Propagating California Native Plants

This is the URL to get the PDF book on propagating California Natives from Santa Ana Botanical Gardens.  This text was referenced in today's talk! 

Follows are the handouts, if you didn't get them in class.

A Reading List for California Plant and their Propagation

Assembling California (Annals of the Former World); McPhee, John, Farrar, Straus and Giroux Publishers, ©1993 A small and quick read that is as delightful as it is informative. Find out about the soils of the California Floristic Provence and how they 'call the shots' for many of the plants we have in this part of the world. It's fascinating!

California Native Plants for the Garden; Borstein, Carol, Fross, David and O'Brien, Bart, Cachuma Press © 2005 I was around at this books' publication and it really caused a storm – the photos of California plants put to creative use in glossy photographs made this book fly off the shelves! It really is a delightful and colorful addition to those gardens using plants native to California.

California Plants, A Guide to Our Iconic Flora; Ritter, Matt, © 2018 Pacific Street Publishing; A concise guide with many color photos! A foreward from the Goveror, Edmund Brown! Newly in print so it has more up to date plant names. Good photos make identification of plants a cinch.

California Plant Families; Keater, Glenn, University of California Press, © 2009 Keator is one of the more prolific botanists on the scene at this time, and this is written with authority – Illustrations by Margaret J. Steunenberg, and beautifully done. Definitely a must have if you are really getting into Californian plants.

Complete Garden Guide to the Native Perennials of California; Keator, Glenn, Chronical Books, © 1990 I got my copy when it was rumored that it was no longer published – those rumors came true a few years later, but I know you can buy used copies of this marvelous book from used book outlets. As above, this is hand-illustrated with detailed drawings and is definitely a keeper.

Gardening with a Wild Heart; Lowery, Judith Larner; University of California Press, © 2007 Not a book of facts and figures, but a story of California Natives and a woman's love for them. When I first started in California Natives, I was ordering seeds from Larner Seeds and this is the woman we meet on these pages. Lowery's wonderful measured point of view comes thru on a variety of essays that include discussions of wildflower gardening, the ecology of native grasses, wildland seed-collecting, principles of natural design, and plant/animal interactions.

Seed Propagation of Native California Plants; Emory, Dana; Emory was the plant propagator for the Santa Barbara Botanical Garden in the 1950's. There was no book on propagating California Native Seeds, and it was Emory's job to do just that. So Dana Emory wrote the book. It was never meant for publishing, being just the notes year after year that were accumalated. If you're looking for a thriller, this aint it. However, even though somewhat dated, it is a resource and if you can find one, it belongs on your shelf. The only one for sale I found writing this was priced at $143.52!

A List of Cismontane chaparral plant species

In Central and Southern California chaparral forms a dominant habitat. Members of the chaparral biota native to California, all of which tend to regrow quickly after fires, include:

• Adenostoma fasciculatum, chamise
• Adenostoma sparsifolium, redshanks
• Arctostaphylos spp., manzanita
• Ceanothus spp., ceanothus
• Cercocarpus spp., mountain mahogany
• Cneoridium dumosum, bush rue
• Eriogonum fasciculatum, California buckwheat
• Garrya spp., silk-tassel bush
• Hesperoyucca whipplei, yucca
• Heteromeles arbutifolia, toyon
• Acmispon glaber, deerweed
• Malosma laurina, laurel sumac
• Marah macrocarpus, wild cucumber
• Mimulus aurantiacus, bush monkeyflower
• Pickeringia montana, chaparral pea
• Prunus ilicifolia, islay or hollyleaf cherry
• Quercus berberidifolia, scrub oak
• Q. dumosa, scrub oak
• Q. wislizenii var. frutescens
• Rhamnus californica, California coffeeberry
• Rhus integrifolia, lemonade berry
• Rhus ovata, sugar bush
• Salvia apiana, white sage
• Salvia mellifera, black sage
• Xylococcus bicolor, mission manzanita

Go to https://lagardennotes.blogspot.com/2018/10/propagating-california-native-plants.html to get the notes on this class.

david

Handout From Katarina Eriksson

Plant Propagation by Leaf Cuttings:

Instructions for the Home Gardener

by Katarina Eriksson, Horticulturist.

Owner of Kat Eriksson’s Landscaping & High End Garden Maintenance

katsflowers@gmail.com

2017

Why use vegetative propagation? VP.

The new plants are clones – Genetically identical to parent plant, not sexual propagation with 2 parents, as in seeds.

VP. Preserves unusual and valuable plant traits that may not pass with seed.

VP. Used to reproduce plants that seldom flower or are sterile.

VP. Can be much faster than growing an equivalent plant by seed. Some like african violet will bloom faster than seedlings.

And it's fun!!!!

WHAT YOU NEED, Types of Media used for propagation:

(All equipment should be clean and sterile at all times, Use rubbing alcohol or mouthwash on the blades and hard surfaces).

Sterile soil, and a clean bucket or container to mix in.

Sterile pots, 3 to 4 inch is good.

