top of page

Wyoming Apple Project

Propagation & Maintenance

  1. Rootstocks

  2. Grafting

  3. Planting

  4. Maintenance 

  5. Disease & Pest Management

New workshops (below) for grafting, pruning and restoring old apple trees!

  • Facebook - Black Circle

Rootstock

How to choose your rootstock

 

Choose your rootstock based off soil type, irrigation option, climate, production levels, cultivar and disease/pest resistance. Buying rootstock from more than a single nursery is recommended.  Including testing different rootstocks to see what grows best in your particular area of your land.. Keep in mind the production and area in which you have to grow with. Dwarf rootstocks will be more suited for back yards, while seedling or standard stocks reaching 20 feet tall are more suitable for larger production orchards. Dwarf rootstocks offer the added benefit of easy pruning and earlier production, but keep in mind standard are more tolerant in wetter and drier soils and anchor better.

There are five main types of rootstock; Budagovsky (Bud or B), Cornell/Geneva (G), Michigan Apple Rootstock Clones (MARK), Malling Merton (MM), Malling (M) and East Malling/Ashton (EMLA). EMLA are certified virus-free selections of M and MM. G rootstocks are often replant tolerant, which is handy for anyone purchasing a old orchard.

See Excel below for more information on (32) rootstocks pertaining to their size, fruiting, rooting anchorage, hardiness, soil adaptability, crown/root rot, fire blight resistance, replant disease resistance, wholly aphid resistance, suckering, burr knots and virus susceptibility

Grafting Workshop

Grafting

Grafting

A technique in horticulture that joins (i.e. inserted or affixed) and aligns vascular tissue of one plant to another.

Why grafting- Grafting is clonal reproduction allowing an easy way to propagate and persist a certain species. While possible from seed, the original cultivar is lost and will not produce fruit for possibly decades. Finally, grafting helps elevate self-compatibility issues, disease repair, damage, abiotic or biotic stress resistance and decrease infectious diseases. 

Terms 

Rootstock- The root system of the tree in which a scion or bud is grafted onto.

 

Scion- A piece of tree containing last years growth to be inserted into the       

Interstock- The section above the roots of the rootstock the scion or bud is actually grafted to.

 

Budding– Grafting that consists of inserting a single bud into the stock rather      

    

Types of grafts (PAGE UNDER REPAIR-NEW PHOTOS COMING SOON)

 

 

 

Whip graft

Whip and tongue graft

Cleft graft

Modified cleft graft

Side graft

Bridge graft

Budding

Others 

 

 

 

Tools

Budding and grafting knife

Fine tooth saw (cleft-graft)

Pruning shears

Hammer (bridge graft)

Tape material; grafting, adhesive, electrical and rubber strip tape

Asphalt water emulsion for sealing (cleft graft and side graft)

Thank you to the contributing participants of the grafting and pruning workshops, Dr. Brian A. Mealor and Chris Hilgert of the University of Wyoming, Department of Plant Sciences. A special thanks to Dr. Brian A. Mealor for hosting the Wyoming Apple Project at the Sheridan Research and Extension Center (ShREC) in Sheridan, WY, including providing the recording equipment and help recording the grafting workshop. A special thanks to Chris Hilgert for providing your expertise and allowing us to record the pruning workshop. 

Planting

Where to plant

When preparing to plant your apple tree choose a spot with full sun (8 hours a day), no standing water and a soil pH between 6-7.

           

Spacing

Provide horizontal spacing based off the anticipated height of your tree. Standard size trees will grow 20-25 feet tall, semi-dwarf 12-15 feet and dwarf 6-8 feet. Proper spacing will decrease shading from other trees and increase the quality of fruit coming from your tree.

 

Planting

Plant bare root tree as soon as the soil can be worked (April-May) and potted trees after threat of frost passes (May-June). Dig your hole as deep as the root ball and twice as wide.  Bair root and containerized trees should be examined for encircling roots or woody roots. Straighten the encircled roots or cut wood roots prior to planting as they may strangle the trunk or cause girdling of roots. Position the graft union about 4 inches above the soil to allow the cultivar to root and increase growth. This will also allow you to easily identify the true cultivar when sprouting occurs. Spread the roots in the hole.  Begin adding dirt, packing simultaneously to remove air pockets. Mixing in 1/3 part compost, peat moss or other organic matter is recommended. After filling the hole, tamp gently and water heavily to remove air pockets. Save left over dirt, as settling of soil may occur after tamping and watering. After planting you may want to consider installing a tree guard to protect from winter injury and small bark chewing mammals until tree develops thicker bark. After the tree creates secondary growth (i.e. flaky mature bark), remove the guard to prevent girdling.

