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Crocus are blooming

Male spring peeper calling; photo credit Jack Ray

Male spring peeper calling;
photo credit: Jack Ray

The other night as I drove past a small pond on my way home, the chirping of the spring peepers was deafening! But I was happy to hear them!

Spring is near!

The peepers are singing, the crocus are blooming, and the daffodils are beginning to open! It seems that spring is slowly creeping into the Shenandoah Valley.

It has definitely been an odd winter this year with some very warm stretches mixed in with a few very cold periods. Some perennials have been fooled and many broke into growth earlier than they should have.

In late January, we received the following question via our Discussion Board:

Hosta damaged from a late freeze can be cut back

Even hosta damaged from a
late freeze can be cut back

I am in Toano, Virginia. We had an unusually warm start to our winter. As a result, my blueberries bloomed, my peonies started to come up as did my daylilies. Some of my daylilies never really went dormant. I covered the daylilies and peonies with pine straw but the daylilies grew almost 6 inches. Now the leaves are burned and chewed. Can I cut the leaves back to the ground now or [should I] leave them alone?

This type of plant damage is not unusual but it normally occurs in the spring when a late freeze damages the tender new spring growth. It’s a bit crazy that there was this much growth during a warm spell in the winter but, as we all know, it was a crazy winter!

Freeze damage on daylilies resembles insect damage.

Freeze damage on daylilies
resembles insect damage.

Here is my response to the question:

Yes it would be fine to cut the damaged foliage of your daylilies back. You can cut them right to the ground. The “chewed” leaves are probably a result of freeze damage rather than damage from a chewing pest. Re-cover the plants with the pine straw after you trim them back.

Pine straw makes a great, long-lasting mulch and the daylilies and peonies will grow right up through it.

Cut Liriope back before growth begins in spring

Cut Liriope back before
growth begins in spring

March is also a good time to trim back the old foliage of some of your evergreen perennials – especially Liriope, Helleborus, and Epimedium. It is so much easier if you do this before the new foliage begins to grow. You can pretty much just gather up the old leaves in a bunch and cut the stems close to the ground. Just be careful that there is no new growth in the way of your shears before you snip!

The old fronds of evergreen ferns should also be cut back now. Last weekend, I trimmed the old foliage from my Dryopteris, cinnamon ferns, ostrich ferns, and Christmas ferns.

Trim back old fern fronds before new growth occurs

Trim back old fern fronds
before new growth occurs

The crowns of these ferns were still firm and tight but the fiddleheads will soon begin to pop up and unfurl. After that, it will become harder to clean up the old foliage without snapping off the tender new fronds.

Ornamental grasses should also be cut back now. This is another group of perennials that is important to cut back before new growth begins. One of the easiest ways to do this is to cinch the old foliage together with twine or a bungee cord and use hedge shears to cut the clump back near the ground. Since it’s already tied up, you can just carry the whole bundle out of the garden. Nice and neat!
Here is a video showing just how easy this method is.

Oh and don’t forget!

Mark pruned this overgrown lilac back to the ground.

Mark pruned this overgrown
lilac back to the ground.

If you have some shrubs that have outgrown their space, now is the time to do any heavy rejuvenation pruning. This can be done with boxwood, holly, yew, rhododendron, azalea, and any others that have dormant buds in the bare wood. Even spring bloomers like overgrown lilac and forsythia can be pruned back hard to rejuvenate them and improve blooming, in addition to getting them back to a manageable size.

Normally, spring blooming shrubs are pruned after they finish blooming but severe pruning, where they are cut back hard (sometimes to the ground) is best done while they are still dormant in late winter or early spring. Of course you will sacrifice the bloom for the season but they should bounce back and bloom even better next spring or maybe the spring after.

Winter is on the way out! It’s time to get back in the garden!

Until next time – Happy Spring!

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A bright red cardinal sits atop a snowy honeysuckle
With the impending nor’easter heading toward the mid-Atlantic and southern New England, homeowners have been stocking up on supplies in preparation. Many may also be thinking about ways to prevent damage to their trees and shrubs that may be caused by a heavy snow burden.

