cuttings are needed, to build a rooting box. The plastic traps the water vapor released from the reservoir of moist soil, keeping the air at 100 percent humidity, which prevents wilting. I have had plants survive in this terrarium-like environment for two years with absolutely no attention. Because no moisture is lost from the system, they will not dry out. Use any good, high quality potting media for rooting. To ensure you have the proper moisture level in the media, wet the mix the evening before you take your cuttings. Depending on the ease of rooting, roots will begin appearing in three to six weeks for most herbaceous plants and houseplants. You can build a similar setup from a two-liter soft drink container by cutting the jug in half about 4 inches from the base. Put moist soil in place, stick your cuttings in, and then use tape to reattach the top of the container. Rooting containers must never be placed in direct sun or the plants will be roasted, just like they would be if left in the car on a sunny afternoon in a Wal-Mart parking lot.

You can crowd a dozen or more cuttings into the container, mixing and matching a wide assortment of plants. Don’t worry if cuttings touch. If moldy leaves show up in a couple of weeks, open the bag and remove the leaves. Or, if you want to propagate a new favorite plant, the rooting bag can be used to produce a nice full plant in short order. If this is your goal, don’t be stingy with cuttings. To make a nice attractive pothos pot, stick 12 to 15 single eye cuttings in a 6-inch pot. Really crowd them in. Each leaf bud will produce a new shoot and in a few months you will have a full, well-proportioned pot. For cuttings with upright growth such as jade plant, nephytis or aluminum plant, stick three to five terminal cuttings all in one spot in the center of the pot. As the roots form, the plants will begin to grow and in no time you will have an attractive, full plant. If you use only one cutting to start a new plant, you will eventually be able to grow a nice plant but it will take years to do so, not months.

After a month or so, give the plants a gentle tug to see if they have rooted. Once they are rooted, remove the plastic bag and allow the roots to develop a couple weeks longer before transplanting. If you were propagating just one kind of plant in the pot, no transplanting is needed. Make the vow now to go easy on the fertilizer so that this new baby won’t turn into another giant that will overpower your living room when winter rolls around.


A version of this article appeared in an October 2003 print edition of State-by-State Gardening Magazine.
Photography courtesy of Gerald Klingaman.


Posted: 01/17/18   RSS | Print


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