Barking up the Wrong Tree

Oct21

They say dog is man’s best friend – well how about dogwood is gardener’s best friend? I don’t mean the graceful dogwood trees, Cornus kousa or Cornus florida – I wish I could say I was referring to them, but sadly no, we can’t grow these lovely trees in our zone 3, chinook-challenged climate. We can however, grow some splendid cultivars of our native Cornus sericea (red osier dogwood), and the closely related Cornus alba (Tatarian dogwood). I recall a recent quip from an out-of-province industry professional in reference to these…….he snorted, “That’s a dogwood? Where I come from dogwoods are trees.” Yeah, yeah, I know – we’re horticulturally deprived here. But no need to feel sorry for ourselves – the dogwood shrubs I speak of, though not as ornamental in flower, have special characteristics that set them apart from their arboreal counterparts. Not only are they extremely hardy in our fierce climate, they have a beauty all their own and offer it up year round.

Let’s take a walk through the seasons and see what these dogwoods have to offer

Winter Bark

Both species have colourful bark which is very showy in winter. C. sericea has dark red bark, C. alba has brighter red bark, and each have numerous cultivars presenting additional bark colours of green, yellow, coral and purple-black. Indeed it is this trait that makes dogwood so desirable in Northern climes – our winters are long and it provides a bright spot in a dreary landscape. The branches are often used in seasonal container arrangements as well, since they hold their colour well when cut.

Cornus sericea (red osier dogwood) lines the banks of the Bow River, its massive root system preventing erosion, and its colourful stems brightening the winter landscape. Photo: Pat Gaviller

The pliable branches are also useful for various crafts – basketweaving for example. Dream catchers too, were traditionally made of red osier dogwood, which some considered to be sacred.

Colourful bark makes dogwood branches useful in other landscape applications – the detail in the viewing window on the left is made from dogwood which I harvested from one of my very mature Cornus sericea ‘Flavirimea’. I then had my friend and colleague, Greg Booth of Sawback Developments, fashion this Japanese-style gate for a client. Photos: Sue Gaviller

Since it is the younger branches that are the most colourful, keeping old branches pruned out will ensure good bark colour. Very old, untidy specimens can be ‘rejuvenated’ by pruning them to the ground. Your efforts will be rewarded with lush new growth the following year.

Spring Flowers and Summer Berries

All of the C. Sericea and C. Alba cultivars have delicate white flowers in spring. Some years they flower abundantly, other years more sporadically, and while the blooms can’t compete visually with those of Malus or Syringa, they are nonetheless suitably pretty. In late summer these pretty white flowers become pretty white berries, which are especially attractive against the changing foliage colour.

Dogwood berries provide food for many species of birds – too numerous to list here. Suffice it to say that if you want to attract birds to your yard, include a native dogwood or two in your plan.

Dogwood flowers, though not particularly showy, still have ornamental value in the landscape. Left: Cornus sericea. Photo: Pat Gaviller. Right: Cornus alba ‘Aurea’. Photo credit: Wikipedia

Cornus sericea: small white flower clusters become cream-coloured berries – stunning against the red fall foliage. Photos: Pat Gaviller

Foliage Colour All Season Long

Cornus sericea and Cornus alba contribute both texture and colour to the garden. Texturally they are medium-coarse – these coarser textures are desirable for providing moments of emphasis and contrast in the landscape. As for colour, there is increasing variety in available foliage colours – bright gold, bronze-green, variegated green and gold, variegated green and white, and of course basic green. With all these colours to choose from, the lowly dogwood shrub can make a real splash in your garden.