A rhododendron droops under the weight of the snow.

A rhododendron droops under
the weight of the snow.

Here are some tips:

With snow accumulation, if it’s not too wet and heavy, you can sometimes take a broom or a leaf rake and gently brush the snow from the branches. If you keep up with this throughout the storm, you can prevent a heavy buildup. It is best not to shake the branches as this can cause breakage.

In the case of an accumulation of ice or heavy, wet snow, it is better to just wait and let it melt off naturally. If you try to knock it off you will usually do more damage to your trees and shrubs. It’s also very dangerous! Most trees and shrubs will bounce back after the snow or ice melts off so it is usually safer to be patient and wait until they thaw out.

Boxwood nearly flattened by a heavy load of snow

Boxwood nearly flattened by
a heavy load of snow

Snow damage is usually worse on evergreens because the foliage can hold the snow on the branches. Sometimes, the outer branches of shrubs like boxwood, yew, and azalea become weighed down with snow, separated from the center, and pinned to the ground. If you try to remove the snow, you can do more damage to the shrub. Let the snow melt off naturally! Once everything melts, you will be able to see if any permanent damage was done.

Click for some tips for dealing with snow damaged shrubs

What should you do for damaged trees in the aftermath of a destructive winter storm?

Heavy, wet snow can sometimes cause irreparable damage to trees

Heavy, wet snow can sometimes cause irreparable damage to trees

The most important thing is to be safe!

  • Don’t go near trees or branches that have fallen on power lines.
  • Watch for large broken branches that are hanging precariously and could fall in a gust of wind.
  • Assess the damage to determine if it is something that you can handle yourself or if you need to call in a professional tree service for help. Large limbs can be extremely heavy (hundreds of pounds) and dangerous!
  • Avoid any trimming or pruning that necessitates getting up on a ladder. This can be extremely dangerous especially if there is snow or ice on the ground.
  • When using a pole saw or trimmer, be mindful of any telephone or power lines and stay well away from these. It’s very easy to lose track of where they are in relation to where you are cutting! Better yet, leave this pruning to a professional.

What is the first step?

Large branch on a maple broken during an early fall snowstorm

A large maple branch broken
during an early fall snowstorm

The first thing you need to do is evaluate the damage to your tree. Study it from all angles and determine the best way to proceed. Severe damage may warrant a call to a professional tree service like Bartlett Tree Experts, while more minor damage can often be tackled by the homeowner.

Broken branches are one of the most common types of storm damage to trees, whether by snow, wind, or heavy rain. The three D’s of pruning dictates that you can remove these broken branches at any time regardless of when they occur. This is mainly because the ragged wound left from the break can be an entrance point for insects and disease.

Remember, hire a professional to remove very large branches or those that you can’t safely reach from the ground. Ladders can be very dangerous for pruning!

Tips for removing broken branches safely and with minimal, additional damage to the tree

  • Make clean cuts by using a sharp tool – a clean cut speeds callus formation and healing.
  • When removing a branch, make the cut close to the stem just outside the natural branch collar. The branch collar or bark ridge is an area/ridge at the base of a branch that contains cells that multiply quickly to close off and heal a wound. If you cut the branch inside this branch collar, you hinder the natural healing properties of the tree.
The natural branch collar contains cells that speed healing.

The natural branch collar contains
cells that speed healing.

Proper pruning removes the branch just outside the branch collar.

Proper pruning removes the branch
just outside the branch collar.

 

  • Leaving stubs is a very poor pruning practice.

    Leaving stubs is a very
    poor pruning practice.

    Do not leave stubs. Leaving a stub is almost worse than cutting the branch too short. Stubs will die back and leave the tree open to disease and insect damage. The tree cannot heal over a stub.

  • Smaller branches, less than 2″ in diameter, can be removed with one cut using good quality shears or loppers.
  • Remove larger branches in sections. This takes the weight off the break and makes the final pruning cuts easier and safer.
  • Once you have a shorter section to remove, use the three-cut method to remove the branch completely. The three-cut method prevents tearing or stripping of the bark as the final section is removed.
The first two cuts of the three-cut pruning method. The third cut will remove the remaining stub.

