HOW TO HARVEST AND STORE SCION WOOD FOR PROPAGATION

WHAT IS SCION WOOD

Scion wood (also called scion) is a young branch cutting from a tree that is used to propagate a plant variety through grafting. Grafting is a technique that joins the tissues of two or more plants together so they become a single plant. This allows growers to combine the desired fruit traits of one variety with the desired properties of a rootstock. There are multiple forms of grafting, including bench grafting, topworking, and bud grafting.

Most fruit varieties have a backstory. At one time, someone bit into that fruit and decided they wanted to replicate that taste or other characteristics of the fruit. Most fruiting plants do not come true to seed (with some exceptions including peaches, pawpaws, and some citrus). In other words, fruiting plants grown from seed tend to be quite variable in their characteristics and do not retain taste, size, disease resistance, or other characteristics of the parent plant. For most common fruits, growing from seed is not a viable means to propagate good quality fruit. For this reason, vegetative propagation like grafting in necessary to ensure desired traits. All named varieties and cultivars of fruits are vegetatively propagated via grafting or rooted cuttings.

Thus the importance of scion wood! In order to get a consistent, high quality fruit with desirable characteristics, scion wood can be used for grafting and propagation of that specific variety with those traits. So how do you collect scion wood for propagation?

SCION SELECTION

Collect scion wood from varieties that appear strong and healthy. Make sure to consider that variety’s fruit quality, taste, pest resistance, cold hardiness, etc. You’re going to want to collect scion wood from varieties with traits you find desirable, often related to the fruit it produces.

Trees younger than 8-10 years old are ideal for collecting scion wood, although newer growth from older trees also works well. The scion wood itself should be first year wood (meaning one year old wood or last year’s growth). How do you find first year growth? A branch is youngest at its ends and gets older down the branch towards its base. Follow a branch tip down until you find a growth scar, which often appear as a cluster of little rings on the wood, and anything below the growth star is one year older. First year wood also tends to be smoother and brighter in color. The scion wood should be ideally at least a pencil’s thickness, at least a foot long, relatively straight, and with plenty of vegetative buds.

Ensure there are no fruiting buds or fruiting spurs. This is especially important because a grafted scion that blooms flowers that first year will divert energy from the necessary vegetative growth it needs in its early stages and can hinder or kill the graft. Luckily most first year wood, the kind of wood you would be using for scion wood, only has vegetative buds on it anyways (with the exception of peaches and some plums). Also avoid selecting water sprouts (vigorous, vertical first year wood that grows from dormant buds) as scion wood, since this is lower quality wood that is less likely to be successful.

If you don’t have access to any trees for scion collection, you can always order scion wood and rootstocks online from edible plant nurseries (see POP’s list of recommended sources).

HOW TO COLLECT SCION WOOD

Make sure to do collect scion wood from fully dormant trees in the wintertime (January through February is ideal). This timing matches nicely with winter pruning season; you’ll be completing two tasks at once! Make sure to sterilize your tools (ideally use bypass pruners). Select healthy-looking first year growth at a pencil’s thickness and at least a foot long with plenty of vegetative buds. Take multiple cuttings since not every graft will be successful, especially for beginners. Cut the ends of the scion wood: a slanted cut 1/4 inch above a bud at the top and a straight cut at the bottom above a bud.

SCION STORAGE

Bundle pieces of scion wood, wrap the bundle in wet paper towel, and place in a sealed plastic bag. Label the bag with the species and variety/cultivar. Store the plastic bag in a cold room with temperatures between 34 and 45 degrees F. Keep out of the sun. Never store in a freezer.  Scion wood can be stored for up to 3-4 months, as long as it is in a proper environment.

WHAT TO DO WITH SCION?

The best time to start grafting with your scion wood is in late winter when trees are still dormant. In Philadelphia, ideal timing tends to be mid March.

IMPORTANCE OF COLLECTING SCION WOOD

There are some important ecological conservation and cultural preservation projects that use scion wood collection to conserve and preserve certain struggling species underway that illustrate why scion wood collection can serve a bigger purpose.

American Chestnut Breeding Program

A big one currently is an effort to bring back American chestnut, which used to reign supreme in the northeast but mostly died out from chestnut blight, non-native fungal disease introduced in New York city in the 1900’s. By the 1950’s, the blight had killed off most of the American chestnuts in their native range (east of the Mississippi). Today, large, wild American chestnut trees are rare in their native range. However, they exist in pockets in the blight-free West largely due to settlers planting them in the 19th century. The American Chestnut Foundation is attempting to conserve the genetic diversity of unique and underrepresented populations of American chestnut through grafting. They are seeking scion wood from wild American chestnut trees from the southern population, which are the most genetically diverse population. One of their main goals is to find a genetic variant of the American chestnut that can survive the chestnut blight. The efforts to bring back the American chestnut are multi-pronged and involve breeding, biocontrol, and bioengineering.

Heritage Apples

Additionally, there are many heirloom varieties that have historic importance and can only continue on via grafting. There are countless historic apple orchards that carry the torch for the preservation of heirloom varieties. The Frank L. Harrington Orchard in Massachusetts preserves a historic collection of 119 heirloom apples. This collection got its start during the Great Depression. These heirloom varieties have been passed down over many generations and are valued for their diversity of taste, color, texture, and size. Since apple seeds are not viable for propagation, harvesting the scion wood from the actual trees are the only way to preserve the genetic material that makes these varieties so cherished. Losing these varieties means losing a piece of history and also any desirable genetic traits. This just points to the important role that scion wood can play in conservation and preservation.

CONCLUSION

The practice of collecting scion wood is a way to preserve and committed to preserving and sharing these varieties for generations to come!

SOURCES

COLLECTING-AND-STORING-SCION-WOOD

New England Botanic Garden at Tower Hill’s apple orchard ready for its next chapter – New England Botanic Garden at Tower Hill

The American Chestnut Foundation | Rooted in Restoration

Fruit Tree Propagation: Grafting – Philadelphia Orchard Project

The Lost Art of Topworking – Philadelphia Orchard Project

The Simple Art of Grafting Fruit Trees: A Complete Guide

This POP Blog was written by Orchard Assistant Simone Shemshedini with help from Co-Executive Director Phil Forsyth.

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