Youth Gardening and Pruning Apple Trees

Welcome to Northern Gardening.

In this month's program, Karina Roth discusses the food program at Great Expectations School and how the school is using the greenhouse to grow food for lunches at the school.
She also has some requests for help from the community. Karina can be reached at 387-1876 if you can help.

• The Food  Committee’s goal is to continue to have more locally produced food  for their lunch program at Great Expectations School. They have a greenhouse, but need help with adding more ventilation to it to use during warmer weather. This would allow more use of the greenhouse for growing warm season crops without over-baking.
• Karina is also looking for people to help start tomatoes and peppers for the Great Expectations Plant Sale. Is anyone willing to help start them or take care of plants at your home? Call her at 387-1876.
• GES could also use addditional indoor plant light stands, either be purchased or built, for more plant-starting options. Call Roth if interested.

Max Linehan, U of M master gardener, was in the studio to discuss the children’s gardening programs she does in conjunction with another U of master gardener, Penny Ortman. They are always looking for willing hands and help with their programs. These are the two upcoming sessions being offered.

• Spring Session will be on Tuesdays, April 17 – May 22 from 4 – 5 p.m. at the 4H Log Cabin Building at the Cook County Community Center.  Youth in grades 3 – 8 grade are welcome to sign up for the After School Lounge program and walk over with them right after school. The program is free if your student participates in the After School Lounge program. If your child wishes to attend just the gardening program, the cost is $10 and parents need to be responsible for dropping child off and picking them up.
• Summer Session will be on Tuesdays, June 12 – August 22. If your child is part of Summer KIDS Camp, then they will be automatically participating in this program. If you would like your child to just attend the Summer Gardening program the cost will be $15 for the summer to help pay for materials, etc.

If there is interest in having youth gardening programs either at Birch Grove Center in Tofte or up in Grand Portage, please contact Diane Booth in the Extension office at 387-3015.

Apple Tree Pruning Basics

Older trees that were planted years ago were on standard root stock so they grew quite large and were difficult to prune as they became older. Most apple trees being planted now are on semi-dwarf root stock or dwarf rootstock. These are less hardy than standard root stock, but reduce the size of the tree so that you can plant them closer together. To grow well you need to mulch, make sure they have good snow cover, and remove grass competition.

Regardless of the rootstock you choose, the training of the small tree will help determine the type of pruning you have to do on the mature tree later.

Correct training and pruning are important because they will affect time of production to some extent, sustained high yields, optimum fruit quality. You need strong branches that can hold a lot of fruit without breaking. And there has to be a balance between vegetative growth and growth that will produce fruit.

Pruning removes unproductive growth and encourages growth of new bearing wood so that at the end of each growing season, the top of the trees and the roots are in balance.

Dormant pruning removes some growing points, and this increases the root resources for the remaining buds.

Light exposure is very important for fruit production. The top of the tree will receive the most light. The middle of the tree will receive about 60 percent light and still be productive. If the lower, center part of the tree only receives 30% light, it will become less productive with smaller fruit and not good color.

• Light exposure also depends upon the size of the tree. 
• Open center trees that have a dense canopy at the top will shade more of the tree resulting in less production.
• Pyramid-shaped trees exposes more leaf area to sunlight resulting in more productivity.
•  Increased fruit production reduces the amount of tree vigor going elsewhere and helps control the tree, shoot growth and tree size.
• Branches that are almost horizontal will reduce vegetative growth and more flower formation is stimulated. Branches that are bent below the horizontal will have more vigorous upright waterspouts near the base of the branch.

All pruning cuts can be classified as:

• Heading back – removes only a portion of a branch resulting in usually vigorous growth. Cut directly above a bud. These cuts should best be done on 1-year growth rather than on older wood. Used on older wood induces waterspout growth. 
• Thinning out – an entire branch is removed at the junction of the trunk or lateral branch. Doesn’t result in vigorous growth. Make sure you leave the branch collar.

So, if you are planning to purchase a new apple tree this year or if you have planted one a couple of years ago, here are some suggestions for working with your young apple trees. There should be an emphasis on training a young tree rather than pruning  it – you should very limited pruning on young trees.