The first two cuts of the three-cut pruning method.
The third cut will remove the remaining stub.

  • There is generally no need to use any kind of wound paint. Painting the wound can inhibit the natural healing of the tree; however, sometimes larger cuts can be coated with orange shellac.
  • If a branch has broken and peeled the bark down on the trunk in the process, remove the branch using the procedure above and then trim off any loose bark.

Here are some tips for dealing with split branches or trunks

Severe damage to trees

Always prune to an outward facing branch or bud.

Always prune to an outward
facing branch or bud.

In many cases, depending on the species of tree, younger trees can bounce back from fairly severe damage – up to 40% loss of their branches. These smaller trees should be pruned to remove damaged branches, making new clean cuts back to a branch collar. If just the tip of a branch is damaged, prune the branch back to an outward facing branch or bud.

In the late spring, you will be able to determine if the tree has survived. Summer pruning may be necessary to reshape the tree and remove additional dead twigs or branches.

In cases of severe damage to larger trees, it is best to consult a certified local arborist such as Bartlett Tree Experts to get their recommendation on whether the tree can be salvaged. If the loss of branches is greater than 40%, the chances of survival can be greatly diminished and you may have to have the tree removed. Even if it survives, it may be severely weakened and it may become a hazard in the future. It’s wise to consult a professional arborist to determine a course of action.

Trees are a renewable and replaceable resource.

If you are forced to remove a tree, consider replacing it with a tree that produces well-spaced, wide angled branches which provide greater strength and resist breakage. To eliminate the problem of trunk splitting, look for trees that produce a single main trunk. Bradford pears are very popular landscape trees but they have weak branches and are very prone to storm damage.
Consider the loss of your tree an opportunity to try an exciting new variety!

Until next time – Be safe and enjoy the snow!

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The rhododendron bald at Craggy Gardens

A few weeks ago, Eric and I took a trip down the Blue Ridge Parkway. We tried to time our trip to coincide with the rhododendron bloom in the North Carolina mountains, specifically at Craggy Gardens on the parkway just north of Asheville. While the native rhododendrons, Rhododendron catawbiense, were just beginning to show some color, the flame azaleas and mountain laurel were in full bloom. It was beautiful!

Mountain laurel in full bloom.

Mountain laurel in full bloom.

Azalea gall on native flame azalea

Azalea gall on native flame azalea

When we stopped to take some pictures, we noticed that a few of the azaleas had some strange growths on them that looked like some type of gall. It turns out that this was the azalea gall which is quite common on both native and hybrid azaleas. Catawba rhododendron is also quite susceptible. In fact, the majority of the rhododendrons growing on the rhododendron bald above the Craggy Gardens Visitor Center had at least a few of these unusual, fleshy galls.

I’ve written about galls on plants before but most of those I have talked about were galls that developed in response to insect activity.

Azalea gall has caused swelling and distortion of young leaf tissue of this native rhododendron

Azalea gall has caused swelling
and distortion of young leaf tissue
of this native rhododendron

The azalea gall, Exobasidium vaccinii, is caused by a fungus which infects the leaves, flowers, and branch tips of azaleas, rhododendron, and certain species of Vaccinium like blueberries and cranberries.

The fungus causes abnormal growth in the tissues that are infected. These swollen tissues form the gall and cause distortion of the leaves, stems, or flowers.

Azalea galls can be light green, pinkish, or (as we most often observed) white.

This pale green gall will become white once the spore layer forms

This pale green gall will become
white once the spore layer forms

During the late spring and early summer, a white spore layer forms on the surface of the gall. This may be why all the ones we saw were white. These spores are dispersed by wind or rain to healthy leaves or flower buds on the same or different susceptible plants. The fungus remains dormant in these tissues until the following spring when new galls form soon after the plant begins to grow. Once the spores are released, the gall begins to turn brown and eventually dries up and falls to the ground.