Cornus alba ‘Aurea’ has intense bright golden foliage – a real standout. Here it contrasts beautifully with the dark green of Syringa vulgaris and the rich wine-coloured Physocarpus opulifolius ‘Summer Wine’. With colour like this who needs flowers? Photo: Sue Gaviller

Cornus alba ‘Strawberry Daiquiri’ (left) has very white leaf margins and strawberry coloured bark, while Cornus alba ‘Cream Cracker’ has butter cream variegation and dark purple-red bark. Such yummy names aren’t they? Photos: Sue Gaviller

Cornus sericea ‘Silver & Gold’ has green and cream variegated leaves and bright yellow bark – an attractive addition to the landscape any time of year. Photo: Sue Gaviller

Dogwoods also have brilliant fall foliage colour – the red-barked cultivars turn varying shades of red, the yellow-barked cultivars turn golden and the variegated cultivars turn shades of peach, pink or orange. These Cornus shrub species really do have something to offer in all four seasons – few plants have such versatility.

The bright red fall foliage of this small compact dogwood (which I suspect is Cornus sericea ‘Farrow’) looks stunning against the backdrop of a richly stained fence and the limestone boulder in the foreground. Photo: Sue Gaviller

Cornus alba ‘Cream Cracker’ in late summer, just beginning to show its fall colours. Photo: Sue Gaviller

Size Matters

C. sericea and C. alba species are quite large – 2 to 3 meters height and spread. This is great if you have lots of room, but if not, there are many cultivars bred specifically for the smaller yard. Cornus sericea ‘Farrow’ (Arctic Fire dogwood) is a compact bushy cultivar with lush green leaves and intense red stems, reaching about 1 meter tall and wide. Cornus sericea ‘Kelseyi’ is a cute little dwarf variety growing only about ½ metre. For variegated cultivars, the very pretty Cornus alba ‘Cream Cracker’ is a great choice for small yards with a height and spread of about 1 metre.

This client’s Northwest Calgary yard was one of the first designs in which I used Cornus alba ‘Cream Cracker’. I’ve been very happy with its performance – very little winterkill, bushy compact growth habit and beautiful warm variegated foliage has made it a great choice. Photo: Pat Gaviller

Dogwoods aren’t picky about where you put them – I have 12 or 13 of them in my yard, numerous cultivars of both species, placed in every conceivable growing condition – shade, semi-shade, full sun, moist, dry, sheltered, exposed and several combinations thereof. I can’t say any particular specimen is doing markedly better than others – the one in full sun with supplemental water from the downspout has perhaps grown the fastest, but on the whole they’re all pretty happy.

So you see there’s a dogwood for everyone, for every site, and for every season. Indeed they are a gardener’s best friend.

Thank y’all for reading,

Sue

© Sue Gaviller and Not Another Gardening Blog 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Sue Gaviller and Not Another Gardening Blog with appropriate and specific direction to the original content.

Native Plants: Red-stem dogwood a good choice for yards (redding.com)

Curtain Call – Farewell to Sweet Syringa

Jul12

So y’all know how much I love lilacs. Well I’m sad to say they are nearing the end of their bloom period, so I wanted to give you a look at the closing act before the curtain is drawn on another season. I know, enough with the lilacs already – I assure you though, today will be my last post on this loveliest of blossoms (at least for this year) and I promise to keep it short.

Syringa reticulata – Japanese Tree Lilac

These gorgeous, very late bloomers have been flowering for a week or so in our part of the world. They weren’t in bloom for my June lilac post but they are so utterly stunning this year, that I had to bring them to your attention. The Japanese tree lilac is the last of the lilacs to bloom and has some unique characteristics not shared by others in the genus:

They are a true tree, as opposed to a large shrub that gardeners prune into a tree ‘shape’ and labour to maintain.
The bark is a dark chocolate-brown with very noticeable lenticels.
The flowers are borne in panicles like all other Syringa species but have much finer texture, their feathery appearance in striking contrast to the large shiny leaves.
The scent isn’t recognizably lilac; it’s hard to describe, but if you get a whiff of something sweet and a bit spicy, like vanilla with a hint of anise, look around – there’s likely a tree lilac in the vicinity. Their bright white blooms make them easy to spot.
There is even a variegated cultivar which blooms later still (mine is just coming into bloom now) – ‘Golden Eclipse’ has large green and gold leaves.