 

Initial Pruning

Remove any limbs originating from the base of the tree and any branches below 24 inches. Choose only one leader branch if two or more are competing. Select three to four scaffold branches angling 60 degrees from trunk and cut out the rest of the branches. If you purchased a smaller tree with little branching or none, prune the trunk to 30 inches. This will help induce branching to create scaffold branches for your new tree. 

 

Support

You may want to stake out your tree for the first few years. Wooden or metal stakes work well with wide non-abrasive material to prevent damaging the tree.

 

Watering

Water your tree thoroughly during the growing season on dry spells. Trees should receive 1 inch of rainfall or irrigation every week from the months of May-October.

Maintenance 

Fertilizer and Mulch

Under favorable conditions, apple trees should survive without amendments. Nitrogen is primarily the only nutrient needed on an annual basis and can be applied using compost.  If using compost, apply around the base of the tree from April to May. Trees will commonly grow 12-18 inches/year, and young branches around 8-12 inches/year. If your tree exceeds this, stop applying amendments, as excessive growth inhibits fruit production and increases susceptibility to fire blight infection.

 

Harvest and Storage

Harvest fruit when it appears fully colored and not starchy tasting (August-October). Store apples in a perforated plastic bag or a loosely covered container. Apples can be stored between 33F to 38F, with roughly 85% humidity. A home refrigerator is the best place to store apples. 

Pruning

Trees should be pruned on a annual basis. Younger trees should be pruned less than older trees to avoid reduction of fruit and increased leaf growth. Ounce your tree has good growth on the first scaffolding branches, select another set of branches 12 inches apart from the previous set.  Prune trees to have spaced branches and a balanced appearance. Good pruning practice is temoving broken, dead, diseased and crossing limbs. Limbs getting bigger than the trunk itself and suckers coming from the roots should also be removed. Water sprouts will occur as vertical branches, these should be removed too. Saved your sprouts, as these an be useful for grafting material. Start cuts on large branches from the underside of the limb. Cuts should be made at the  branch collar to prevent encouraging (vegetative) growth below the cut. Prune trees before growth begins or the end of the coldest weather (March). 

Pruning & Training new and old trees

Thank you to the contributing participants of the grafting and pruning workshops, Dr. Brian A. Mealor and Chris Hilgert of the University of Wyoming, Department of Plant Sciences. A special thanks to Dr. Brian A. Mealor for hosting the Wyoming Apple Project at the Sheridan Research and Extension Center (ShREC) in Sheridan, WY, including providing the recording equipment and help recording the grafting workshop. A special thanks to Chris Hilgert for providing your expertise and allowing us to record the pruning workshop. 

Training

Bending of young branches is often needed to stop vertical growth and prevent damage to other branches. Branches are typically trained to be  in a 60-degree angle from the trunk.  If not, branches become to vertical with heavy fruiting can result in broken branches. To create a 60-degree angle, place a spreader between the branch and trunk.

Thinning fruit

Trees will produce an abundant crop in favorable conditions, so fruit should naturally fall off.  It is still a good idea to thin fruit manually, as trees will bear more fruit then it can support. Unmaintained heavy crops can force no crop production for the next year due to biennial bearing, including reduction a reduction of fruit size and quality. Try to leave 1-2 fruit per flower or 4-6 inches between fruit on a single branch. Remove the smallest fruit to encourage larger fruit growth (June-July) after fruit has dropped naturally.

Weeds

During the first 3-5 years remove grass and weeds occurring within a three-foot radius. Grasses remove soil moisture and nutrients that promote growth. A handy way to prevent weeds and grasses from growing around your tree is using mulch, but keep mulch a few inches from trunk. Rake up fallen leaves and fruit during August-October.

Winter Protection

Plastic tree guards or tree wrap prevent voles and winter injury from sun. Tree guards can be removed after 6-8 years, or when the bark becomes thick.  A good idea for all ages is to remove the guard during the growing season to prevent girdling. Apply winter protection wraps during November and look for vole damage through November-March.

Disease and Pest Management

Intro

All apple growers should develop an Integrated Pest Management (IPM). One that considers the site, irrigation, apple cultivar, rootstock, pruning, harvest times, and the local flora in your area. A good IPM also includes monitoring and removal regiments. A good IMP will help increase your harvest and  help reduce invasive pesticide used on your crops. If your apple tree becomes infected, consider life stage of tree, season and the oppropriate management action from the severity of the infection. 

