Inspecting my scionwood crop

    Today's bright sunshine and cloudless sky provided me with a great opportunity to photograph my pecan scionwood crop (photo at right). I've been harvesting scions from these same trees for over 6 years now and you can easily see how the heavy annual pruning has changed the pattern of pecan tree growth.

    Note the cluster of leaves trapped up in each tree. As leaves fell from the tree last Fall, many of those leaves became lodged in the profusion of branches that sprouted near the pruning cuts I made last season. In a few weeks time, I'll be removing all the one-year-old shoots from these trees allowing all the dead leaves to fall to the ground. After pruning my scionwood trees will look barren and naked.

     However, severe pruning is necessary to stimulate the growth of abundant and vigorous shoots each summer. As you can see in the photo the shoots produced by this method are long, straight, and have large, healthy buds spaced widely apart on the stem. These one-year-old shoots are easy to carve and make strong healthy scions.

     Clicking of "Pecan Scionwood 2024" on the mast head will take you to my pecan scionwood order page. Hopefully, the days of severe drought are behind us and the 2024 grafting season will provide the perfect opportunity to propagate some new pecan trees.

   
 

Cutting pecan scionwood

   

    Last week, the weather was perfect for getting outside and cutting pecan scions. On my farm, I have several trees that are trained specifically to grow high quality scions. The photo at left shows a Yates 68 tree that is covered with long, one-year-old shoots just perfect for making prime scionwood. 

    Depending on the weather, I usually starting cutting scions in late February or early March. The shoots at this time are still fully dormant and the buds are nice and plump.

 

    In the photo at right, I have cut all the one-year-old shoots off the right side of the tree. Note that I deliberately leave short stubs with each pruning cut. This will provide multiple buds for developing new shoots this spring, creating even more scionwood opportunities for 2023.

    Eventually, I prune every shoot off the tree (photo at left). This kind of drastic pruning practically eliminates nut production and retards overall tree growth. However, by limiting height growth, I can maintain a steady supply of easily accessible and healthy scions for years to come. 

     Once I have all the one-year-old shoots on the ground, I pick up the limbs and start cutting them into graft-size pieces. I store my scions is plastic tote boxes that feature tight-fitting lids. Before adding scions to the box, I line the bottom with 4 layers of paper towels. I then pour just enough water on the towels to soak them fully. I cut scions 5 to 7 inches long with each stick having at least 3 buds. I carefully stack the scions in the box making sure not to dislodge buds from the sticks. Once I fill the box, I place another layer of paper towels over the top of the scions and moisten with water. 

    The wet paper towels help to maintain 100% relative humidity inside the box, keeping the wood from drying out in storage. After attaching the lid of the box, I store the scions in a cooler kept at 34 degrees F.   At my location, grafting season starts during the last week of April or early May.

Harvesting pecan scionwood

      All this week, I've been busy cutting pecan scionwood from trees that were specifically trained to produce long one-year-old shoots. The photo at right is just one of several scionwood trees I have growing near my home. Notice the many long, light-colored shoots produced by this tree especially at the top of the canopy. The pruning technique I used to create this rapid shoot growth has an old world name -- pollarding.

    The radical pruning of a tree (pollarding) is an ancient practice use to produce long limber sticks that could be used to weave fences to control grazing livestock, to make baskets or to burn as firewood. The Vincent Van Gogh painting at left depicts a typical rural scene of rows of pollarded trees. Pruning cuts were made above grazing height to prevent cattle, sheep, and goats from feeding on tender new shoots as their emerge in the spring.

 

     I've haven't taken up basket weaving in my retirement, but I still cut all the one-year-old shoots off my scionwood trees reminiscent of my European ancestors (photo at right). Once I get all the shoots to the ground, I then cut the shoots into 7-8 inch long scions.

   Pollarding pecan trees produces excellent scionwood. The shoots are vigorous, have widely spaced buds and have ample stored carbohydrates ensuring maximum graft success.

     As I cut the shoots into scions, I make certain that each stick has strong healthy buds. The photo at left shows the typical primary, secondary, and tertiary buds that can be seen above each leaf scar on a pecan twig. I always make sure to have at least two sets of buds near the top of each scion stick.

  

    The rapid shoot grow associated with pollarding pecan trees often stimulates the production of stalked buds (photo at right).  In preparing my scions, I always prune off stalked buds. These long buds often get broken off during storage and handling. If they remain, they can puncture the plastic bag used to store and ship scions increasing the potential for scionwood desiccation. As you can see in the photo, a strong secondary bud sits just below the stalked bud and will provide a great growing point for a successful graft.

