I had two primary visions when we opened Decker's Nursery. I wanted it to be easier for homeowners and property managers to plant more trees and shrubs; and to provide a resource center for accurate information. It's been my experience that most tree failures are related to improper planting and/or improper care afterwards. Watering is the primary reason that trees fail, especially when they're new. Improper pruning and excessive mulch are the other (2) causes for plant failures after they've become established.
Knowing how and when to prune is important for maintaining plants, in landscapes and as street trees. This information is going to focus on Pruning.
Because Decker's Nursery is successful, and because our customers recognize the benefits and pleasure that comes from trees and shrubs, the Urban Forest in our communities is improving. Maybe not measurably yet; however Decker's Nursery assists in planting between 4&5,000 trees and shrubs every year.
As less undeveloped land is available on Long Island, the Urban Forest is what we're leaving our children & future generations. I firmly believe that planting more trees, shrubs and perennials will restore an imbalance that’s occurred as a result of “urban sprawl”. Our environment will benefit from each and every tree that's planted and grows to maturity.
When to Prune Woody Plants.
Maybe this should be more about when to NOT prune. New plantings should be allowed to simply grow for the first 2 years. It's not always practical however, it's more important for new plants to have as much foliage as possible. This is how plants create the energy required to be healthy. The more foliage you remove, the less vigorous the plant becomes.
On an annual basis pruning in spring is never preferred unless it's to remove dead tissue. Avoid pruning cuts when the sap is flowing or falling. As buds break and leaves are forming (flowing) or leaves are changing color and preparing to shed (falling).
Know the plant you want to prune. When does it flower, does it flower on old or new growth? If plants flower in spring (before June), its advised to prune soon after they finish flowering. This prevents cutting new flower buds off next year. Azaleas and Rhododendrons, Lilacs, many Spring flowering trees- Dogwoods, Redbuds, Cherries, etc. Prune in June after all the new growth has hardened off.
Plants that flower in late Spring or Summer/Fall usually flower on new growth and the window for pruning is more open ended. Prune any time after it stops flowering, through winter and up to St.Patricks Day. - PeeGee Hydrangeas, Smokebush, Butterfly Bush, Abelia.
Evergreens should be cut during the dormant season; late November through St.Patricks Day. Often homeowners don't like the appearance of evergreen hedges or shrubs that become "unkept". If the appearance of your evergreens is requiring pruning schedule it after after July 4th. This is when all the new foliage has hardened off and it prevents you from having to prune a 2nd time.
Remember these are principles, not written in stone. Nothing will die as a result of improper timing. You may have less flowers or sunburn leaves, or need to prune a subsequent flush of growth, but nothing catastrophic will happen.
Why Prune Shrubs?
Just a few take home messages:
1. Pruning is not a way to improve a declining plant. Common logic seems to be that if you prune a plant drastically and make it smaller, it will rejuvenate the plant. Please don't do this! it doesn't help a plant in poor health. There's an actual cause for an unhealthy plant and that's what needs to be identified. Removing 50% of the foliage will only stress a plant further.
There are times you can rejuvenate an overgrown plant by pruning hard; however it should be in good health to get the desired results.
2. Pruning is not something a plant desires. If they did, there would be little fairies in the woods doing the pruning. “Always have a purpose and objective for why you’re pruning.. weigh this objective against the downside of pruning which requires us to wound the plant. As you learn how to prune, you will minimize the damage that pruning causes.
Pruning is a necessity and doing it properly will provide benefits. Bad pruning is worse than no pruning.
The following objectives are the most common reason to prune
Sanitation - Pruning dead tissue is always beneficial and if this is all your doing; it's almost always a good time to perform crown cleaning.. Pruning infected (insects or diseased) tissue is beneficial.
Crown Reduction - is the most common reason that pruning is required. We ask plants to grow in confined areas that conflict with hardscapes and use of our propeties. This is also the most drastic pruning performed. If performed properly, Reduction pruning can benefit the plant and maintain a desired size and form. Thinning the longest or tallest branches back to a lateral branch or parent stem will accomplish a reduction in size.
It's likely to take time to learn this type of pruning, because it's slightly different for different types of plants.
Plant health - Structure and form are imporant for trees as they mature. Pruning trees to correct structural defects, crossing branches and co-dominant stems will prevent problems as trees mature.
This type of pruning is more technical than strenuous. It's an invaluable benefit to do this pruning when the tree is 8-12 years old and again when 5-7 years later. This pruning will assure a longer life span for the tree and reduce the need for significant repairs later.