Cool, wet weather favors the dispersal of the fungal spores. Up on the ridge tops of the Blue Ridge Mountains where native rhododendron and azalea are prevalent, fog and misty rains are common in the spring and summer. These conditions are perfect for the spread of this disease.

The rhododendron bald at Craggy Gardens is enveloped in a misty fog

The rhododendron bald at Craggy Gardens is enveloped in a misty fog

A rhododendron flower is completely distorted by a gall

A rhododendron flower is
completely distorted by a gall

Though the azalea galls may look harmful, normally, they do not have an adverse effect on the plants. However, if cool, wet weather persists during the time of spore dispersal, the disease can spread more readily and result in the formation of many more galls the following spring. This can sometimes have a negative effect on the health and vigor of the plant.

Usually only a portion of the flower head is affected.

Often only part of the flower head
is affected by the gall.

Azalea gall is a common problem in many hybrid azaleas. Physical removal of galls is the simplest control method. Galls should be pruned out with shears before the white spore layer forms.

If galls are prevalent or conditions are favorable for the spread of the disease, fungicide applications may be warranted. Bonide Fung-onil or Bonide Mancozeb can be applied according to the label directions to control azalea leaf and flower gall. Begin applications just prior to bud break in the spring.

Until next time – Happy Gardening!

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Euonymus alatus - burning bush

Euonymus is a large genus of plants which includes many species of deciduous and evergreen shrubs, trees, and vines.

Euonymus 'Silver King' is a beautiful variegated evergreen form.

Euonymus ‘Silver King’ is a beautiful variegated evergreen form.

Probably one of the most well-known of these is Euonymus alatus (Winged Euonymus, a.k.a. Burning Bush). This deciduous species is especially popular for its beautiful red fall color. Other popular species are the evergreen forms, Euonymus japonicus, Euonymus kiautschovicus, and the trailing Euonymus fortunei. Many of these evergreen cultivars have attractive variegated foliage.

Because of its diversity, euonymus has many different uses in the landscape. Some varieties are planted as stunning specimen plants, while others are used as an attractive living screen or hedge, and still other varieties create a lovely evergreen ground cover or trailing rock wall cover.

Burning bush in all its glory!

Burning bush in all its glory!

Few shrubs in the landscape provide brilliant fall color as reliably as the “Burning Bush” (E. alatus). When the temperatures begin to drop in the fall, this beautiful shrub transforms from a deep green to a striking fiery red. It’s no wonder these shrubs are so popular in the landscape – many even consider them overused! It should be planted in full sun to achieve the most intense fall color.

Unfortunately, Euonymus alatus and another popular deciduous species, E. europaeus, have escaped into the wild and have become invasive in some areas of the country.

Fruit capsules of E. europaeus will split open to reveal bright red seeds

Fruit capsules of E. europaeus will split open to reveal bright red seeds

The colorful fruit capsules which appear in the fall and add to their beauty in the landscape split open exposing equally colorful seeds. These seeds eventually drop to the ground and can produce hundreds of seedlings under the shrub or are eaten by birds and dispersed to other areas where they can germinate and grow.

The evergreen species, Euonymus japonicus, includes many of the more colorful variegated cultivars. Variegated cultivars should be planted in full sun to light shade for the best color.

Spreading euonymus (E. kiautschovicus) is a beautiful evergreen or semi-evergreen species with glossy dark green leathery leaves that is often grown as a hedge or living screen. ‘Manhattan’ is one of the most popular cultivars. Unfortunately, this species is prone to winter burn in colder zones.

Winter creeper, E. fortunei, is an evergreen species with a trailing habit which, depending on the cultivar, can be used as a ground cover, low shrub, rock wall cover, or as a climbing vine. There are many beautiful variegated cultivars in this species as well.

Finally – Pruning!

I originally began writing about euonymus because a few days ago I received a post on our discussion board about pruning these plants. I got a little off topic! Here is the question:

I have several overgrown Euonymus shrubs that have come into my hydrangea shrubs. I would like to cut the [euonymus] back but how far can I cut them and when is the best time?

