Which plants you should prune back in the fall

 

For some reason, the fall season is when many gardeners get the itch to prune back plants in their gardens.  The guidelines are as follows, at least for our zone 4 to 5 gardens here in Ottawa, Ontario:

  • if a shrub blooms early (before June) wait until after flowering to prune.  Some examples of early bloomers that need that old wood to bloom on are lilacs, forsythia, bridal wreath spireas, sand cherries, weigela, ninebarks, rhododendrons, viburnum, cranberry bushes, flowering dogwoods and magnolias.
  • if the shrub blooms after June, it can be pruned back in the fall or in the early spring when new growth is visible.  Examples include Snowball and PeeGee Hydrangeas, spireas (except for bridal wreath), Butterfly bush, smoke tree, hibiscus (rose of Sharon), and red stemmed dogwoods.
  • woody shrubs like boxwoods, junipers and cedars can be trimmed back in the fall too, but also throughout the growing season (spring and summer)
  • some shrubs are best pruned while dormant. (late fall to very early spring, late February to early March)  These include barberries, smoke bush, crepe myrtles, spireas (except bridal wreath variety), dogwoods, and cotoneasters.
  • to rejuvenate shrubs that flower poorly, are overgrown or straggly, cut them back to just above the first bud above the soil while the plant is still dormant.  Shrubs that do well with this drastic treatment include spireas, lilacs, ninebarks, forsythias, barberry, weigela, blue mist, forsythia, honeysuckle, and potentilla (cinquefoil).  You may sacrifice the flowers the first season after this rejuvenation, but the plant will be healthier.
  • deciduous (non-evergreen) trees are best pruned when dormant (late winter) as well.  It is much easier to see the structure of the tree before the leaves come out.  Winter pruning also prevents the formation of bacteria and disease in the cuts. The wounds will heal quickly as new growth starts shortly after pruning.
  • dead branches can be cut off any time in the season.
  • after the first frost, remove any leaves from roses and apply mulch to the crowns. This prevents the plants from heaving from the ground during freeze/thaw cycles. You can cut the longs stems of the most tender floribundas, hyrdrid teas and grandifloras back to 20 inches before winter too to prevent them from breaking off under a heavy snowfall.  Another tip for tender roses is to apply a collar around the bush and fill it (loosely) with leaves.  Wait to prune others back until daffodils start to bloom in the spring to ensure the ground temperature is sufficiently warm.  Dead or broken branches can be cut off in the fall or any other time of the season.  Suckers can also be removed in the fall, cutting them out as close to the base of the plant as possible.

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Perennials can be, but do not have to be, deadheaded (remove dead blossoms) and cut back in the fall.  Remove sturdy flower stalks (coneflowers etc) right back to the foliage at the base of the plant.  Some gardeners like to leave these stalks on the plants over the winter for birds and their snow-covered beauty.  On softer plants simply remove the browned and dead looking, limp or soggy foliage (daylilies, peonies, bleeding hearts etc) and cut back their stems to six or eight inches from the ground.  I like to do everything I can in the fall because spring seems to be so short lived these days and I run out of springtime hours in the gardens.  Whenever you clean up your gardens, remember to harvest the seeds for future (freebie) plants as I did for my cottage garden.

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pictures from Pexels and Pixabay

Mirror mirror on the wall…

Instead of “mirror, mirror on the wall”, I should say “gardens, gardens on my route,  who’s the fairest of them all?”  I know that “all” does not rhyme with “route”, but let me ensure you get the picture, literally…. Continue reading

The reason you should not prune some shrubs in the fall

In a recent post I listed many shrubs categorized by when you should prune them.  The reason you should not prune many shrubs in the fall is because you will remove most of the buds that will turn into flowers the following spring.  Examples of these buds are shown here in magnolia, rhododendron and forsythia shrubs…

 

If you must prune these shrubs to control their size, wait until after they bloom in the spring to do so…

please be sure to visit my slightly more humorous blog YOUR DAILY CHUCKLE  It is guaranteed to make you LOL.