Rejuvenation is not suitable for all plants however it may be practical with overgrown Euonymous, PG Hydrangeas, Butterfly Bush, Shrub Roses, and others - Rarely will an evergreen tolerate a drastic rejuvenation pruning. Rhododendrons are the ones that everyone wants to rejuvenate. I feel it's discrediting to any Ericaceous plant, (Rhododendrons, Azaleas, Mt. Laurel, Andromeda) and many survive. Only to lose the character and charm as they mature. Red Twig Dogwoods is a good plant to rejuvenate by removing older less desirable stems. Pruning the older stems maintains the bright red stems that are appealing in winter months.
Dead heading is a type of pruning and can be done as you like. Dead heading has minimal impact on the plant. Dead heading can be performed whenever you have time. There aren't any time restraints.
Pruning for aesthetics is rarely a good reason. Don't try to make your plants into Meatballs or Umbrellas, it does significant damage to them. If you have a rogue branch or stem that's way out of balance, prune it back or off the plant. Remember that trees & shrubs don't know they're supposed to grow symmetrically. In fact its highly unlikely to occur. See if you can find beauty with the imperfections and character of trees.
Shearing plants does make sense economically. There are times you have to shear plants to reduce their size. Just be aware that shearing does hundreds of improper cuts that damage & stress the plant. Determine if shearing is the only option before proceeding.
It's alright to shear, it just comes at a cost. I diagnose dozens of plants each year that are succumbing to over pruning caused by shearing. The drastic reduction of size ends up killing several branches in proximity causing large dead areas.
Shearing comes with a cost however it still makes the most sense with large evergreen hedges.
How to Prune - Be patient and observe how plants grow.
All plants don't grow the same. Watching them and observing them is how you make a connection with them. Look for the branching patterns, and form of the plants. Identify what makes each plant unique. It's while pruning that many people become connected with plants.
Always use clean, sharp pruners. Sharp pruners make proper, clean cuts. Select the proper tool for the job. Hand saw, hand pruners, loppers, shears, etc. Wear protective gloves when pruning plants with thorns.
Always cut at a lateral branch, this is critical, and pertinent when you're thinning a plant, or reducing a plant. If you don't have a lateral branch to cut back to; find a viable bud. This is common with hydrangeas and roses.
The angle and type of cut you make should always produce the smallest wound. Cutting on an angle is not preferred, because it makes a larger cut. Cut perpendicular to the stem or branch.
When thinning, don't remove more than 25-30% of the plants canopy. If you prune during the dormant season, you can be a little more aggressive.
Hydrangeas- Do not require pruning.
1. Every pruning discussion circles back to hydrangeas. They will be more healthy and produce more flowers if you don't prune them. If they become too large for their location you can reduce their size vertically and laterally.
Know the different types of hydrangeas and prune accordingly.
Big leaf hydrangeas - Prune as close to Sept. as possible. As the flowers are fading is a good time to prune.
If you want to reduce the spread of a Bigleaf hydrangea, find the branches, usually at the base of the plant, that extend outwards. Cut these branches all the way back to the base of the plant, and you'll notice how they become less wide.
If you want to reduce the height, find the tallest stems and cut them all the way at the bottom. This will thin the canopy (usually beneficial to reduce diseases) and leave the plant looking natural. If necessary reduce the height of remaining stems back to a viable budset. Always prune the dead tissue at the base inside the plant. This is a good sanitation practice.
Consider using dwarf varieties when planting Bigleaf hydrangeas (macrophylla).
PeeGee Hydrangeas & Smooth Hydrangeas - Prune after flowering and before St. Patricks Day. You can be aggressive with this pruning. (Hydrangea paniculata & serrata).
Prune the center of the plant to thin the canopy. Any branches that grow towards the center of the plant should be pruned at the next lateral branch. Once you complete the thinning, reduce the height and spread by cutting back to a bud set at the desired size. Reduce each branch the same amount to maintain balance.
Oakleaf hydrangeas are the same as PeeGee & Serrata with timing and how to prune.
Roses - Know your Rose
Shrub roses are very forgiving and become very large. If you prune them annually by thinning and reducing their size, they will perform better and are less likely to require rejuvenation pruning.
Tea Roses (Hybrid Tea) - When you cut the flowers to enjoy indoors, that's a form of pruning. Cut your flower stem at a lateral branch to prevent leaving a stub that dies back. Dead tissue facilitates fungal infections.
Pruning roses can be perceived as technical, cutting at certain buds, etc. Don't over think it and follow basic principles like lateral pruning and only reduce the rose as much as necessary. Allow the plant to get larger each year for overall health. Every formal rose garden I see appears harshly pruned to me.