How Much?

As far as how much they can be cut; these plants can really be pruned back as hard as you want or need to. Like many shrubs, euonymus has dormant buds in the bare wood and new growth will sprout below the pruning cuts so eventually you will end up with a beautiful, fresh, new but more compact shrub.

When?

The timing for pruning euonymus depends on the type, deciduous or evergreen – hence my discourse on the various species!

Euonymus alatus pruned to tree form.

Euonymus alatus pruned to tree form.

Deciduous euonymus should be pruned in late winter or early spring before they start to leaf out. As I mentioned, these shrubs can be pruned hard if needed, even back to 3″ – 6″ from the ground. They can also be pruned less drastically, removing dead and crossing branches, thinning out about a third of the oldest stems (all the way to the ground), and pruning the remaining stems to create an attractive, natural looking shrub.

These euonymus can also be trained to grow as a small tree by pruning out all but 1-6 main stems and removing any lower branches that develop along these main stems.

The pruning time for evergreen euonymus depends on how hard you need to prune them. If they need to be cut fairly hard to rejuvenate them or to bring them down in size if they have grown too large for your space, this should be done in late winter or early spring while they are still dormant.

If you just need to prune them back to shape them or reduce their size a little, you can prune them in the late spring or early summer when they are growing. It is best to avoid pruning them after the end of July or any new growth will not have time to harden off before winter.

Remember

If you need to do any “severe” pruning of your other shrubs like holly, boxwood, rhododendron, or yew, now (while they are still dormant) is the time to do it.

Be sure to fertilize them with Espoma Holly-tone, Plant-tone, or Tree-tone after you prune!

Until next time – Happy Spring!

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Acer griseum has attractive foliage and interesting bark

Recently, we’ve been talking about transplanting some of our trees and shrubs. I’m not talking about digging them and replanting them in OUR yard but digging them, potting them up, and eventually planting them next summer at my mom’s in Vermont and at my son’s new home in Maine.

This Hosta 'Green Pie Crust' has beautiful fall color. We will definitely divide and share some of these!

Hosta ‘Green Pie Crust’ has
striking fall color. We will definitely
divide and share some of these!

We have some special trees and shrubs at our house and we were thinking it would be nice to share them. Gardeners do this all the time with friends and family or if they are moving to a new home and want to take some of their special plants with them.

In many cases, this isn’t too difficult to do – especially with perennials. Depending on the species, perennials can simply be dug and moved to their new location. Some of course have special timing requirements; for instance peonies should only be moved in the fall after they are dormant and hosta are best dug and moved in the spring. If you can’t get them in the ground right away – no problem, just pot them up. Most perennials will hold for months until the time is convenient for planting.

Certain perennials like daylilies can be dug, divided, and kept as bare root plants in cold storage for quite a while without harm.

Things get a little trickier when it comes to moving trees and shrubs. Generally, trees and shrubs should be transplanted when they are dormant. This could mean late fall, winter, or early spring. Obviously digging cannot happen when the ground is frozen; but plants should also not be dug when the ground is soggy. Digging plants in wet soil can increase the damage to the small roots that are so important for water and nutrient absorption.

We will root prune this young holly in a few weeks and dig it and pot it up in the spring.

We will root prune this young holly
in a few weeks then dig it and
pot it up in the spring.

Most deciduous trees and shrubs can be moved in the fall or spring but evergreens should be moved in the late winter or spring if possible. This is because evergreens lose water through their leaves during the winter and since many of the small water absorbing roots are removed or damaged when a tree or shrub is dug, the remaining root system may not be able to absorb enough water to replace the water that is lost. This can result in excessive winter damage.

Moving trees and shrubs when they are young and small increases the likelihood of success. The older they are, the more extensive their root system and the larger the root ball has to be.

The size of the root ball is determined by the spread of a shrub or the diameter of the trunk at chest height for trees.

