These gardening tips first appeared in the Van Bakel Garden Center monthly newsletter - full of climate specific gardening advice for the Newmarket area.   Scan the index to the right for particular topics.

Correct Planting for New Trees and Shrubs.
(from May 1st, 2009 newsletter). 
Container sized shrubs can be planted at any time of year, but in the cool weather of spring before they’ve leafed out is a particularly good time for planting.  (Early Fall is probably the best time, but by then all the really nice things are long sold out!)  Planting during the heat of summer is OK too as long as a few precautions are taken such as watering REALLY well and often for the first 2 weeks in the ground, and shading them from the sun for a week or so after planting.  Here’s the steps to sure success when planting new container grown trees or shrubs -

1)  Wet the entire root ball thoroughly.   The soil container grown shrubs are potted in is very high in organic matter and dries out quickly - sometimes to the point where it actually sheds water like a completely dried out sponge would do.  Combined with this, roots are often so congested that it becomes difficult for water to penetrate to the center of the root ball.  Normal watering with a hose doesn’t always penetrate this combination, so I always recommend immersing the whole container in a large bucket of water for 5 minutes or so, or until air bubbles stop rising to the surface, to make sure ALL roots are well saturated.   (THIS IS PROBABLY THE #1 REASON FOR NEW SHRUB FAILURE – insufficient water within the congested root ball at planting time.   Watering after planting doesn’t ever get into a congested root ball and the shrub goes through enough stress to sometimes completely collapse and die out in the burning sun.).

2) While your shrub is soaking in the bucket prepare the planting hole by digging a hole about twice the diameter of the container but no deeper.  Loosen the soil at the sides and bottom of the hole and mix some compost into the soil that you’ve loosened and into the soil that you’ll be filling back into the planting hole - approx. 75/25 soil to compost is the goal.  No fertilizer at this point, but if you don’t have compost, a handful or two of bonemeal mixed into the backfill will do.  Water the planting hole well and wait for it to drain away.
3) Remove the plant from its container by turning the pot upside down while securing the base of the plant with your palm. Try not to pull on the stems but instead tap or wiggle the sides of the container until the root ball slides out.   Tease away some of the roots from the root ball if you can do so without too much damage.  If it’s very congested though, cut through some of the larger roots or make a ½” deep slice at 3 or 4 spots on the surface.   Now, one last dip into the bucket before putting it into the ground.

4)  Place the shrub into the hole spreading out any roots that you’ve managed to tease away and start backfilling with the amended soil.  When half full, tamp down firmly on the backfill snugging soil close to the roots.  Never push down on the roots themselves, push on the soil surrounding the roots.  Fill the hole up to the base of the stems without covering the original root ball surface and again, firm the soil well around the roots.  Overall, the planting hole depth should result in your shrub’s stems being at or slightly above the surrounding soil surface after it’s been firmed into place.  If for some reason you’ve ended up deeper than this, get underneath the root ball with your shovel and jiggle it higher and refirm the soil around the root ball.  Trees and shrubs planted too deep is the #1 cause of shrub failure or disease problems in subsequent years.

5)  Mulch with a 1” layer of compost or chopped leaves up to 2” away from the stems.  Never pile mulch around the stems themselves. 

6)  Immediately water deeply to further help soil settle into place in close contact with the roots.  For at least one week, watering deeply every day is important since feeder roots have been damaged in the planting process and for just this short period of time your new shrub needs your help - it just doesn’t have the ability to reach out into the soil for water yet.  This changes quickly though, so after a week, watering just once a week for a month will establish your shrub well enough that it can start looking after itself.  Give it some watering attention during any drought in its first year by placing a hose at a slow dribble by the base so that it can soak deeply into the root ball.  An important tip when planting evergreen shrubs like cedar, Juniper, Boxwood, Holly… – during the first week, shade them from the sun by simply draping them with a light fabric anchored by a few stones to keep the fabric in place.  This will prevent leaves and branches from burning in the sun before feeder roots are functioning again.  (This is good practice when planting any shrub in the heat and burning sun of high summer too)

7) Once you see signs that your shrub is happy in its new home and is putting out new growth, soak it thoroughly with a water soluable “plant start” fertilizer mixed to half the recommended strength (10-52-10). 

 With all of these steps taken, it’s virtually a 100% guarantee that your container grown shrubs will bounce into a happy life in your garden with minimal die-back.  All of these same planting rules apply to trees as well.  Sometimes a few branches may die, but this doesn’t mean the shrub is dying – it’s just a bit of transplant stress.  Just prune away the dead branch down to a lateral and all will be well. 