Sharp knife or scissors/pruner or snips.

Rooting hormone or willow water (see last page) paper towel or clean rags.

Chopsticks.

Hair pins or thin wire.

Container to act like a mini greenhouse, like clear plastic shoe box. Can re-use clean plastic food containers with lids.

Watering can with soft nozzle, spray bottle, clear filtered or rain water.

Personal safety: Wear mask when mixing soils or handling chemicals that can irritate breathing. I use medical gloves when mixing soil. Safety glasses are recommended for contact wearers. I use a very sharp blade on my cutters and knifes, keep them sterilized and always point away from you. Use common sense and safety first!

CHOOSE FROM ONE OF THESE PROPAGATION SOIL MIXES.

• ½ clean sand with ½ good quality potting soil. NOT STERILE

OR

• ½ clean sand with ½ moistened peat moss, or coir. (Good for Begonias, African Violets and succulents)

OR

• ⅓ perlite and ⅓ vermiculite with ⅓ peat or coir. (This is my usual mix for most plants. it's completely sterile so less chance of fungal rot disease.)

OR

• ⅓ clean sand with ⅓ perlite and ⅓ or less vermiculite. (best for succulents, and plants that need very good drainage)
• (cactus and succulents can be in straight clean sand)

MIX IN A CLEAN BIN OR BUCKET ADD WATER VERY SLOWLY. (The propagation medium should be as sterile as you can make it and moistened before use. Many organic materials, like coir or peat moss, resists wetting at first. (Its aquaphobic). Warm water helps.

Be sure to apply warm water (Distilled or rain water is best) slowly while mixing to obtain uniform distribution. This may require 2-3 applications a little at a time. It is not uncommon for a medium to look wet on the surface but to be powdery dry in the middle. A well moistened media will make it easier to stick in the cuttings later on. But if it's too wet, it may rot your cuttings, it should be able to be squeezed in a ball and not be soggy.

Non chlorinated or rain water is best, and a watering can with a soft rain spout. MAKE SURE IT'S THOROUGHLY MIXED AND MOIST.

LEAF CUTTINGS, Vegetative reproduction

Use with African Violet, Mother-in-law tongue, piggy back plant, etc.

USE ONLY HEALTHY LEAVES, not too old or too young, if spotted, diseased or damaged, you may have less than average chance of success.

Few plants can be propagated from just a leaf or a section of a leaf. (Not all plants can be propagated this way, they usually just decay) Because leaf cuttings do not include an axillary bud, they can be used only for plants that are capable of forming adventitious buds.

Because leaf cuttings do not include an axillary bud (Axillary bud refers to structures that develop in an unusual place) they can be used only for plants that are capable of forming Adventitious buds.

Some leaves develop adventitious buds, which then form adventitious roots, as part of vegetative reproduction; e.g. Piggyback plant (Tolmiea menziesii) and mother-of-thousands (Kalanchoe daigremontiana). The adventitious plantlets then drop off the parent plant and develop as separate clones of the parent.

SOME EASY PLANTS THAT MAKE LEAF CUTTINGS

Leaf cuttings are used almost exclusively for propagating of some indoor plants and succulents, these are common easy plants to try, e.g. African Violet, Gloxinias, Begonia - rhizome types, Peperomia, Episcia, ZZ plant, and piggyback plant, which is a Calif native forest plant.

Some succulents are usually propagated by leaf cuttings. Genera typically propagated by leaf cuttings include but are not limited to: Gasteria spp. Christmas cactus, Haworthia, Hoya, Sansevieria, Kalanchoe, Sedum, Graptopetalum, etc.

There are several types of leaf cuttings:

Figure 1. LEAF CUTTING - LEAF-PETIOLE

LEAF CUTTING - LEAF-PETIOLE

1. The knife must be very clean, or you risk infecting the leaf. Remove a leaf and include up to 1 1/2 inches of the petiole (The stalk attaching the leaf blade to the stem or crown base). Or carefully pull down and off mother plant. Allow to dry a little to develop a callus bud.
2. Leave the leaf some place protected from sun and kept warm, long enough for a film (callus) to form over the cut part. This can take as little a few days to as long as two weeks, depending on type of plant. This film will help keep the cut part from getting infected by the soil, or rotting.
3. Hold the leaf gently and dip the cut end of the petiole into a rooting hormone.
4. (Figure 1). Insert the petiole of the leaf into an appropriate medium at a 45 degree angle. Since new plants develop at the base of the leaf it is important that the leaf does not shade the new plants or touching anything moist that might cause mold or rot.
5. Keep leafy cuttings soil moist and humid at all times. Don't keep leaves below soil line. Remove fallen leaves and diseased cuttings or parts regularly.
6. Increase the humidity around the cuttings. For a single pot use a clear plastic bag propped up with chopsticks. When using a standard black seedling tray, a clear plastic humidity dome works well. Bottom heat of about 65-75 degrees F should be provided if possible. Keep in a protected area that is like a mini greenhouse or terrarium. I like a covered clear plastic storage bin/container, or you can also use clean recycled clear food containers, like salad boxes.
7. Keep moist by misting often in warm weather and lightly misted in cool weather. Never let dry out.
8. Once the new plants have formed, (Figure 1) in approximately 8 weeks, carefully separate (divide) each new plant from the parent. (Chopsticks or tweezers can be used) Avoid damaging the delicate roots. It is these new plantlets which form around the stem which are used to transplant. The old leaf can be discarded. Sometimes is a mass of clusters of plantlets, so divide carefully.
9. Transplant each new plant into a 2 ½ -4 inch pot, using a lightweight, pre-wetted, potting soil and water thoroughly.
10. I still keep them in a greenhouse like environment in a shady, bright area to help them get stronger, you can also use indoors under grow lights. And then pot up each stage to the size you want. Slowly add diluted fertilizer -I prefer organic houseplant food.