       The photo at left illustrates the quality of scions cut from trees specifically pruned to grow vigorous one-year-old shoots. The larger diameter scions I typically use for 3-flap grafting. I like to use smaller diameter scions for bark grafting. 

    

    

Cutting pecan scions

   Over this past week, I've been outside cutting pecan scionwood in preparation for this Spring's grafting season. The photo at right is a Lakota tree that I pruned heavily during the early spring of 2019. Now, after a year of regrowth, this tree has produced numerous long, straight shoots that will make outstanding scions.  
    It took a while, but I cut off every one-year-old shoot from this tree. Some of the shoots were 5 feet long and much too large in diameter to create good scions. However, cutting the tree back again this year will ensure a good supply of scions for 2021.

   After dropping all the one-year-old shoots to the ground, I gathered them into my utility vehicle (photo at left) and hauled them into the barn to cut the wood into usable scions.  In cutting the wood down to size, I try to create scions with at least 3 buds. Scion diameter  ranges from 1/4 to 5/8 inch. I discard the wood that is either too small or too large in diameter.

    As I cut up the shoots, I place the completed scions in a plastic storage box (photo at right). The bottom of plastic box is lined with dampened paper towel to help maintain 100% humidity inside the box during refrigerated storage. Once I fill the box with scions, I cover the wood with another layer of moist paper towels before snapping the lid on tight. I store my scions at 34 degrees F in a refrigerator. Every couple of weeks, I check the paper towel to make sure it is still moist so the wood doesn't dry out during storage.

    If you look carefully at the Lakota tree pictured at left, you will note that I left a 2-3 bud stub at each location I cut a one-year-old shoot. I did this to help promote the growth of 2 or 3 new shoots to replace the one shoot I removed. This should help create even more scions for the 2021 growing season.

Still cutting pecan scionwood

    The month of March sure came in like a lion. On the morning of March 4th, we recorded the coldest temperature for the 2018-2019 winter; 7 degrees F (-14 C). So when things warmed up a little this past weekend, I went out to the pecan grove to check on twig health. Since my trees have remained fully dormant all winter the cambium under the bark was still bright green (photo above). Since the trees are still dormant and the wood is still in good shape, I took advantage of some better weather to cut even more scions.
     I had already cut all the scions I could reach from the ground while pruning my young trees, but this past weekend I needed to get up high into some more mature trees to collect wood from some of the trees in my pecan breeding block. Collecting wood from mature trees is usually a challenge because shoot growth is usually short and buds are close together (close buds make carving a scion more difficult).

     Up in the tree, I spotted what looked like nice long shoots--perfect for scionwood (photo at left). This tree happens to be a cross between Major and Pawnee. Note that even in early March the shoot is still hanging on to a few rachii from last summer's leaves. This is a characteristic inherited from its Pawnee parent.

    On closer inspection, I noted that these long shoots were actually a combination of both 2-year-old and 1-year-old growth (photo at right). Note that only the 1-year-old portion of the stem has large prominent buds. In contrast, all of the primary buds on the 2-year-old wood have aborted from the stem.
      Because of healthy large buds, I usually collect only 1-year-old wood for scions but in this case, the short shoot growth found on this heavily bearing and mature pecan tree is just not well suited for grafting.

     To gain a scion I can easily graft, I cut a scion that is part 1-year-old wood and part 2-year-old wood. I start by cutting the shoot off the tree at a point about 3.5 inches below the beginning of the 1-year-old wood. (photo at left). The presence of healthy buds on the lower portion of the scion is not important to graft success. This is the part of the scionwood stick that will receive all my cuts during the grafting process. For me, its important to harvest a scion that is at least 3/8 inch in diameter and contain more wood than pith inside the stick.  I've found that thin, pithy scions have a high failure rate.
    To complete this scion, I remove the upper portion of the 1-year-old wood. Note that I'll still have some nice plump buds to provide growing points for the graft.  In the end, I only harvested a single scion from each shoot. The scions are about 7 inches long in total and are exactly one half 2-year-old wood and one half 1-year-old wood.
    Although I much prefer collecting scions from young vigorously growing trees, some times you have to just make things work.  

Cutting pecan scionwood

     Folks often ask me when is the best time for cutting pecan scionwood. Yesterday, while cutting my own scions, the answer presented itself. A large flock of honking geese flew overhead on their way back north. It jogged my memory of previous years of scionwood collection and I realized that the spring migration of geese always coincides with the perfect time to cut scionwood.