Weigela florida ‘Eyecatcher' (from March '09 newsletter)
 Plant breeders have been paying a lot of attention in recent years to the genus Weigela, and this spring we’re bringing in yet another great new compact cultivar - Weigela florida ‘Eyecatcher’™.  Plant breeder David Tristram of England earns the kudos this time for this wonderful new combination of electric yellow and green variegated foliage and dark rose-red flowers, a vibrant combination that’s particularly useful to brighten shady spots where it prefers to be.   

Dark rose-red flowers for spring and bright yellow foliage all summer on a compact shrub makes it perfect for mixing with perennials unlike some of the larger members of this family.  A large blue leaved Hosta, for example, would contrast beautifully with the yellow foliage.  At only 18” to 24” ‘Eyecatcher’ can be tucked in anywhere without overwhelming or crowding other plants. Partial or filtered shade is a must for the richest foliage colour, and attention to correct pruning will keep it compact and healthy.  

Weigela of any variety don’t tolerate drought well, so make sure your new ‘Eyecatcher’ is planted somewhere where there’s the best chance of consistent moisture.  Lots of compost in the planting hole and generous mulch will help it thrive in drier spots.  Pruning is best done immediately after flowering and should concentrate on removing one or two of the oldest stems down to the base of the plant to keep it from becoming choked and to encourage strong new stem growth.

Dwarf size and compact growth make these two Weigelas a great choice as a centerpiece in a large planter.  Even after finished blooming, Eyecatcher’s gold foliage, or My Monet’s pink tipped foliage make an all season colourful backdrop for a ring of annuals or trailing vines.  Why not give ‘Eyecatcher’ a try in your container planting this year!  (For large containers, our planting team can bring everything necessary to your home and plant them up where they sit.)

Golden foliaged shrubs can be a designer’s delight.  Weigela ‘Eyecatcher’ and Cornus alternifolia (Pagoda Dogwood) ‘Golden Shadows’ (more of a small tree than a shrub), are two good choices to brighten shady spots.  For sunnier positions try Cotinus cogygria (Smokebush) ‘Golden Spirit’, a brilliant solid yellow, large leaved, upright shrub that thrives in drought (gorgeous fall colour too).  For something of smaller stature, Caryopteris incana ‘Sunshine Blue’ carries amethyst blue flowers in late summer at the end of stems covered with small bright yellow foliage, and also does best in a sunny dry spot.  (Prune Caryopteris hard back in spring for best compact form and to encourage strong flowering growth.).

Hydrangea ‘Twist ‘n Shout’ (from February '09 newsletter)
One of the plants we’re excited to bring you this spring is Hydrangea ‘Twist ‘n Shout’, a new lacecap Hydrangea in the Endless Summer® series.  Like the original ‘Endless Summer’, ‘Twist ‘n Shout’ blooms on new wood unlike other H. macrophyllas, which means you’ll enjoy the full force of it’s vigorous blooming power for most of the second half of summer. (Read more about new wood / old wood blooming habits below in "Correct Shrub Pruning...".) As though this weren’t enough, the stems are bright red all season holding deep green leaves that turn a beautiful mix of yellow, rosy red, & purple in autumn.  WOW!  For 2009, its introductory year, only limited quantities are available.  Don’t miss out on this fabulous new flowering shrub!   

What exactly all the excitement about?  What makes the Endless Summer® Collection so noteworthy?  Well, it is the result of many years of hybridizing efforts in the Hydrangea family that resulted in a successful cross between H. macrophylla and H. arborescens that brought the large pink flowers of H. macrophylla together with the new wood blooming habits of H. arborescens to produce a whole new hybrid species.  The trademark name ‘Endless Summer Collection’ is still under patent protection, so we have to pay more for any of the plants from this exciting new hybrid group but they’re worth every penny because of their outstanding garden performance. 

Correct Shrub Pruning starts with knowing what you’re pruning!  (from February '09 newsletter) 
While we’re talking about Hydrangeas, I’m going to take this opportunity to answer our most often asked question –  
               “Why doesn’t my Hydrangea bloom?” 
Like most shrub blooming problems, the answer lies in correctly timed pruning.  The very first bit of information about any shrub that’s essential to know before pruning is “does it bloom on old wood, or does it bloom on new wood”?   

Hydrangea arborescens ‘Annabelle’ is the sturdy plain-white-fading-to-green-then-tan Hydrangea that remains one of the most reliable landscape plants for virtually no-care performance.  Why is it such a reliable bloomer?  Because it blooms on new wood which means even in the harshest winter when stems are killed (or pruned) to the ground, the new spring growth will set flower buds and bloom the same year.