The First Year

• Pruning should be limited to cuts necessary for proper tree development and broken branches.
• If you have a single whip (1 leader only) then you will need to head it back at about 30” – 36” to induce laterals to develop. All shoots developing below 18” should be removed.
• Try to avoid heading back laterals.
• Train a central leader for dominance to keep laterals in check. If the leader grows by more than 18” you may need to cut it back by ? because you want a strong leader.
• Fruit forming on central leader needs to be removed to keep that dominance.
• Use spreaders or weights to make sure the laterals have wide crotches for strength and better fruit bearing. Spreading the laterals will increase flower production and reduce vegetative growth. 60 degrees.

The Second Year

• If you didn’t have laterals to spread the first year, make sure your laterals that grew last year that you are keeping are spread to 60 degrees. (easier after bud break)
• Keep your central leader dominant. Remove any competing laterals.
• Each lateral should be 8” from another lateral branch. They should not be clustered in the same area along the trunk of a tree.
• Lower laterals on the tree should be longer to keep conical shape and allow more light. As the laterals develop, they may start growing vertically again and you will need to keep moving the crotch angle to 60 degrees.

Three to Five Years

• Continue to make sure you keep your central leader dominant.
• Keep your laterals in that conical shape.
• Continue selecting specific laterals to keep and removing others at the main trunk.
• You may end up doing more thinning cuts to remove unnecessary branches.
• The key is to keep good light exposure and keep the tree from becoming vegetatively vigorous. You want the energy of the tree to go into fruit production.

Trees that are Bearing Fruit
Dormant pruning should be done in late winter before bud break. This time of the year reduces susceptibility of tree injury due to low temperatures.

• Pruning trees after bud break or when in bloom can increase spread of diseases.
• Branches growing upright into the interior of the tree can be thinned back to the lateral.
• Branches growing down below a major lateral that are shaded can also be thinned back to the lateral.
• Keep branches that are growing horizontally from the lateral.
• purs are short 3- 5” branches that produce flowers and fruit on apple trees. Sometimes they become long, weak and heavily branched. You can thin them out and head them back to a strong bud.
• Some spurs that are underneath a lateral branch can be removed to encourage more spur production where there is more light.
• Remove water spouts and upright shoots.
• Remove branches that are crossing and/or  dead or injured branches.
• Once the height of the tree has been reached (8 – 10 ft dwarf) (12-16 ft semi-dwarf) you can cut the leader to a weak side branch. You will probably need to do this every year to keep it at that height. Laterals will all need to remain shorter than leader you will need to prune back into 2-year-old wood.
   

If you have older apple trees that have not been pruned for a number of years, here are some additional suggestions you may want to follow:

What do I do if I inherit older apple trees that have not been pruned?

• First decide if you want to keep the tree or do you want to replace it with a new apple tree you can start training and pruning correctly? Do you like the fruit?
• Does the tree receive all day sun?
• Plan a 3 – 5 year recovery for this older tree.
• Cut out all the dead wood.
• If you find any diseased wood, cut that out next, making sure you disinfect your tools by wiping the blades with Lysol or ethanol or isopropyl alcohol. These are all better than bleach solutions. Burn all diseased or insect-infested wood.
• You cannot remove more than 1/3 of the wood from the tree at a time and really should probably remove less.
• Start by opening up the tree and removing branches that grow straight up.
• Prune more heavily in the upper part of the tree first to get more light into the tree.
• Cut out narrow crotched branches.
• Cut out branches that are crossing each other.
• Remove droopy branches – less fruit production or small fruit production.
• Prune with a bud facing outward to force the new branch to grow in that direction.
• If you have multiple leaders and no central leader, you may have to prune the best you can while keeping the open or vase shaped configuration.

If you have questions, call Diane Booth at 387-3015. Here is a link on pruning apple trees with diagrams included.

In other gardening news, the Cook County Extension office has copies of the 2012 guide to good vegetable varieties to grow in the county. They are free and can be picked up at the Cook County Community Center. Copies are also available at local stores.

The Northwood Food Project is accepting applications to serve on its board. Call 387-3015 for more information.

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