It's a slow process, but I hope you enjoy how new plants are made asexually, and hopefully appreciate their will to survive and the way plants create a way to clone themselves without sexual means.

---------------------------------------------------------------------------------------------------

Figure 2. Take a healthy leaf. Cut the leaf into sections, each with a main vein.

LEAF CUTTING - LEAF WITHOUT A PETIOLE

This method is used for plants with thick, fleshy leaves.

• A monocot, (Monocot seedlings typically have one cotyledon seed-leaf, like a blade of grass) The Mother-in-law or Snake Plant (Sansevieria), and ZZ plant (zamioculcas zamiifolia) can be propagated by cutting the long leaves into 3- to 4-inch pieces. Insert the cuttings vertically into the medium. (Figure 2. see drawing)
• A dicot, (a group of flowering plants whose seed typically has two embryonic leaves or cotyledons as seedlings.) like a African violet, or Begonia it can also be propagated from the leaf blade itself.

Like the last instructions: take a leaf of Mother-in-law-tongue, (Sansevieria) cut a leaf from a plant and remove the petiole. Make sure you keep the tops at a slant and bottom straight. Let it callus, dip in rooting hormone, Insert the leaf vertically into the medium making sure that the midvein is buried in the rooting medium. You can cut many pieces from one leaf blade.

(Figure 2). New plant(s) will form from the midvein. Remember if cuttings are stuck upside down they will not root. Leaf cuttings can be literally crowded together, almost shoulder to shoulder. This crowding will not harm them, and once the root systems have been developed they can be separated for transplanting into individual pots.

Other plants: Some Cactus (particularly varieties producing "pads" like Bunnies Ears), Crassula (Jade Plant), Kalanchoe, Peperomia, Sedum and many other succulents. Some Aloes (Difficult, has too high moisture content),

Figure 3. Split leaf cuts and (2) new plantlets forming

LEAF CUTTING - Split-vein and leaf wedge

I usually use clean, plastic storage boxes like little greenhouses. Begonias especially like high humidity.

Note: Everything needs to be sterile.

1. SPLIT-VEIN, Detach a leaf from a Begonia - rhizome types (Begonia sp.) and remove the petiole. (stem) Make cuts on several prominent veins on the underside of the leaf (Figure 3). Lay the cutting, lower side down, on the medium. If the leaf curls up, hold it in place by covering the margins with rooting medium or staples (Hair bobby pins). New plants will form at each cut in about 6-8 weeks. (This method is more challenging.)
2. LEAF WEDGE, A variation of this method is to cut the leaf into wedges, You can get more plant Letts from one leaf. (Figure 3b) so that each piece has a main vein. The leaf wedge should be inserted into rooting hormone and then into the media with the main vein partially covered. (I prefer this method, it has a better chance of success.)

Figure 3b. Wedge cuts

-----------------------------------------------------------------------------------------------------------

Figure 4. The stem portion produces roots, and a new shoot develops from the bud

LEAF CUTTING - LEAF-BUD CUTTINGS

Leaf-bud cuttings are used for many trailing vines and when cutting material is limited. Each node on a stem can be treated as a cutting. This type of cutting consists of a leaf blade, petiole, and a short piece of stem with an attached axillary bud. Place cuttings in the medium with the bud covered (1/2 to 1 inch) and the leaf exposed (Figure 4). Examples of plants that can be propagated in this manner include: Clematis, camellia, jade plant, rubber plant, grape ivy, dracaena, blackberry, mahonia, and heart-leaf philodendron, English Ivy, pothos, Pelargoniums-Geraniums. Plant material selected for leaf cuttings should be healthy, actively growing and free of insect or disease problems. Large, mature leaves provide the best source of propagation material. THIS IS A SLOWER WAY TO PROPAGATE, BUT YOU GET MORE OF THE SAME KIND OF VARIETY FROM 1 STEM.

--------------------------------------------------------------------------------------------------

(Notes: Many plants will easily root in water. However, the roots that form can be extremely fibrous and stringy. Plants rooted in water often have a difficult time becoming established after they are transplanted into a container.)

