Contents:

Sexual Propagation
Asexual Propagation
Grafting Techniques
Whip/Cleft Grafting
T-Budding
Chip Budding

Plants have two modes of propagation: sexual and asexual

Sexual Propagation describes when male genes (pollen grain) unite with female genes (ovules) to form seed. There are two ways that this occurs:

Pollen grain are transferred from the male flower part (stamen) to female flower part (stigma), which leads to pollination. The pollen grain then grows a tubule down through the stigma to the ovary, and sends male genes into ovary to unite with female genes in ovules, fertilizing it. The ovary then develops into a fruit, with the ovules becoming individual seeds. Mature fruit falls to ground, and seeds overwinter on or in the soil. In spring, the seeds germinate and seedlings appear.

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Asexual Propagation: is cloning. Offspring are genetically and physically identical to their parent plant.

Methods:

  1. Division
    • Crown division – the crown is the region where the roots join the stem(s). In fall, you can cut the crown longitudinally into several sections, each containing both stem and root, and plant them immediately or overwinter them in a root cellar until spring (rhubarb).
    • Root division – in fall, after dieback, divide the root system into chunks, each containing several dormant underground buds (which will develop into next year's shoots), and plant immediately. The new plants will require at least a year to mature.
    • Suckers – the shoots that sprout along underground stems (runners) some distance from original crown will eventually develop into whole new plant (raspberries).
    • Stolons – these above ground runners root periodically, producing a whole new plant (strawberries).
    • Tip rooting – the tip of a stem contacts the ground and sprouts roots, developing into new plant (blackberries).
  2. Layering – generating new plants by making plants sprout roots along the stems.
    • Simple layering – this works best with woody shrubs with flexible stems. In spring, bend the stem to the ground until it contacts the soil just behind the tip, cover it with soil behind the tip, and wait a full year before severing the stem from parent plant. It can help to notch the underside of the stem where it contacts ground (black raspberries, blueberries, currants, grapes).
    • Compound layering – this is like simple layering, but cover a trailing stem with soil at several points/nodes along its length (grapes).
    • Mound layering (stooling) – with woody, inflexible/breakable stems, notch the base of each stem, mound soil around base of the plant so that notches are well covered, and wait l-2 years before severing the rooted stems from the parent plant (blueberries, currants, gooseberries, hazelnut shrubs, juneberries).
    • Air layering – in mid spring, ring or girdle a branch in the area of last year's growth, surround it in a moist substance (such as compost surrounded in moss), wrap it in plastic, then wait 1 growing season before severing the branch between parent and plant.
  3. Cuttings - generating whole new plants from cut pieces of stem or root:
    • Stem cuttings (hardwood) – after fall dormancy and before spring bud-break, cut 6-12” pieces of the most recent season's growth, and store at 50-55 degrees Fahrenheit for 2 months (this simulates the first half of winter) to induce callus formation (the tissue from which roots can development). Then store at 35-40 degrees Fahrenheit for 2 months (this simulates the second half of winter) to slow growth until spring and facilitate bud break. Pot them in spring, and tent them in plastic to prevent desiccation until the roots develop (grapes, currants, filberts, gooseberries, mulberries).
    • Root cuttings – in fall after dormancy, cut roots of pencil thickness into 3-4” sections. Overwinter them as described for stem cuttings and plant them in spring (blackberries).
  4. Grafting – creating a new plant by joining a scion or bud from a variety with desirable fruit, flowers, leaves, and/or bark to the roots of a variety with desirable growth characteristics. This is done with a scion or bud. The graft is successful ('takes') when the cambium layers/vascular systems of the two varieties join.
    • Scion: a 4-8” stem cutting (2-5 buds) used to graft. Note: “Water sprouts” are not good scions for either whip or bud grafting.
    • Rootstock: a 2-3 year old seedling, lopped off l-2” above ground level, affords hardiness to specific soil and weather conditions, and pest/disease resistance, also influences the scion's growth potential (dwarfing, in some cases).

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Grafting Techniques:

Simple Whip Grafting

Whip, splice, or cleft grafting is a simple technique for propagating apples, pears, and to a lesser extent, other fruits and nuts. Several items are required: rootstock, scionwood (preferably of the same diameter) sharp grafting knife, rubber strips, and water proof tree dressing (wax base or tree heal). Timing is important, the ideal time to graft is mid to rate spring when the sap is flowing well, apple trees in your area are in full bloom, and night time temperatures don't go below freezing. The scionwood to be grafted should have been cut previously and fully dormant. The over-riding principle of grafting is to match cambium surfaces, that part of the tree just under the bark that is the tree's bloodstream, try to maximize the contact of this area between the rootstock and the scionwood. Before use, scionwood should be refrigerated with moist packing (paper towels, or newspaper) in a plastic bag.

Step 1
Find the part of the rootstock trunk that is the same diameter is the scion. Given a choice, partial cambial contact lower on the stem (say, 4" to 12"), is better than full contact higher on the stem (say 2' to 3'). Clean off the branchlets in the area. For a whip graft, use a sharp grafting knife to cut upward through the rootstock with a sloping, flat cut, Longer is better, about 1 1/2" is usually fine. For a cleft graft, cut across the rootstock, then split it 1-1½” down, as shown in the figure. Do not touch the cut surface and work quickly, but safely!

Step 2
Cut your scion to complement the rootstock. For a whip graft, use a cut identical to the one used on the rootstcok, and of identical length. For a cleft graft, cut the scion on both sides to make a wedge about 1¼” long. The scion should have 2 to 3 buds on it. Examine both the scion and the stock next to one another to be sure they will match. Place the scion on the stock (or, in the case of cleft grafting, fit it into the split in the stock) and gently, but firmly, wrap the union with a long rubber strip. A good guide on tightness is that the rubber strip should never be stretched out so that it is less than 1/2 the unstretched width. Tuck the end of the strip under the last wrap. Check again the alignment of cambial layers.