The other type of Hydrangea with large pink or blue blooms are from a different branch of the Hydrangea family - Hydrangea macrophylla, commonly called “florist’s Hydrangea”, and growing them well is nowhere near as carefree. Why so difficult?  Because all H. macrophylla bloom on old wood.  We see them in glorious bloom at the garden center and, of course, expect them to do just the same in our garden - but what happens? …  “The stems and leaves grow strong each spring, but don’t produce blooms !?” The answer lies in a simple bit of basic botany that dictates the blooming habits of all flowering shrubs.  Some shrubs set flower buds and then continue immediately on to the blooming phase on the current season’s new stems – in other words, they bloom on new wood.  Other shrubs also set flower buds on the current seasons growth but are genetically geared to stay dormant over winter and wait until spring before moving on to the blooming phase –  in other words, they bloom on old wood.  Why does your ‘Annabelle’ Hydrangea arborescens bloom reliably each year, but not your H. macrophylla  ‘Nikko Blue’?   Simple - H. arborescens blooms on new wood, but H. macrophylla blooms on old wood - they are two completely different shrubs although from the same family.

Common confusion lies in the fact that because they are both Hydrangeas it is expected that they both behave the same, but they need to be thought of as completely different plants.  H. arborescens behaves like a Rose of Sharon or a Rose for example by blooming on new wood, whereas H. macrophylla behaves like a Lilac or Forsythia which blooms on old wood.  (Lilac’s stems and flower buds are cold hardy however. H. macrophylla’s are not.). 

Here’s a guide to the most popular branches
of the Hydrangea family –

Hydrangea paniculata –  blooms on new wood so can be pruned hard back as much as needed in early spring before growth begins.  With skillful pruning and patience it can grow into a small tree since it has very sturdy stems.  Some common cultivar names are ‘Pee Gee’ ‘Kyushu’, ‘Limelight’, ‘Quick Fire’ … 

Hydrangea arborescens – blooms in new wood so can be pruned hard back as much as needed in early spring before growth begins.  The stems aren’t as sturdy as H. paniculata though so it will remain a bushy shrub.  This is the old fashioned reliable favourite sometimes called "smooth" Hydrangea, with the most common cultivars being ‘Annabelle’ or ‘Grandiflora’  

Hydrangea macrophylla – blooms on old wood.  Often called the “florist’s Hydrangea”, with large pink blooms in either a mophead or lacecap form.  There is a huge list of cultivars but the most familiar one is 'Nikko Blue'.  Same bloom habits as Lilac but while H. macrophylla's roots are cold hardy in our climate, it’s stems are not, so the buds that form one year don't make it over our winters to bloom the next.  New growth comes again from the roots, but no flowers.
Starting to see the pattern? 
When to prune completely depends on this new wood / old wood question.  Just a bit of logical thinking will take you from there.  Here’s some examples. 

Prune a Lilac in late fall or early spring and you’d be pruning away the flower buds since it blooms on old wood – it will put out strong new stem growth though and set flower buds that will bloom the following spring.  Lilac should therefore be pruned immediately after flowering.  Prune a Rose of Sharon in late fall or spring and you’ll spur on strong growth that will set buds and flower later the same year since it blooms on new wood.  Excellent!  Spirea x bumalda ‘Goldflame’?...blooms on new wood so pruning in late fall or early spring encourages strong current season bloom.  Spirea x vanhouttei ‘Bridlewreath’ however blooms on old wood so prune this spirea immediately after flowering so that the resulting strong stem growth has a chance to set new flower buds for next year. 

Pay attention to which species (e.g. arborescens) within a larger genus (e.g. Hydrangea) each shrub is, and then just a tiny bit of research or observation will answer the key question – does this particular shrub bloom on old wood or new wood?  (chances are that if the shrub blooms before the end of June it blooms on old wood.)  If it blooms on old wood, is it flower bud hardy, or only root hardy?  (e.g. Lilac is root & flower bud hardy, but many Rhododendron’s are only root hardy.).  The species name should always appear on the plant tag - often in the fine print, but it should be there.  It's the word that is italicized and not capitalized.  That’s the word that leads you to the exact plant at hand.  If the species name isn’t on the tag, ask our staff.   Without the species information you just can’t be at all sure what plant it is or how to care for it.  

Hope this focused woody plant botany lesson helps with your pruning mysteries this year. 