CARE DURING AND AFTER ROOTING:

Moisture:

The propagation medium should be thoroughly moistened before use. (SEE PAGE 1)

KEEP SOIL SLIGHTLY MOIST, (like a squeezed out sponge) if too wet, plants will rot. Make sure you have holes in bottom of pot and good drainage.

Misting everyday in warm weather and watering with a soft nozzle till the plants are strong enough to hold up to regular watering.

After you've potted up to next size, you can give them a very low dose of liquid fertilizer, like sea kelp every 2 weeks.

When you get to the 4 inch size you can transplant into good potting soil.

Light:

Light is an important environmental factor in plant propagation. Generally speaking, low light levels cause plants to root slowly. However, too high light intensities can stress cuttings, causing them to burn or drop leaves. Diffused sunlight generally provides enough light for optimum rooting without causing injury to the cuttings. but still bright enough to read a book by.

Humidity:

Since cuttings do not have roots, they cannot replace the water lost through transpiration. Therefore it is important to maintain high humidity around the cuttings to cut down on the amount of moisture lost to the atmosphere.

These conditions can be provided by placing a clear piece of plastic over the propagation area. This causes condensation to form on the underside of the plastic that provides the necessary humidity. Adequate ventilation is also required to avoid disease problems. The plastic covering should be placed such that air can flow freely around the cuttings as they root. If the leaves are touching the sides of the container they may rot.

Temperature:

For best results, maintain day temperatures at 70 degrees F. During winter months, soil can be as much as 10-20 degrees less than air temperature, so provide bottom heat when possible. Ideal rootzone temperatures for most plants are approximately 70-75 degrees F. If the hot sun hits the container it may cook the delicate cuttings or young plants.

ON ROOTING HORMONES (Please follow safety directions on container)

Rooting hormones are often used to promote root formation. These materials provide supplemental auxin, a naturally occurring plant hormone that is responsible for root development. These products kill fungus and bacteria to prevent the stem from rotting, and contain a growth hormone to speed the formation of roots.

The end of the cutting is dipped into the chemical prior to sticking it into the propagation medium. These products come in different strengths and will vary according to the type of plant being propagated.

IMPORTANT: To use rooting hormone, place the amount needed in a separate container. Any material that remains after treating the cuttings should be discarded, not returned to the original container. These precautions will prevent contamination of the entire bottle of rooting hormone. Let the stem set for a minute.

Though some plants will root readily without treatment, application of rooting hormone to the base of the cutting will often improve your chance for success.

BUT there are always exceptions: Pelargoniums - Geraniums, some Roses and Succulents. do much better without root hormone.

Homemade organic rooting hormone

MAKE ROOTING HORMONE WITH WILLOW WATER!

The active ingredient of many commercial rooting products is Indolebutyric Acid (IBA), a natural plant hormone and and Salicylic acid (SA) (which is a chemical similar to Aspirin) is a plant hormone which is involved in signalling a plant’s defences. (Do not use Aspirin, it's too strong and contains too many other chemicals.)

When you make willow water, both salicylic acid and IBA leach into the water, and both have a beneficial effect when used for the propagation of cuttings. One of the biggest threats to newly propagated cuttings is infection by bacteria and fungi. Salicylic acid helps plants to fight off infection, and can thus give cuttings a better chance of survival. Plants, when attacked by infectious agents, often do not produce salicylic acid quickly enough to defend themselves, so providing the acid in water can be particularly beneficial.

1. Collect a handful of young first-year twigs and stems of any of willow (Salix spp.) species, these have green or yellow bark. Don’t use the older growth that has brown or gray bark. Remove all the leaves, these are not used.
2. Take the twigs and cut them up into short pieces around 1" (2.5cm) long.
3. The next step is to add the water. there are several techniques to extract the natural plant rooting hormones:

• Place the chopped willow twigs in a container and cover with boiling water, just like making tea, and allow the “tea” to stand overnight.
• Place the chopped willow twigs in a container and cover with tap water (unheated), and let it soak for several days.

4. When finished, separate the liquid from the twigs by carefully pouring out the liquid, or pouring it through a strainer or sieve. The liquid is now ready to use for rooting cuttings. You can keep the liquid for up to two months if you put it in a jar with a tight fitting lid and keep the liquid in the refrigerator. Remember to label the jar so you and other people know what it is, and write down the date you brewed it up, and to aid the memory, write down the date that it should be used by, which is two months from the date it was made! You can also freeze it for years of use.
5. To use, just pour some willow water into a small jar, and place the cuttings in there like flowers in a vase, and leave them there to soak for several hours so that they take up the plant rooting hormone. Then prepare them as you would when propagating any other cuttings.
6. Now remember since this method isn't very exact, the strength of the willow water can vary depending on the time of year, the number of twigs, the concentration of hormones in the twigs, and the amount of time that the twigs were soaked. You will, however, still get a solution that will help your plants root.