Pruning Shrubs

                                                                            

The rule of thumb for pruning or cutting back shrubs is this:  if it flowers before June, cut it back immediately after flowering.  If it flowers after June, cut it back first thing in the spring.  The reason for this rule is because spring blooming (before June) shrubs form flowers on the previous years’ growth, so if you cut it in the spring you will be cutting off the stems that will be producing flowers that season.  Shrubs grown primarily for their foliage (dogwood, burning bush, dappled willows etc) should be pruned in the early spring, before new growth starts.

Spring pruning  (just as growth starts)

  • late blooming (pink) spireas
  • peegee hydrangeas
  • burning bush
  • late blooming clematis
  • holly, very early, while still dormant
  • rose of sharon
  • late blooming heathers
  • cotoneaster (minimal)
  • yew, before new growth starts, then several times during season
  • weigelia
  • late blooming lilacs
  • shrub roses
 
         
             
After flowering:
  • early blooming clematis
  • rose of sharon
  • sand cherry
  • mock orange
  • rhododendrons
  • magnolias
  • early heathers
  • barberry
  • early blooming (bridal wreath) spirea
  • forsythia
  • most lilacs
 
Pruning in the fall can cause new growth that is stimulated by the pruning to be damaged by cold weather. Fall pruning will also remove late forming buds that will produce flowers the following spring.  For these reasons, pruning is best done in spring or summer.   Dead, diseased or crossing branches however, can and should be pruned as soon as they are discovered.

Plants of the week from Gardens4u, take five

These are my favourites for this week…

Traditional perennials: hostas

hostas are great at the front of a border or bed and thrive in deep shade through part sun.  Most hostas prefer shade, but those with yellow leaves or fragrant flowers prefer more sun.  They come in many colours and sizes these days from miniature to huge.  If you do plant the large ones, be sure to give them lots of space as they do not look their best when crowded.

Modern perennials:  geraniums, not the red annual type your grandmother planted, but the perennial variety

Perennial geraniums also look great at the front of borders or beds.  They tolerate shade and part sun.  I love them because they are the first to green up in the spring, offer some colour with the blooms, but look great even when not in bloom.  They come in many colors and sizes.  Some of the larger ones can tend to be floppy, so I stick to the smaller ones.

Shrubs: Black Lace Elderberry

The deep wine colour of Black Lace Elderberries look wonderful mixed with all of the shades of green in your gardens.  They die down to the ground each winter in my area, and are often slow to come back in the spring, but can grow to heights of six feet or more. This spring was so late and the winter so cold, I thought my black lace had died.  Thankfully I decided to give it another week, and sure enough, one week later it was one foot tall!  The pale pink flowers are pretty but I consider them a bonus as they don’t last long.  The dark coloured lacy foliage is the reason I love this shrub.  This season it is a great backdrop for my lily trees featured in the third picture.

Vines:  Silver Lace

Although the Silver Lace vine blooms in the fall and so not blooming this week, I am always suggesting it to my clients.  It is quick growing, covering any structure very fast with white lace like flowers, a beautiful sight in September through November.  Unfortunately I lost mine this past winter due to the severe cold weather we experienced.  It is only hardy to zone 5 which is pushing the envelope for my Ottawa garden.

Annuals: Coleus

Coleus are great for filling in blank spots and contributing splashes of colour in shady spots of your gardens.  I never used to like them, but after seeing them tucked in among perennials in a client’s garden, I’ve changed my mind and added some to my own gardens this year.  Coleus come in many combinations and shades of pink, red and green; all make vibrant additions to a garden or container.

Stay tuned for next week’s choices…

Plants of the week from Gardens4u, take three…

Here are my favourite plants this week…

Traditional Perennials: Asiatic Lilies

Asiatic lilies (also known as tiger lilies) come in many colours and heights.  Unfortunately I had to give up on them years ago as japanese beetles demolished them every season.  I now plant the lily trees featured below, same beautiful bloom, just sturdier and taller stems.