A list of apple pests are provided to become familiar with them. If you need more help contact your local master gardner or nursery for more information. COMING SOON PHOTOS 

Apple scab

Apple scab is caused by Venturia inaequalis, a fungus that infects leaves and fruit. Its name comes from the “scabby” appearance of fruit.  Early scab infections on leaves and fruit will first appear olive green, later becoming brown to dark-brown. Fruit lesions will enlarge and harden, making your harvest unsuitable for eating as a dessert apple.

 

Good practices of scab infection prevention includes removal of fallen leaves, as leaves create a reservoir for the proliferation of the fungis. High humidity or rain has shown to correlate wtih increases in scab infection. Opening up the canopy (e.g. pruning) or planting in areas of earlier sunlight can help reduce infection.

Fire blight

Fire blight is a bacterial infection caused by a species known as Erwinia amylovora. Fire blight is common across the entire Rosacea family. It kills shoots, leaves, branches, blossomes and entire trees. Flowers infected will appear green grey turning to black. Shoots will turn green grey, later becoming weak enough to bend forming a shepherd’s crook. Leaves will appear green grey, later turning brown and wilting. Branches and twigs will appear darker, (e.g. reddish brown) bark will sink,  crack to create what is know as a canker.  Young shoots damaged should be pruned, but remember to use sterile techniques between infected trees.

 

Fire blight is more common in warmer wet weather. During these wet and warm seasons a cream or sticky droplet may ooze from the areas infected. Insects and other pests are attracted to the ooze, which allows transfer of fire blight to other parts of the plant and/or apple trees in the orchard. Regular pruning will help prevent winter damage that can lead to fire blight infection, as hail, heavy wind and snow damaging branches creates wounds on trees. 

Cedar-apple rust

Cedar-apple rust is another fungal disease that is caused by Gymnosporangium juniper-virginianae. This species spends half of its life infecting apple/crabs and the other half infecting species of juniper. The infection will damage leaves and fruit. Leaf spots will appear yellow, later turning bright orange-red with raised black dots. 

Black rot

Black rot is a fungal disease caused by Botryosphaeria obtuse. Characteristics of black rot include leaf spots, fruit rot and cankers on branches. Fruit will remain firm, however, rotten tissue will appear brown-black with concentric rings. Leaf spots develop circular lesion with purplish or reddish outer borders with tan interiors. Winter injury or damage is often contributed to infection, so removal of damaged and infected tissue is important. As with fire blight, crotches or branches closely growing together can damage another. So proper pruning, training and removal of dead material can prevent infection.

Apple maggot

The apple maggot or Rhagoletis pomonella is a common insect pest in cold areas like Minnesota. Fruit will become inedible for human use, but may be used for cider and animal feed. Fruit will often appear pitted and misshaped from eggs being layed in the fruit. This is caused from white larvae (maggots) feeding on the flesh. Characteristics of this also include  tunnels of brown rot. Management of apple maggots may include removal of fallen apples, bagging fruit with plastic sandwich bags, using trapping sticky pads and even sprays. 

Coding moth

Coding moth or Cydia pomonella is a internal feeder rendering your fruit inedible. It is very common in commercial orchards. Characteristics of doing moth are  tunnels towards the apple cores and a crumbly golden-brown excrement around the exiting hole of the flesh. Management includes removal of fallen apples throughout the growing season and using insecticide sprays. However it is not recommended to use these sprays prior to petals falling off as you may kill pollinating bees.

Other pests and infections

Sooty blotch and flyspeck 

Plum curculio 

Multicolored Asian lady beetle 

References

Andersen, P. C. 2000. Low-chill apple cultivars for north Florida and central Florida. UF-IFAS Extension, Univ. of Florida. HS764: 1-9.

 

Bailey, L. H. 1911. The nursery-book, a complete guide to the multiplication of plants. Macmillan Co. courses.cit.cornell.edu/hort494/mg/methods.alpha/WTMeth.html

 

Bussey, D. J. and K. Whealy. 2016. The Illustrated History of Apples in the United States and Canada. 1st ed., vol. 1-7, ser. 1, JAK KAW Press LLC.

 

Geneva. 2018. Apple rootstocks comparison chart V.3. Center for Technology Licensing at Cornell University. 1-3. 

 

GRIN, USDA. 2017. U.S. National Plant Germplasm System. GRIN-Global Web v 1.9.9.2. United States Department of Agriculture. Npgsweb.ars-grin.gov/gringlobal/search.aspx.