WARNING: Latest FAD on the internet: Cinnamon as rooting agent

I HAVE FOUND MANY UNPROVEN “FACTS” ON THE INTERNET, ONE IS:

• “Cinnamon as a rooting agent is as useful as willow water or hormone rooting powder. A single application to the stem when you plant the cutting will stimulate root growth in almost every plant variety.”. FALSE
• “Give your cuttings a quick start with the help of cinnamon powder. Pour a spoonful onto a paper towel and roll damp stem ends in the cinnamon. Plant the stems in fresh potting soil. The cinnamon will encourage the stem to produce more stems, while helping to prevent the fungus that causes damping-off disease. FALSE

Whether or not the antibacterial properties pertain specifically to real cinnamon or cassia (what's usually in the bottle when you buy cinnamon at most grocery stores) is up in the air. I also found these other claims, remember just because it's on the internet doesn't make it true.

“To promote root growth, create a rooting solution by dissolving an aspirin in water.” or “try mixing 1-3 Tbs of honey per gallon of water” FALSE!

I am trying these as an experiment, but I am VERY sceptical.

GOOD LUCK AND HAVE FUN MAKING NEW PLANTS FROM CUTTINGS, IT'S A GREAT WAY TO GET FREE PLANTS!

by Katarina Eriksson, Horticulturist.

katsflowers@gmail.com

Notes on Grafting

Introduction

Grafting and budding are horticultural techniques used to join parts from two or more plants so that they appear to grow as a single plant. In grafting, the upper part (scion) of one plant grows on the root system (rootstock) of another plant. In the budding process, a bud is taken from one plant and grown on another.

Although budding is considered a modern art and science, grafting is not new. The practice of grafting can be traced back 4,000 years to ancient China and Mesopotamia. As early as 2,000 years ago, people recognized the incompatibility problems that may occur when grafting olives and other fruiting trees.

Since grafting and budding are asexual or vegetative methods of propagation, the new plant that grows from the scion or bud will be exactly like the plant it came from. These methods of plant reproduction are usually chosen because cuttings from the desired plant root poorly (or not at all). Also, these methods give the plant a certain characteristic of the rootstock - for example, hardiness, drought tolerance, or disease resistance. Since both methods require extensive knowledge of nursery crop species and their compatibility, grafting and budding are two techniques that are usually practiced only by more experienced nursery operators.

Most woody nursery plants can be grafted or budded, but both processes are labor intensive and require a great deal of skill. For these reasons they can be expensive and come with no guarantee of success. The nurseryman must therefore see in them a marked advantage over more convenient propagation techniques to justify the time and cost.

Clones or varieties within a species can usually be grafted or budded interchangeably. For example, Pink Sachet dogwood can be budded or grafted onto White Flowering dogwood rootstock and vice versa. Bradford pear can be grafted or budded onto Callery pear rootstock and vice versa. However, Pink Sachet dogwood cannot be grafted or budded onto Callery pear.

Grafting and budding can be performed only at very specific times when weather conditions and the physiological stage of plant growth are both optimum. The timing depends on the species and the technique used. For example, conditions are usually satisfactory in June for budding peaches, but August and early September are the best months to bud dogwoods. Conversely, flowering pears can be grafted while they are dormant (in December and January) or budded during July and August.

Reasons for Grafting and Budding

Budding and grafting may increase the productivity of certain horticultural crops because they make it possible to do the following things:

Change varieties or cultivars. An older established orchard of fruiting trees may become obsolete as newer varieties or cultivars are developed. The newer varieties may offer improved insect or disease resistance, better drought tolerance, or higher yields. As long as the scion is compatible with the rootstock, the older orchard may be top worked using the improved variety or cultivar.

Optimize cross-pollination and pollination. Certain fruit trees are not self-pollinating; they require pollination by a second fruit tree, usually of another variety. This process is known as cross-pollination. Portions of a tree or entire trees may be pollinated with the second variety to ensure fruit set. For example, some hollies are dioecious, meaning that a given plant has either male or female flowers but not both. To ensure good fruit set on the female (pistillate) plant, a male (staminate) plant must be growing nearby. Where this is not possible, the chances that cross-pollination will occur can be increased by grafting a scion from a male plant onto the female plant.

Take advantage of particular rootstocks. Compared to the selected scion, certain rootstocks have superior growth habits, disease and insect resistance, and drought tolerance. For example, when used as rootstock for commercial apple varieties, the French crabapple (Malus sylvestris, Mill.) can increase resistance to crown gall and hairy root. Malling VIII and Malling IX are used as dwarfing rootstocks for apple trees when full-sized trees are not desired, such as in the home garden.

Benefit from interstocks. An interstock can be particularly valuable when the scion and rootstock are incompatible. In such cases, an interstock that is compatible with both rootstock and scion is used. An interstock could increase the disease resistance or cold hardiness of the scion. Plants also may be double worked to impart dwarfness or influence flowering and fruiting of a scion.