   Earlier this week, we had some good weather for working outside and I cut scions for all the grafting I have planned for 2019. I started by attacking a young grafted tree that had grown a lot of strong vigorous shoots the previous season (photo at right). Most one-year-old shoots on this tree were 2 to 3 feet long.

     Looking at the top of the tree, I noticed that three shoots were competing to be the primary central leader (photo at left). In harvesting scions from this tree, I could not only get some great scions but I could train the tree back to a central leader.

    I cut almost every one-year-old shoot off this tree which yielded a good collection of twigs that could be cut into scions (photo at right). At this point in this young tree's life, I'm not concerned about cutting off all potential nut producing shoots. This tree is so small that any nut production at this stage would be minimal.

    I like to store my scionwood cut into pieces appropriate for making a single 3-flap or bark graft. When cutting the wood, I always make sure to pay attention to the location of buds near the top of the stick. I cut the wood about 1/2 inch above the upper-most bud, then make sure I have a second bud within the upper half of the stick (photo at left). I don't worry about buds on the lower half of the stick because they will be removed during the grafting process.

    While cutting up scions, I also look for stalked buds (photo at right). These type of buds do not prevent a graft from taking but they are a problem during scion storage. Stalked buds tend to puncture plastic storage bags increasing the risk of scion desiccation during refrigerated storage.

     You should note a strong secondary bud just below each stalked bud. I carefully snip off the stalked bud making sure not to injure the secondary bud (photo at left). Only after this detailed pruning is complete do I place the scion in a storage bag.

   

    A single long shoot can produce several scionwood pieces. The photo at right shows a typical one-year-old shoot harvested from a young tree.

    When cut into graft sized pieces, I was able to get six scions (photo at left). These sticks are arranged in the older they were cut from the shoot pictured above. The larger diameter scions are perfect for 3-flap grafts while the small diameter wood is better sized for bark grafting. I discarded the terminal piece.

 
 The photo above shows how I harvested the scionwood from a young tree. Note that I left a single shoot at the top of the tree to become a central leader. All other shoots were stubbed back. Next spring, this tree will sprout new shoots from two-year-old wood and fill out its canopy.

    I don't always butcher my trees to collect scionwood. Many times, I'll collect wood from the pruning cuts I make at this time of year. The tree pictured at right is a prime example. This tree has formed two central leaders connected by a narrow fork in the trunk. I should have spotted this problem a couple of years ago but I'll take this opportunity to correct the problem now and collect some scions.

     Just one cut with the chainsaw and I recreated a central leader tree (photo above). Yes, I see the branch fork at the very top of the tree. I didn't have my pole pruner on hand, so that cut will have to wait.

   Once I had the pruned-off portion of the tree on the ground, I  noted the numerous shoots that could be harvested for scions (photo at left). Again, young trees seem to produce nice long on-year-old shoots.

    With just one pruning cut, I was able to harvest a whole pile of scions (photo at right). Since the harvested scions range in diameter, I'll be able to find the perfect sized piece when it comes to matching scion to stock at grafting time. 
    I discussed proper scion storage in my previous post HERE.

Trimming trees and collecting pecan scionwood

   Yesterday was a great day to be outside. Good weather days have been rare this winter, so I took full advantage and starting trimming trees and collecting pecan scionwood. The young Kanza tree pictured at right needs a little corrective pruning. First, its time to remove the lowest limb (red arrow). But I also noticed that the tree looks like it trying to develop two central leaders (branches in yellow circle). This is a common problem in Kansas where south facing limbs seem to be blown back into the tree (and into an upright position) by strong winds that blow out of the south all summer long. I'll need attack this problem before a forked tree develops.

    I'll start with the low limb. I'm pruning this limb off simply to make working around the tree easier and to ensure I have plenty of clear trunk to attach my trunk shaker at harvest. The series of photos above shows the process I used to remove the limb. This low limb actually forked close to the trunk so I needed to make 3 cuts to safely remove it from the tree. In photo A, the yellow arrow points to a crease in the bark that indicates where this limb is attached to the trunk. This is also the point where the limb should be removed. However, the forked structure of the side limb made it hard to get my chainsaw into proper position to make the cut. So in photo B, I removed the forked limbs. Now I had a clear shot at cutting the rest of the limb off back to the trunk (photo C).

    I then turned my attention to correcting the dueling central leaders.  The photo at left shows the two branches that are competing for role of central leader. I looked over the crotch where these two limbs diverge and noted a good strong branch connection. This lead me to simply cut back one of the two leaders rather than remove it entirely. I decide to cut back the south facing leader to an outward growing side branch.  In the long run, I'll remove this entire branch because it arises only six feet up the trunk but for the next several years, I'll get some nut production from this limb.