 

Modern Perennials:  Lily Trees

Similar to the more traditional asiatic lilies in appearance and bloom time, lily trees have much stronger stems which makes them more resistant to the japanese beetles that devour the former plant.  Lily trees grow to six feet in height by their third season and boast impressive blooms. Every years more and more color variations are available.

Shrubs:  Hydrangea

Hydrangea bushes have beautiful bloom in white, pink, blue and even mauve.  There are several varieties to choose from.  The most common is the “snowball” or Annabell type with round blooms that start off pale green in color and change to white.

The pale pink, blue and mauve flower heads belong to the mophead variety, with the color depending on the acidity of the soil it is planted in.  For blue blooms slightly acidic soil is required to allow aluminum in the soil to make the blooms blue.  Aluminum sulphate can be added to the soil for this purpose.  Fertilizer low in phosphorus (middle number on fertilizer packages) and high in potassium (last number on packages) will ensure blooms are blue.  For pink blooms slightly alkaline soil is required to prevent any aluminum from making the blooms blue.  Adding lime to the soil will increase the pH (make it alkaline) to prevent the soil from absorbing aluminum.  Adding fertilizer high in phosphorus (the middle number) also prevents aluminum absorption.    If you have trouble making your soil the right pH for the color of blooms you desire, consider planting the hydrangea in a pot where the soil pH is easier to control.

PeeGees or paniculatas have cone shaped, pale pink flower heads and come in tree form as well as bush form. Oakleafs have leaves shaped like those on an oak tree and have cone shaped white blooms that turn to pale pink.

Vines: Ivy

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There are many types of ivy to grow; my favourite is the Boston ivy that covers my back deck, creating my “green room”

 

Annuals: Million Bells

 

My favourite cascading annual for containers is called Million Bells.  They come in many colors, be sure to choose contrasting colours for your containers like the orange and purple above.

 

Stay tuned for next week’s picks…

 

Plants of the week from Gardens4u, take two…

These are my favourites this week…

Traditional Perennials: Roses, roses and more roses…because, in my opinion, you can never have too many roses…

Roses come in many colors and growth habits; climbers, shrubs, bushes and even trees.  They look awesome climbing a wall or fence, at the front of a perennial border, or towards the back of a large bed.  Although I have them under the traditional perennial category, the modern versions are much hardier and require less maintenance to keep them looking beautiful year after year.  With the exception of the yellow shrub rose pictured that only blooms for about one week, the other roses, especially the shrubs, in my garden bloom from June right through to a hard frost.  A few years ago the white one was still blooming in November!

Modern Perennials:  Goats Beard or Aruncus or Wild Spirea…

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I have only seen Goat’s Beard with white blooms, it is new to my knowledge base.  Please let me know if it comes in other colors too, it is absolutely striking!  In addition to the towering version shown here, it apparently comes in a dwarf variety as well.

Shrubs:  Weigela

The weigela in my garden is in tree form (right), although the bush form is much more common.  The tree form fits into the back of a border, especially in front of a fence, or veranda in this case.  One of my clients once talked me into cutting his weigela bush right back to about one foot tall because a backhoe was scheduled to work on his pool area and he thought the bush would get ruined.    I did cut it back, but was worried as the bush must have been six feet in diameter and five feet in height: spectacular.   I wish I had taken a picture of it to show you before and after the pruning.  It did survive the drastic hair cut, but is not quite as large yet two years later.

Vines:  Clematis

Clematis vines come in many colours too, from white to yellow to pink or blue and many shades of purple; all are beautiful ways to cover a wall or fence.  Some blooms are flat, singles and others have raised centers (doubles)  I have two that climb through a tree.  Unlike other vines, they will not damage a tree as their stems are very light, almost fragile.

Annuals:  Pansies

Pansies look like tiny, cheerful faces to me; I love them in containers of any kind.  They too come in many colors, although I do tend to go for the purple ones.

Stay tuned for next week’s picks…