Perpetuate clones. Clones of numerous species of conifers cannot be economically reproduced from vegetative cuttings because the percentage of cuttings that root successfully is low. Many can be grafted, however, onto seedling rootstocks. Colorado blue spruce (Picea pungens, Engelm), Koster blue spruce (Picea pungens var. Kosteriana, Henry), and Moerheim spruce (Picea pungens var. Moerheimii, Rujis) are commonly grafted onto Norway spruce (Picea abies, Karst.) or Sitka spruce (Picea sitchensis, Carr.) rootstock to perpetuate desirable clones. Numerous clones of Japanese maple (Acer palmatum, Thunb.) that either root poorly or lack an extensive root system are grafted onto seedling Acer palmatum rootstock.

Produce certain plant forms. Numerous horticultural plants owe their beauty to the fact that they are grafted or budded onto a standard, especially those that have a weeping or cascading form. Examples include weeping hemlock (Tsuga canadensi.3, Carr. var. pendula, Beissn.), which is grafted onto seedling hemlock rootstock (Tsuga canadensis, Carr.); weeping flowering cherry (Prunus subhietella var. pendula, Tanaka), which is grafted onto Mazzard cherry rootstock (Prunus avium, L.); and weeping dogwood (Cornus florida, L. var. pendula, Dipp.), which is grafted onto flowering dogwood rootstock (Cornus florida, L.). In most cases, multiple scions are grafted or budded 3 feet or higher on the main stem of the rootstock. When used this way, the rootstock is referred to as a standard. It may require staking for several years until the standard is large enough to support the cascading or weeping top.

Repair damaged plants. Large trees or specimen plants can be damaged easily at or slightly above the soil line. The damage may be caused by maintenance equipment (such as lawn mowers, trenchers, or construction equipment), or by disease, rodents, or winter storms. The damage can often be repaired by planting several seedlings of the same species around the injured tree and grafting them above the injury. This procedure is referred to as inarching, approach grafting, or bridge grafting.

Increase the growth rate of seedlings. The seedling progeny of many fruit and nut breeding programs, if left to develop naturally, may require 8 to 12 years to become fruitful. However, if these progeny are grafted onto established plants, the time required for them to flower and fruit is reduced dramatically. Another way to increase the growth rate of seedlings is to graft more than one seedling onto a mature plant. Using this procedure as a breeding tool saves time, space, and money.

Index viruses. Many plants carry viruses, although the symptoms may not always be obvious or even visible. The presence or absence of the virus in the suspect plant can be confirmed by grafting scions from the plant onto another plant that is highly susceptible and will display prominent symptoms

When to Graft

Unlike budding, which can be performed before or during the growing season, most grafting is done during winter and early spring while both scion and rootstock are still dormant. Containerized plants may be moved indoors during the actual grafting process; after grafting, these plants are placed in protected areas or in unheated overwintering houses. Field-grown stock, of course, must be grafted in place. Some deciduous trees are commonly grafted as bare rootstock during the winter and stored until spring planting. Indoor winter grafting is often referred to as bench grafting because it is accomplished at a bench.

Selecting and Handling Scion Wood

The best quality scion wood usually comes from shoots grown the previous season. Scions should be severed with sharp, clean shears or knives and placed immediately in moistened burlap or plastic bags. It is good practice during the harvesting of scions and the making of grafts to clean the cutting tools regularly. This may be done by flaming or immersing them in a sterilizing solution. Isopropyl (rubbing) alcohol also works well as a sterilant, although it evaporates quite readily. An alternative sterilizing solution may be prepared by mixing one part household bleach with nine parts water (by volume). However, this bleach solution can be highly corrosive to certain metals.

For best results, harvest only as much scion wood as can be used for grafting during the same day. Select only healthy scion wood that is free from insect, disease, or winter damage. Be sure the stock plants are of good quality, healthy, and true to type. Scion wood that is frozen at harvest often knits more slowly and in lower percentage. If large quantities of scion wood must be harvested at one time, follow these steps:

Cut all scions to a uniform length, keep their basal ends together, and tie them in bundles of known quantity (for example, 50 scions per bundle).

Label them, recording the cultivar, date of harvest, and location of the stock plant.

Wrap the base of the bundles in moistened burlap or sphagnum, place them in polyethylene or waterproof paper bags, and seal the bags.

Store the bundles for short periods, if necessary, either iced down in insulated coolers or in a commercial storage unit at 32° to 34°F.

Never store scions in refrigerated units where fruits or vegetables are currently kept or have been stored recently. Stored fruits and vegetables release ethylene gas, which can cause woody plant buds to abort, making the scions useless.

Keep the scions from freezing during storage.

NOTE: In grafting, as well as budding, the vascular cambium of the scion or bud must be aligned with the vascular cambium of rootstock. In woody plants the cambium is a very thin ribbon of actively dividing cells located just below the bark. The cambium produces conductive tissue for the actively growing plant. This vascular cambium initiates callus tissue at the graft and bud unions in addition to stimulating tissue growth on the basal ends of many vegetative cuttings before they have rooted.

Types of Grafts

Nurserymen can choose from a number of different types of grafts. This section describes only those basic types of grafts used on nursery crop plants.