  • For shrubs, you should have a minimum of 6″ of root ball for each 12″ in spread. If you can handle a larger root ball, even better.
  • For trees, you should have a minimum of 12″ of root ball for every 1″ in trunk diameter. Trees with a trunk greater than 2″ in diameter will require a huge root ball and will be very difficult to dig and move without professional help.

Here are a few tips for digging trees and shrubs.

Root Pruning

When you are moving an established tree or shrub, you will increase your chance of a successful transplant if you root prune in the spring or fall prior to digging. We will be doing this for the little trees we are planning to dig next spring. Root pruning encourages the formation of new feeder roots and reduces transplant shock when the plant is eventually dug and replanted. Root pruning should only be done when the tree or shrub is dormant; after the leaves of deciduous trees have dropped in the fall or before bud break in the spring.

There are two methods of root pruning – spading and trenching.

This young maple seedling should transplant well

This young maple seedling
should transplant well

Spading is the simplest method and is sufficient for small/young trees and shrubs. It involves using a sharp spade to cut straight down through the soil about 12″ deep around the entire tree or shrub. This should be done a few inches closer to the trunk than the size of the root ball you will eventually dig. This slices through the roots and stimulates the growth of new feeder roots. Be sure that the spade you use is sharp so it makes a clean cut.

Trenching involves more work but is the better method to use when you plan to move larger, more established trees and shrubs. With this method, you basically dig a 12″ – 14″ deep, 6″ – 8″ wide trench around the tree of shrub. The outer edge of the trench will define the outer edge of the root ball. After the trench is completed, backfill the trench with a mixture of the native soil and some good quality compost. Feeder roots will develop and grow into this loose soil. It may take a while to get good root production throughout the trench so you may want to do this a year in advance of moving the tree.

After root pruning (regardless of which method you use), water the tree or shrub well, apply a good organic fertilizer like Espoma Plant-tone or Holly-tone,  and mulch with 3″ of a good quality organic mulch. Be sure to provide water as needed until the plant is dug.

Paperbark maple gets its name from the interesting exfoliating bark.

Paperbark maple gets its name from
the interesting exfoliating bark.

The trees we will be digging are still pretty small so we will just root prune using the spading method. They haven’t dropped their leaves yet so we will need to wait a few weeks before we do this.

Acer griseum (paperbark maple) is one of the trees we are going to transplant. This tree was given to us by a very good friend and there are two nice seedlings that have come up under the tree. Acer griseum is a very attractive small maple that grows to about 20′ – 30′ tall. It has beautiful exfoliating bark that is cinnamon colored and smooth underneath.

Beautiful fall color!

Beautiful fall color!

The leaves are three lobed with a delicate texture and the fall foliage is spectacular turning the tree into a flaming red color in most years. It is one of the last of all the maples to color up in the fall and is a really cool tree to have!

Another one that we want to share is one of the purple-leaved smoketrees, Cotinus coggygria. There are several purple-leaved cultivars and I’m not sure which one this is but it has beautiful foliage color from spring through fall.

The color has now begun to fade but last week this Cotinus foliage was beautiful

The color is now fading but last week
this Cotinus foliage was beautiful

The oval leaves are purple through the summer and turn a nice burnt orange in the fall.

We noticed that a few of the lower branches have self-layered creating several small plants that we will be able to dig up in the spring.

A few small hollies that are the perfect size for transplanting have come up here and there in our woods. We will be digging a few of these as well!

It will be cool to share a few of our favorite trees with our family – luckily they are hardy up there.

 

Think about sharing some of your own special plants. They are the perfect gift from one gardener to another!

Until next time – Happy Gardening!

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Native dogwoods have beautiful fall color

The trees are donning their brilliant fall colors, the fields of corn and soybeans are being harvested, the last tomatoes and beans are being picked from the garden – fall is here!

pruning with hand shearsThese beautiful, crisp, cool days of autumn are when we begin to put our gardens to bed for the season. This has many gardeners venturing out with shears in hand to primp and prune and otherwise tidy up in the garden.
While it is a great idea to cut back some of your herbaceous perennials in the fall, you should keep your pruning shears and loppers away from your trees and shrubs for a while yet.

