Tuesday, 20 January 2009

Grafting fruit trees

by: Matron of Husbandry
Throwback at Trapper Creek

Want to increase your fruit tree varieties? Try grafting, an age old skill that is fun and economical. This post is a re-hash of a grafting post I wrote last spring. Only this one is a little more timely so you can try your hand at grafting this spring.

Now is the time to be gathering your scion wood while it is still dormant. These photos show apple tree grafting, but I will stay with basic instructions that will work for most types of fruit.

What you are looking for in scion wood is, one year old wood, or last years growth. Probably the most important thing for me to share here is, sharpen your pruners. Most information I see in print, or on the internet about sharpening recommends once or twice a year, that is for pruning not propagating. Death vs. Life. For propagation to be successful, the cambium layers on your scion wood should not be damaged. I used to propagate dwarf conifers for wholesale nurseries and I sharpened my pruners each day that I pruned for cuttings. My pay depended on a successful outcome. I use Felco pruners and they are easy to take apart and service.

Old heirloom trees will have their newer growth at the top (usually out of reach) so you may need a pole pruner too. If you have young trees, the last years growth that you seek will be close at hand.

I cut off more than I need and leave the twigs whole. Label and mark your scion wood with: who, what, where, and when. If you are trying to save an old variety this information will be important, also if your graft doesn't work out, some of this info. may lead you to the cause of the failure. But, also, grafting needn't be only for named varieties, you may have a favorite apple that you covet, but the tree is unmarked. Go for it, if it is a good apple, it is worth propagating.

After labeling, wrap with paper towels, and seal in plastic bags, and refrigerate or heel in, in a pile of deep sawdust, or dirt. The goal is to keep the scion wood dormant and not let it sweat and mold, OR dry out.

The wood on the left of the growth ring is one year wood, suitable for grafting. The wood on the right is too old and tough to make a succesful graft with.

Now besides gathering your scion wood, you need to be purchasing rootstock for your new trees. Size matters..., there are many different rootstocks to choose from. This is a personal preference. I have used both standard and semi-dwarf, and now years later I wish I had used all standard. There are trade-offs to both, standards grow very large, take a long time to bear and are harder to harvest, but they are long lived, and work well with livestock. Semi-dwarf and dwarf, bear early, are easy to harvest but may not last your lifetime due to poor root systems. All my semi-dwarf trees are uprooting and needing more mainentance, my young standards are coltish but not uprooting. Our home orchard here on the farmstead was planted in 1881 as part of the proving up. The trees that have survived that time span, still bear (weather permitting) more than we need. I want my grafted trees to be here for my grandkids!

If you do purchase rootstock, when it arrives, plant it in large nursery pots or in a nursery bed in your garden where the young trees can stay for a year. The grafts need to be protected from intense summer sun, so plan accordingly. If you have a lath house for shade plants this would be ideal. I use pots and place them under a tree, near a hose, so I can easily monitor them and water if needed.

Another option is reworking some existing trees you may already have. If space is your concern, this may be the best option. We have all seen the 3-in-1 trees advertised. Now you can make your own. The only criteria is you have to match scion wood diameter to the limb you're grafting on. No apples and oranges either - only the same types of fruit can be on the same tree.

An old timer taught me this skill, and his best tip was to graft when the rootstock had broke dormancy, and the leaves were the size of mouse ears. Easy to remember, and what he really meant was make sure the sap is flowing enough to make your graft successful.

He also instructed me to save prunings from my apple trees for practicing my cuts. Like a good pie crust, you want to make short work of it. Optimum is two cuts for your apical wedge, one on each side of the scion wood. This requires a sharp knife and practice. Professional grafters get good at this because they are grafting many trees, it is harder when you do a handful a year. I'm lucky to do it in 3 or 4, but my grafts still turn out OK.

When the big day (mouse ears) arrives you will need the following:

  1. Dormant scion wood
  2. Pushing rootstock
  3. Sharp pruners
  4. Sharp knife
  5. Tree labels and a Sharpie
  6. Polyethylene tape (tree tape)
  7. Nerves of steel (just kidding)

Close-up of cutting the apical wedge. Start about 1/2" up the stem and make a downward cut, like sharpening a pencil with your pocket knife. Yeah, that is how I usually sharpen my pencils, that are outside.

Turn the scion wood over and do the same on the other side. Lay your scion wood on a clean surface and prepare the rootstock.

Cut the rootstock horizontally, matching the size of the rootstock to the scion wood. Next make a vertical cut/split about 1" down the rootstock.

Gently push the scion wood down into the rootstock cut. Match the cambium as close as possible. Cut the scion wood down to 2 - 3 buds. Note: in this photo the layers are NOT lined up yet.

Keeping the cambium layers aligned is important and the most difficult part of the graft. If they don't touch, the sap can't bridge the gap and heal the tree.

Wrap the joined area tightly with polyethylene grafting tape, (sometimes called tree tape) to keep the graft from drying out. You can also use grafting wax or grafting rubber bands. If you use the tape, you can actually watch for the callous as the the two surfaces join.

Grafted April 2008.

Keep your new tree out of hot sun, keep it well watered, and rub off any growth that appears below the graft union. Soon you should be able to see new growth emerging on your scion wood.

January 2009. A new , old tree!