    Removing the upward growing portion of the competing leader (pointed out by blue arrow in photo A above) is two step process.  Since I was holding the chainsaw at head height, I decided to make a quick cut to remove most of the branches weight (photo B). This way I was sure not to drop the limb on myself. I then came back to make a cut just above the point where a side limb grows outwards (photo C).

     Once I had the competing central leader on the ground I noticed several nice long shoots that would make excellent scionwood. These shoots were originally growing at the very top of the tree which is always the best place to find good scions. I used my shears to remove last years new growth (photo above).

    In collecting scionwood, make sure to cut only the wood that grew last year. The photo above will help you identify one-year-old wood over two-year-old wood. Right in the center of the shoot note a darkened ring around the stem. To the left is one-year-old wood with its large plump buds. To the right of the ring, note that the buds have aborted from the two-year-old wood. For grafting pecans, its best to have the healthy buds found on one-year-old shoots.

    You can find one-year-old shoots at the terminals of all shoots. However, side limbs and nut bearing limbs often produce only short shoots with so many buds close together that it makes difficult wood for grafting (photo at left).

   

    From trimming just one Kanza tree I collected numerous long shoots (photo at right). From these shoots, I can harvest several good scions.

     I find the best scions are cut from the basal portion of a long shoot. The photos above demonstrate how I cut scions. Starting with a 2 foot long shoot, I cut 7-8 inch long scions making sure that I create nice straight scion with at least 2 buds near the top of the stick. From this shoot, I cut two scions. I discarded the top of the shoot because it was too small in diameter (small wood has poor graft success).

    When cutting scions, I am always thinking about how to making the grafting process easier. The shoot above has a pronounced curve in the lower portion of the stem. Rather that trying to carve a crooked scion at grafting time, I cut off the curve and the cut a nice straight scion directly above the curve (photos above).

    After pruning trees for several hours, I brought my scions up to the house to prepare the wood for refrigerator storage. I use one gallon freezer bag to store the wood and paper towels to provide high humidity inside the bag (photo at left).

    Before placing the wood in the bag, I mark the bag with the cultivar name and insert wet paper towels. I used 4 paper towels that were completely soaked with water then squeezed to remove any free water.  Scions are live plant tissue and the high humidity created by the damp paper towels help to keep the wood fresh until the spring grafting season.
 

    To help further prevent moisture loss during storage, I'll place several gallon bags of scions in a plastic storage box clearly marked with the cultivar name. I like to use plastic boxes with the locking lids--they seem to seal better (photo at left).
   I store the wood at 34 degrees F (1 degree C). In storing scions, make sure you do not store them in the same refrigerator as apples. Apples produce the ripening hormone, ethylene, that can cause the buds the abort from your scions. Freezing pecan scionwood will also damage the wood, which is why I purchased a small thermometer to make sure I had the correct temperature setting for my fridge.

Thinning trees and cutting scionwood

    Today, we started cutting down trees in our block of Kanza trees to complete our orchard thinning plan (photo at right). Because Kanza is such a popular cultivar for northern pecan growers, we took advantage of having trees on the ground to cut scions from the long shoots that are usually found only at the very tops of the canopy.

    After setting down the chainsaw, I walked over to the tree's canopy in search of great scionwood. Most of the shoots on the lower portion of the tree's canopy had limited one-year-old growth (photo at left). These 6 to 8 inch long shoots might be great for setting a crop of nuts but they are too small to make good scions.

    The one-year-old shoots at the very top of the tree were 2 to 3 feet in length, had plenty of buds, and were 1/2 to 5/8 inch in diameter (photo at right). These shoots make great scions.

    The photo at left shows you where I cut the one-year-old shoot from the tree.  To the right of the clippers, note the large prominent buds on last year's wood. To the left of the clippers, the two-year-old wood has lost all its primary buds and making it a poor choice for scionwood.

  We cut our scions 7 to 8 inch long and place them in a plastic container (photo at right). Before adding scions to the box, we place a bed of paper towels at the bottom of the container. Once the box is full of scions, we cover the wood with several more sheets of paper towel. Before storing the wood in a cooler, we pour  cup of water over the paper towels to add moisture to the container. The paper towels above and below the scions absorb the water, then act as a wick to keep the air inside the box at 100% relative humidity.  Coupled with storage at 36 degrees F, the plastic boxes and wet paper towels will keep the scion fresh until grafting time.