 

Hahn J. D., M. Grabowski, J. Mackenzie. 2011. Pest management for the home apple orchard. Retrieved from the University of Minnesota Digital Conservancy. http://hdl.handle.net/11299/198130

 

Hertz, L. B. 1979. Grafting and budding fruit trees. University of Minnesota. Agricultural Extension Service. Retrieved from the University of Minnesota Digital Conservancy. Bulletin No. 437. 1-16. http://hdl.handle.net/11299/169046

 

Hoover, E. E., S. Tepe., D. Foulk, and A. Klodd. 2018. Growing apples in the home garden. University of Minnesota Extension. https://extension.umn.edu/fruit/growing-apples-home-garden

 

Jensen, S. L. 2018. Tree fruit diseases: 2018 fungicides for home garden use in New York state. Cornell Cooperative Extension, Cornell Univ. http://ccesuffolk.org/gardening/horticulture-factsheets/tree-fruit-diseases

 

Klass, K. 2003. (Revised 2012). Reprint from Apple maggot Rhagoletis pomenlla (Walsh); Family: tephritidae (fruit flies). Cornell Cooperative Extension, Cornell Univ. 1-2.

 

Magby, J.T., and S.L. Miller. 2018. Wyoming Apple Project: Steve Miller Lab. Univ. of Wyoming., Laramie. www.wyomingappleproject.com/.

 

Miller. S. L. 2018. Grafting presentation. University of Wyoming Department of Botany. 

 

Nelson, A. 1905.  First Biennial Report. Wyoming State Board of Horticulture, Univ. of Wyoming., Vol. 2.

 

Nelson, A. 1907. Second Biennial Report. The Wyoming State Board of Horticulture, Univ.  of Wyoming., Vol. 2.

 

Nelson, A. 1909.  Third Biennial Report. Wyoming State Board of Horticulture, Univ. of Wyoming., Vol. 3.

 

Nelson, A. 1912. General Notes: The State Experimental Fruit-Farm-The Horticultural Society. Publications of the Wyoming State Board of Horticulture. Univ. of Wyoming., Vol. 1., No.3.

 

Nelson, A. 1915. Sixth Biennial Report. Wyoming State Board of Horticulture, Univ. of Wyoming., Vol. 6., No.104.

 

Nelson, A. 1916. Horticulture and the Home. Publications of the Wyoming State Board of Horticulture, Univ. of Wyoming., Vol. 1., No.5.

 

Nelson, A. 1918 (Jan). War-Time Horticulture Index. Publications of the Wyoming State Board of Horticulture. Univ. of Wyoming., Vol. 1., No.6.

 

Nelson, A. 1918 (Dec) Seventh Biennial Report. Vol. 7th, Publications of the Wyoming State Board of Horticulture, Univ. of Wyoming., Vol. 7.

 

Nelson, A. 1924-1925.  Wyoming Experimental Station: The State Experimental Fruit Farm. Wyoming State Board of Horticulture , 2nd ed., Vol. 3. repository.uwyo.edu/ag_exp_sta_bulletins/.

 

 

Sideman, B. 2010. Growing fruits: care of mature backyard apple trees. UNH Cooperative Extension, Univ. of New Hampshire. 1-5.

 

University of Wyoming Agricultural Experiment Station. 1897.  Fruit Growing in Wyoming. Univ. of Wyoming., Bul. 34:86-157. http://repository.uwyo.edu/ag_exp_sta_bulletins/35/

 

USDA, ARS. 2016. Characteristics of apple rootstock. Plant Genetic Resources Research. Geneva, NY, ARS (translated).

 

USDA, and R. MacDonald (Edited). 2017. USDA pomological watercolors NAL digital collections. U.S. Department of Agriculture. Usdawatercolors.nal.usda.gov/pom/home.html.

 

Washington State University., and J. Wendy. (Edited). 2016. Apple rootstocks. WSU Tree fruit Extension, Washington State Univ.  treefruit.wsu.edu/web-article/apple-rootstocks-2/

 

WSU Tree Fruit. 2018. Orchard management: crop load management. WSU Tree fruit Extension, Washington State Univ. http://treefruit.wsu.edu/orchard-management/crop-load-management/

 

WSU Tree Fruit. 2018. Orchard management: harvest. WSU Tree fruit Extension, Washington State Univ. http://treefruit.wsu.edu/orchard-management/harvest/

 

WSU Tree Fruit. 2018. Orchard management: pruning and training systems. WSU Tree fruit Extension, Washington State Univ. http://treefruit.wsu.edu/orchard-management/pruning-and-training-systems/

bottom of page