Cleft Graft

One of the simplest and most popular forms of grafting, cleft grafting, is a method for top working both flowering and fruiting trees (apples, cherries, pears, and peaches) in order to change varieties. Cleft grafting is also used to propagate varieties of camellias that are difficult to root. This type of grafting is usually done during the winter and early spring while both scion and rootstock are still dormant. Cleft grafting may be performed on main stems or on lateral or scaffold branches.

The rootstock used for cleft grafting should range from 1 to 4 inches in diameter and should be straight grained. The scion should be about 1⁄4-inch in diameter, straight, and long enough to have at least three buds. Scions that are between 6 and 8 inches long are usually the easiest to use.

Preparing the Rootstock. The stock should be sawed off with a clean, smooth cut perpendicular to the main axis of the stem to be grafted. Using a clefting tool wedge and a mallet, make a split or "cleft" through the center of the stock and down 2 to 3 inches. Remove the clefting tool wedge and drive the pick end of the tool into the center of the newly made cleft so that the stock can be held open while inserting the scion.

Preparing the Scion. In cleft grafting, one scion is usually inserted at each end of the cleft, so prepare two scions for each graft. Select scions that have three or four good buds. Using a sharp, clean grafting knife, start near the base of the lowest bud and make two opposing smooth-tapered cuts 1 to 2 inches long toward the basal end of the scion. Cut the side with the lowest bud slightly thicker than the opposite side. Be sure the basal end of the scion gradually tapers off along both sides.

Inserting the Scion. Insert a scion on each end of the cleft, with the wider side of the wedge facing outward. The cambium of each scion should contact the cambium of the rootstock.

Securing the Graft. Remove the clefting tool from the cleft so that the rootstock can close. Pressure from the rootstock will hold the scions in place. Thoroughly seal all cut surfaces with grafting wax or grafting paint to keep out water and prevent drying. If both scions in the cleft "take," one will usually grow more rapidly than the other. After the first growing season, choose the stronger scion and prune out the weaker.

NOTE: The temperature of grafting wax is critical. It must be hot enough to flow but not so hot as to kill plant tissue. Recently, paint-like sealants have replaced wax in many areas because they are easier to use and require no heating.

Bark Graft

Bark grafting is used primarily to top work flowering and fruiting trees. In contrast to cleft grafting, this technique can be applied to rootstock of larger diameter (4 to 12 inches) and is done during early spring when the bark slips easily from the wood but before major sap flow. The rootstock is severed with a sharp saw, leaving a clean cut as with cleft grafting.

Preparing the Stock. Start at the cut surface of the rootstock and make a vertical slit through the bark where each scion can be inserted (2 inches long and spaced 1 inch apart).

Preparing the Scion. Since multiple scions are usually inserted around the cut surface of the rootstock, prepare several scions for each graft. Cut the base of each scion to a 11⁄2- to 2-inch tapered wedge on one side only.

Inserting the Scion. Loosen the bark slightly and insert the scion so that the wedge-shaped tapered surface of the scion is against the exposed wood under the flap of bark. Push the scion firmly down into place behind the flap of bark, replace the bark flap, and nail the scion in place by driving one or two wire brads through the bark and scion into the rootstock. Insert a scion every 3 to 4 inches around the cut perimeter of the rootstock.

Securing the Graft. Seal all exposed surfaces with grafting wax or grafting paint. Once the scions have begun to grow, leave only the most vigorous one on each stub; prune out all the others. Bark grafts tend to form weak unions and therefore usually require staking or support during the first few years.

Side-Veneer Graft

At one time the side-veneer graft was a popular technique for grafting varieties of camellias and rhododendrons that are difficult to root. Currently, it is the most popular way to graft conifers, especially those having a compact or dwarf form. Side-veneer grafting is usually done on potted rootstock.

Preparing the Stock. Rootstock is grown in pots the season before grafting, allowed to go dormant, and then stored as with other container nursery stock. After exposure to cold weather for at least six weeks, the rootstock is brought into a cool greenhouse for a few days before grafting takes place to encourage renewed root growth. The plant should not be watered at this time.

Make a shallow downward cut about 3⁄4-inch to 1 inch long at the base of the stem on the potted rootstock to expose a flap of bark with some wood still attached. Make an inward cut at the base so that the flap of bark and wood can be removed from the rootstock.

Preparing the Scion

Choose a scion with a diameter the same as or slightly smaller than the rootstock. Make a sloping cut 3⁄4-inch to 1 inch long at the base of the scion. (Use the bark grafting technique shown in.

Inserting the Scion. Insert the cut surface of the scion against the cut surface of the rootstock. Be certain that the cambia contact each other.

Securing the Graft. Hold the scion in place using a rubber grafting strip, tape, or grafting twine. Seal the entire graft area with warm grafting wax or grafting paint. Remove the rubber or twine shortly after the union has healed. Never allow the binding material to girdle the stem.

Splice Graft

Splice grafting is used to join a scion onto the stem of a rootstock or onto an intact rootpiece. This simple method is usually applied to herbaceous materials that callus or "knit" easily, or it is used on plants with a stem diameter of 1⁄2-inch or less. In splice grafting, both the stock and scion must be of the same diameter.