Step 3
Paint the top cut end of the scion with dressing. Cover the entire graft union area with dressing to prevent drying out. We use grafting bags, held at the bottom with rubber strips. This acts like a miniature greenhouse, callusing more quickly. Removal of this bag should be in approximately two weeks. Checking first to see if you have good bud growth. You now have a graft. Care for your new trees following the procedures in the next section.

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T-Budding

T-budding is a form of grafting useful for all the common fruit trees and many nuts. It uses the same materials as whip grafting but at a different time of the year. The best time for budding is late August in northern areas when the rootstock is still vigorously growing, but the wood has hardened slightly and the scion buds at the base of the leaf stems are full sized, mature and plump. Stocks for budding may be set out the previous spring and cut back to the ground, to encourage a single vigorous shoot to receive the bud. Larger trees can also be topworked by budding and buds are always best placed on the current years growth. Fresh cut scions are important, as soon as the twigs (use the middle 2/3 of current years growth) are cut, the leaf blade should be cut off, leaving the leaf stem as a handle. These scions should be carried with the cut ends in water, and kept out of the sun, perhaps in a cooler.

Step 1
Prepare the stock by stripping off the leaves in the area where the bud will be inserted. Lower is usually always better, 4” above ground level on t year whips. Cut into the south side of the tree with a short horizontal cut, make a downward vertical cut for 1 1/4” or so, just through the bark. This is the “T” shape that gives this the common name of T-budding. Use the budding nose or bud opener blade on your knife to lift the 2 side flaps of the bark away from the wood.

Step 2
Remove the bud from the bud stick by inserting the knife about 3/4” below the bud and, cutting just deep enough to remove a sliver of wood below the bud, draw it under the bud to about 3/4” above the bud. Remove the bud by its leaf stem, with a straight cut across the top end of the bud shield. Keep your fingers and dirt off the cut surfaces!

Step 3
Insert the bud shield into the top of the T, opening the bark flaps of the rootstock, pushing down firmly. Cut off the upper end of the bud shield, in line with the horizontal cut, or top of the T, on the stock. Clean sharp cuts are important in all these operations.

Step 4
Wrap the bark and bud with a rubber strip, somewhat more loosely than described in the grafting section. Do not cover the bud or leaf stem; the latter will quickly fall off in a week or so, indicating successful union. In dry or hot conditions, it is useful to paint on a dressing to prevent drying out. Here we use saran wrap, to go completely around then rubber strips both top and bottom, acting like a miniature green house, callusing more quickly. If it is not a take, you will find the top or bottom of the inserted bud starting to pull away (drying out). The dormant bud stays healed in through the winter.

Step 5
The following spring, just as the buds begin to shoot, cut off the rootstock l/4” above the bud union. Use a bamboo stake to tie the new bud shoot, when it reaches 6” or better in height, to help in training and prevent dislocation in the wind.

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Chip Budding

Chip budding is now becoming the normal procedure used most widely in the fruit tree propagation field today. This procedure is used almost exclusively by propagation experts for 2 main reasons, (1) it is faster and easier to do than T-budding and (2) in times of variable weather, or plant growth conditions at budding time, it tends to be more successful than T budding. T-budding is still important when there is a mismatch in size between budwood and rootstock, and for the novice (seems more the case as compared to a professionals view point), therefore, this procedure should still be encouraged when it “feels” or “looks like” the more comfortable approach to getting the job done. At Bear Creek we use both procedures when one or the other budding process looks like it will work best. The most important facet of chip budding is that the bud stick matches in caliper the part of the rootstock where the bud is to be placed. If the match is there between the two, then you will know you can chip bud as opposed to placing a T-bud.

Step 1
Prepare the Rootstock as you would for T-budding by stripping off the leaves in the area where the bud will be inserted.

Step 2
Cut the bud chip from your budwood stick, Do this by inserting the knife 1/2” above the bud and cutting in a downward stroke under the bud to a point 1/4" below the bud, but not completely out of the stock' To remove the bud chip, now take Your knife and cut under the bud in a slight downward angle (a dove tail cut), into the stem, matching up with your first cut. Remove the bud chip. Most folks hold it between their teeth by the leaf stem base to prevent contamination.

Step 3
Using the bud stick with the chip removed as a pattern, (some folks lay it next to the rootstock, others hold it along side the rootstock between several fingers), cut a matching chip of wood from the rootstock. Compare the notch cut on the bud stick to the notch cut on the rootstock to see that they match. If your rootstock notch is smaller, (you should always cut to favor the small size), you can whittle on it with your knife to size it up to match.

Step 4
Insert your bud chip into the notch on the rootstock. The dovetail section is the most important part of the “match”, as it creates the solid seat for the bud chip to sit firmly in place.

Step 5
Wrap the bud chip firmly but not too tight, with a rubber strip leaving the bud or leaf stem itself uncovered. Follow up with a “greenhouse wrap” of saran wrap or parafilm chip budding tape to help hold in the moisture and warmth to assist the callusing Process. A good dose of irrigation to provide a good final boost to the growing process and you should have a completely “healed in” bud chip, prepared to go through the winter comfortably. Parafilm chip budding tape along with the budding rubber will break down and fall off on their own. Any other type of wrappings you will need to remove yourself before winter.

Step 6
The following spring, as you would with a T-budded rootstock, just as the buds begin to shoot, cut off the rootstock just above any or all callusing of the bud union. Also plan to stake the new shoot when it reaches about 6” high to help train it and prevent wind breakage.

Reprinted and adapted with permission from The Bear Creek Nursery Catalogue, published by Bear Creek Nursery, which is no longer in business.

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