Why? Because pruning stimulates regrowth. Plants respond to pruning with a burst of new growth; the more severe the pruning, the heavier the regrowth. If this growth occurs during the warm days of fall, the tender new shoots that develop will not have time to harden before the winter cold sets in and they become prone to winter damage.

A majestic oak silhouetted against the winter sky

A majestic oak silhouetted
against the winter sky

In general, woody plants should be pruned when they are dormant. This usually means in late fall, winter, or early spring.

How do you know when trees and shrubs are dormant?

It’s easy enough to tell when deciduous trees and shrubs are dormant because they lose their leaves but it’s not as clear cut with evergreens since they keep their leaves through the winter. Luckily, evergreen trees and shrubs normally enter dormancy in the late fall around the same time as deciduous plants.

Not all pruning is done during the dormant period

Pruning quince at the wrong time leads to loss of bloom

Pruning flowering quince at the wrong
time leads to loss of the bloom

Though trees and shrubs can always be pruned when they are dormant, there are good reasons to delay pruning of some species. This is especially true when it comes to the spring flowering trees and shrubs. If you prune these during the dormant period, you will be removing many if not all of the flower buds and this will obviously impact the spring bloom!

Many gardeners are tempted to prune their trees and shrubs in the fall as part of their fall clean-up chores – to tidy up scraggly looking or overgrown plants. Before you cut (even if they are dormant), it is important to think about when they flower and the age of the wood that produces the flowers.

Spring blooming shrubs like rhododendron should be pruned after flowering

Spring blooming shrubs like
rhododendron should be pruned
right after they finish flowering

Generally, trees and shrubs that flower in the spring form their flower buds in the previous season, usually in the late summer or early fall. These plants flower on “old wood” or growth that was produced the summer before. Because the flower buds are already set on the branches, you should try to avoid pruning them in the fall, winter, or spring. Shrubs like azalea, rhododendron, lilac, some hydrangea, forsythia, viburnum, and trees like dogwood, redbud, and crabapple fall into this category.

The best time to prune these spring bloomers is right after they finish blooming. Pruning at this time can range from simple deadheading of spent blooms to heading back branches and thinning to reshape or reduce the size of the plant. Here are some tips for pruning spring blooming shrubs.

American holly tree after severe pruning

American holly after severe pruning

The exception to this rule is if you want to do any heavy pruning. Severe pruning, including rejuvenation pruning where you might cut a shrub down to 12″ to 24″ or lower, should be done when the plant is dormant – usually in March. Obviously you must sacrifice the bloom for that season and possibly the following season as well but in most cases, you will be rewarded with a beautiful “new” shrub. Not all shrubs can be pruned hard like this so be sure to do some research before you start chopping!

Summer flowering trees and shrubs form flower buds on the new growth that is produced in the spring and summer. These are normally pruned in the spring before growth begins. However in colder regions, we often recommend that you delay pruning until the threat of very cold weather is past. This sometimes means pruning after growth has begun but don’t worry, it won’t hurt the plant.

Summer pruning

Summer is a good time to prune certain trees and shrubs if you don’t want to encourage a lot of new growth. As I mentioned earlier, pruning stimulates growth, especially when it is done in the spring. Pruning in summer has a dwarfing effect because growth is slower at this time.

This Kieffer pear was pruned in winter. This resulted in vigorous water sprout growth.

This Kieffer pear was pruned in winter.
This resulted in vigorous water sprout
growth in the spring.

For instance, summer is a great time to prune water sprouts – those vigorous stems that grow straight up parallel to the main stem. Pruning them out in the summer can reduce the number of water sprouts that will develop the following season.

Summer is also a good time to prune trees that are heavy bleeders like maple, birch, and dogwood. It is best to avoid pruning these trees just before and during active growth in the spring because they have a heavy sap flow at this time.

A good pruning book will give you recommendations on the timing and techniques for pruning specific trees and shrubs. A handbook like this is a valuable addition to your gardening library.

For more pruning tips, visit our website.

Until next time – Happy Gardening!

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