Preparing the Stock and Scion. Cut off the rootstock using a diagonal cut 3⁄4-inch to 1 inch long. Make the same type of cut at the base of the scion.

Inserting the Scion. Fit the scion to the stock. Wrap this junction securely with a rubber grafting strip or twine.

Securing the Graft. Seal the junction with grafting wax or grafting paint. Water rootstock sparingly until the graft knits. Over watering may cause sap to "drown" the scion. Be sure to remove the twine or strip as soon as the graft has healed.

Whip and Tongue Graft

The whip and tongue technique is most commonly used to graft nursery crops or woody ornamentals. Both the rootstock and scion should be of equal size and preferably no more than 1⁄2-inch in diameter. The technique is similar to splice grafting except that the whip on the rootstock holds the tongue of the scion in place (and vice versa). This leaves both hands free to wrap the joint.

For the whip and tongue graft, make similar cuts on both the stock and scion. These cuts should be made with a single draw of the knife and should have a smooth surface so that the two can develop a good graft union. Up to this point, rootstock and scion are cut the same as for a splice graft.

Preparing the Stock and Scion. Cut off the stock using a diagonal cut. The cut should be four to five times longer than the diameter of the stock to be grafted. Make the same kind of cut at the base of the scion.

Next, place the blade of the knife across the cut end of the stock, halfway between the bark and pith (on the upper part of the cut surface). Use a single knife stroke to draw the blade down at an angle through the wood and pith. Stop at the base of the initial diagonal cut. This second cut must not follow the grain of the wood but should run parallel to the first cut.

Inserting the Scion. Prepare the scion in the same way. Fit the scion into the rootstock so that they interlock whip and tongue. Be certain that the cambia are aligned.

Securing the Graft. Wrap the junction with a grafting strip or twine, and seal it with grafting wax or grafting paint. Never allow the binding material to girdle the stem.

Saddle Graft

Saddle grafting is a relatively easy technique to learn and once mastered can be performed quite rapidly. The stock may be either field-grown or potted. Both rootstock and scion should be the same diameter. For best results, use saddle grafting on dormant stock in mid- to late winter. Stock should not be more than 1 inch in diameter.

Preparing the Stock. Using two opposing upward strokes of the grafting knife, sever the top from the rootstock. The resulting cut should resemble an inverted V, with the surface of the cuts ranging from 1⁄2-inch to 1 inch long.

Preparing the Scion. Now reverse the technique to prepare the base of the scion. These cuts on the rootstock and scion must be the same length and have the same slope so that a maximum amount of cambial tissue will make contact when the two halves are joined.

Inserting the Scion. Place the V-notched scion onto the saddle of the rootstock. If rootstock and scion are the same diameter, cambial alignment is easier; otherwise adjust as needed.

Securing the Graft. Wrap the graft with a grafting twine, tape, or strip, then seal it with grafting wax or grafting paint.

All of the preceding techniques are used to top work horticultural crops for a particular purpose. Occasionally, however, grafting is used to repair injured or diseased plants. Two common techniques available for this purpose are bridge grafting and inarch grafting.

Bridge Graft

Bridge grafting is used to "bridge" a diseased or damaged area of a plant, usually at or near the base of the trunk. Such damage commonly results from contact with grading or lawn maintenance equipment, or it may be caused by rodents, cold temperatures, or disease organisms. The bridge graft provides support as well as a pipeline that allows water and nutrients to move across the damaged area.

Bridge grafts are usually done in early spring just before active plant growth begins. They may be performed any time the bark on the injured plant "slips."

Preparing the Scion. Select scions that are straight and about twice as long as the damaged area to be bridged. Make a 11⁄2- to 2-inch-long tapered cut on the same plane at each end of the scion.

Preparing the Stock. Remove any damaged tissue so the graft is on healthy stems. Cut a flap in the bark on the rootstock the same width as the scion and below the injury to be repaired. Gently fold the flap away from the stock, being careful not to tear the bark flap.

Inserting the Scion. First, insert and secure the scion below the injury; push the scion under the flap with the cut portion of the scion against the wood of the injured stem or trunk. Then go back and insert and secure the scion above the injury following these same steps. Push the scion firmly into place. Pull the flap over the scion and tack it into place as described for bark grafting.

When grafting with young stems that may waver in the wind, insert the scions so that they bow outward slightly. Bridge grafts should be spaced about 3 to 4 inches apart across the damaged area.

Securing the Graft. Secure all graft areas with warm grafting wax or grafting paint. During and after the healing period, remove any buds or shoots that develop on the scions.

Inarch Graft

Inarching, like bridge grafting, is used to bypass or support a damaged or weakened area of a plant stem. Unlike bridge grafting, the scion can be an existing shoot, sucker, or watersprout that is already growing below and extending above the injury. The scion may also be a shoot of the same species as the injured plant growing on its own root system next to the main trunk of the damaged tree. With the inarching technique, the tip of the scion is grafted in above the injury using the same method as for bark or bridge grafting.