Physocarpus, aka Ninebark
(from August 2010 newsletter )

Vigorous and drought tolerant, Ninebark is an easy shrub for just about any type of soil, in full sun to partial shade.  In only 3 – 4 years after planting it has the strength to start stretching new stem growth up 8 – 10 feet each season with a branching habit that is up and out in a vase like shape.  The upper half of the branches, when loaded with blooms in spring, bend down to almost touch the ground in an elegant fountain-like display.   

In other words – it needs lots of room to strut its best stuff!   

When the blooms fade there’s a second show of deep red seed heads that is almost as attractive as the flower show.  Combined with their ever present dramatic foliage colour, how many other garden shrubs can you name that contribute so many ornamental elements! 

The only maintenance necessary to keep Physocarpus looking its fountaining best is in early spring when it is good practice to remove ¼ of the oldest stems at the base to make room for all the vigorous younger stems that have the best blooming power.  Ninebarks bloom on the previous season’s growth though so the remaining ¾ of the branches should be left unpruned since they hold the flower buds that will bloom later in spring.  After blooming, these branches can be cut hard back if necessary so the new growth that pruning stimulates will have time to set flower buds for next year.  On a healthy established Ninebark new stems grow 6’ – 8’ in a single season so while the shrub may look a little bare after ¼ of the oldest stems are removed, it will fill in quickly.  (This is the same pruning regimen for all multi-stemmed spring blooming shrubs.).  

There are many lovely cultivars to choose from for unique foliage colour impact, but all require the same elbow room and correct pruning for a spectacular flower show and elegant growth habit.  P. ‘Dart’s Gold’ is a mass of sunny yellow leaves;  P. ‘Coppertina’ is a unique bronzy/burgundy colour that goes will with the many small Spireas with coppery red tones;  P. ‘Summerwine’ is a rich burgundy wine colour.  Give any one of these great foliage shrubs a try for a dramatic spring show each year. 

‘Miss Kim’ Lilac, a great semi dwarf Lilac with full fragrance and fall foliage colour.  (from June 2010 newsletter) 

Following through on the above advice, now is the time to plant for spring interest.  Not only will the plants have plenty of time still this season to strengthen roots and set a few flower buds by Fall to overwinter for spring blooming, but the gaps in your garden or nice plants you’ve seen elsewhere are still fresh in your mind.  

Among spring flowering shrubs, Lilacs are probably the first to come to mind.  The classic hybrids, most varieties of Syringa vulgaris, have fallen out of favour in recent years though because of their prolific suckering and tatty appearance once they inevitably get powdery mildew disease.  High maintenance and low on garden contribution.  Beautiful fragrant flowers, yes, but that’s just a two week contribution to your garden scheme out of the whole year.   

Many gardeners assume that all lilacs are prone to these problems.  Not so!  For larger gardens there’s many beautiful cultivars in the Syringa x prestoniae hybrid group, and a handful of dwarfs for smaller gardens from the S. meyeri or S. patula group that are readily available.  No suckering, no powdery mildew.  One real standout among these trouble free Lilacs is Syringa patula ‘Miss Kim’.  This dwarf cultivar (matures at 8’ only) is also one of the very few Lilacs that has attractive fall colour for an additional contribution to an all season design.  Most other lilacs just fade out and drop in autumn, but S. ‘Miss Kim’ turns a lovely smokey wine red that looks terrific among the golds and tans of ornamental grasses.   

What about fragrance you ask?  One of the best!  When the lavender / pink buds open up to a soft light pink, an entire garden is filled with a delicious spicy scent that is among the best any type of Lilac can offer.  At the Van Bakel greenhouse working among many competing fragrances, ‘Miss Kim’s’ beautiful spicy scent stands out.  Another bonus is its slightly later flowering time.  While other Lilacs are finishing, ‘Miss Kim’ is just starting to bloom for a prolonged Lilac season.

Like all Lilacs, S. ‘Miss Kim’ needs a full sun position to flower at its best but in partial shade it still performs well.  Growth habit is compact and upright with glossy deep green leaves that look fresh all season making it a perfect backdrop in a perennial border.  Let it grow to its full potential size of around 8 feet, or it takes pruning well if you need to keep it at a smaller size.  Either way ‘Miss Kim’ is much more attractive than S. vulgaris during its non-flowering phase. (As with all Lilacs, early June, right after flowering, is pruning time.  This allows for the resulting new growth to set flower buds before winter dormancy sets in.). 

Index to
"About Shrubs" articles

Planting New
Trees & Shrubs

Weigela florida 'Eyecatcher'

Correct Shrub Pruning Starts with knowing what you're pruning!

Hydrangeas

Physocarpus, Ninebark

'Miss Kim' dwarf Lilac