460 likes | 1.05k Views
Pruning Trees and Shrubs. Rick Abrahamson University of Minnesota Extension Clay County. When should trees and shrubs be pruned?. January - February. Oak Oak Wilt Elm Dutch Elm Disease. March. Oak Ash Ash borer Birch Bronze Birch borer. Fireblight control Apple/crabapple
E N D
Pruning Trees and Shrubs Rick Abrahamson University of Minnesota Extension Clay County
January - February • Oak • Oak Wilt • Elm • Dutch Elm Disease
March • Oak • Ash • Ash borer • Birch • Bronze Birch borer
Fireblight control Apple/crabapple Mountain-ash Cotoneaster Shade and ornamental trees Hackberry Linden Poplar Early April (1st – 15th) • Stem canker control • Honey-locust
Early April (1st – 15th) • Viburnum • Evergreens • Spruce • Shrub flowering habits • Hydrangea • Bush Honeysuckle • Spireas (summer) • Foliage shrubs • Alpine currant • Barberry • Dogwood
Flowering habits Apricot Chokecherry Flowering Cherry Juneberry (Serviceberry) Forsythia Evergreen Arborvitae Juniper Yew Late April (15th – 30th)
Flowering habits Flowering Plum Japanese Tree Lilac Chokeberry Lilac Mockorange Potentilla Spirea (early) Shrub Rose May - June
May - June • Bleeding • Maple • Boxelder • Black Walnut • Ironwood • Weeping Willow • Kentucky Coffee Tree • Evergreens • Pine
July - August • Evergreens (don’t prune after August 15th) • Arborvitae • Yews • Juniper
September - December • Leave pruning tools in storage • Healing of wounds slower in fall • Drying and dieback more likely • Decay fungi spread high • Exception • Oak and Elm
That’s good information, but… How should trees and shrubs be pruned?
Prune for function • Broken, diseased, and dead • Obstructing limbs and branches • Clear doors and windows • Form, shape, vigor, and beauty
Why prune? • Control habit of growth • Remove dead, broken, and diseased • Produce desired shape and form • Improve flowering and fruiting • Improve survival rate
Pruning equipment • Hand Shears • Pruning Loppers • Pruning Saw • Pole Tree Saw
Pruning equipment • No buckets, ladders, or boxes!!!!! • Stay on the ground!!!!! • Get professional help, know what you want and make sure it is done right.
Botany of pruning • Branches elongate from buds • Branches increase in diameter from the cambium
Where to cut? Grow your plants by choice, not by chance.
General pruning • Keep diseased, broken, and dead branches pruned out at all times • Avoid weak crotches • Remove cross over and interfering branches • Prune to side branches or main trunks • Never leave stubs, snags, or ragged cuts
Heavy and large cuts • Under cut • Over-cut off • Stub removal at shoulder ring
Future of your tree Weak crotch left on Pruned up to high to soon Open spreading form Prune to a central leader Future lies in your hand and your head!!!
Directional pruning for trees • Top work • Reduce size • Clear overhead lines • Prune to side branches • Stub causes “Bird nesting” • Prune limbs to shoulder ring • Proper cut = small wound, fast healing • Flush cut = large wound, slow healing
Deciduous shrubs • Rejuvenation • Induces new and compact growth • Do not top!!!!!! • Heading Back • Reduces size • Cuts made to side branches or buds!
When shrubs get old and leggy • Consider rejuvenation • Remove half of existing old canes • Next year remove remaining canes • Keep new growth pinched back to induce side branching and compact growth • Cut all growth back • All growth new • Removal and replanting • May be most practical and economical
Prune Junipers with a purpose • Start when plants are young • Strive for a disciplined form • Avoid neglect and abuse Discipline: “Training which corrects, molds, strengthens, or perfects”
Prune Junipers with a purpose • Avoid sheared and ugly ends • Stops terminal growth and avoids stringy growth • Cut deep • Back in to a top growing branch • Pinch back new, young shoot growth as it develops each season
Building an upright Juniper • Single center trunk (Leader) • Prune selectively • Do not shear • Vertically growing branches • Bend for more horizontal position • Head back or prune down as far as possible
Building an upright Juniper • Close branching causes crowding • Remove weakest or poorest of those in conflict • Rejuvenation • Prune down to desired size and form • Replacement may be better choice • Proceed with courage! • Always leave some green
Low hedge (1-3’) Pygmy Caragana Alpine Current Dwarf Gooseberry Medium hedge (3-6’) Globe Caragana Alpine Current Dwarf Ninebark Large hedge (>6’) Honeysuckle Rocky Mountain Juniper Black Hills Spruce Common Lilac Chinese Lilac Colorado Spruce Building a hedge
Building a hedge • Screening hedge (>10’) • Eastern Red Cedar • Flowering Crabapple • Siberian Crabapple • Common Lilac • Amur Maple • Siberian Peashrub • Black Hills Spruce • Colorado Spruce
Time for a test Good luck!