Intense white blooms cover this compact tree. Photo: Pat Gaviller

Soft fluffy blooms, dark green foliage and richly textured, chocolate-coloured bark make the Japanese tree lilac a must-have in the urban landscape. Photo: Pat Gaviller

Full feathery plumes light up a sapphire sky. Photo: Sue Gaviller

Syringa reticulata, with its honey-sweet scent is a favourite of bees and butterflies. Photo: Cathy Gaviller

Syringa reticulata ‘Golden Eclipse’ is a very hardy variegated cultivar – leaves on new growth emerge dark green splashed with lime and older growth has bright green and gold variegation. Photo: Sue Gaviller

Sum it all up and you have a great specimen tree – a tree with four season interest. The Japanese tree lilac has real design value and in my opinion is greatly underutilized in the landscape. It’s perfect for use as a dominant feature – for its elegant form (particularly if multistem), its colour (especially Golden Eclipse) and its coarse texture.

Syringa reticulata is a worthy closing act to a truly fine show that began 6 weeks ago – the lilac show.

So say goodbye to sweet Syringa – may their scent be with you.

Sue

Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Sue Gaviller and Not Another Gardening Blog with appropriate and specific direction to the original content.

Form, Colour and Texture in the Winter Garden

Mar14

I had hoped to follow up with this second post on “Winter in the Garden” before now, but photo shoots take time, especially for a beginner photographer like me. However, this is Calgary and winter will be sure to hang around for a bit longer, so the topic is still timely.

In my last post I discussed Focal Points and their value in the winter garden. You’ll recall from that discussion, that a focal point refers to a ‘hard’ or non-living feature that draws the eye. We can also employ ‘soft’ or living elements in the garden to create winter interest – plant material that contributes form, colour and texture.

Form

Plants with strong architectural form offer a unique kind of winter interest – naked of foliage from fall through spring, their distinctive silhouette draws the eye in much the same way as a focal point, hence many of the same guidelines would apply: don’t overuse, make sure they are planted perfectly upright (they will sometimes lean over time so need to be straightened periodically) and stage them for maximum visual impact.

So what constitutes ‘strong architectural form’? There are a number of plant shapes that fit the bill. I find that ‘weeping standards’ are among the most dominant of plant forms – small weeping ‘trees’ which are developed by grafting a pendulous or prostrate form onto a standard, e.g. Malus ‘Rosy Glo’, Betula pendula ‘Youngii’. These little beauties bring real elegance to a composition. Not surprising then that gardeners often make the erroneous assumption that because one looks awesome, two will look even better. More is better? This may be a great philosophy – when it comes to lobster, or cheesecake, but not here. I made this mistake in my own front yard a few years ago. On one side of the yard a Royal Beauty weeping crab took centre stage and I wanted something interesting to balance it on the other side. Off I went to the nearest greenhouse to look for the perfect garden addition. A beautiful Young’s weeping birch caught my eye. Oh yes, I thought, that will be perfect for that spot. I should really know better – in fact even as I stood in line I was having an internal dialogue: “Sue, you already have a weeping standard in the front yard – another one would be overkill”… “But, but it’s such a perfect specimen and the bark will look lovely against the cedar fence in the winter”. Well, the gardener won out over the designer – I bought it and had it planted within an hour. I guess it looked okay, but it didn’t take my breath away. The real effect was that each of the two similarly strong features diminished the impact of the other, even though they were 40 feet apart.

As I scrutinized this over the next few weeks, I eventually decided that it wasn’t ideal but it would have to do … for awhile anyway. It has of course, now been replaced – like I said I should know better. Weeping standards are definitely best used as single specimens. But enough about my garden challenges.

This attractive little Caragana arborescens ‘Walker’s Weeping’ has been nicely staged by underplanting with a Juniperus sabina cultivar and framing with 2 Juniperus scopulorum specimens – likely Wichita Blue. Photo: Sue Gaviller

Additional plant forms that are distinctive and provide winter appeal would be:

other top grafted standards, e.g. top-graft Syringa meyeri
columnar trees, e.g. Populus tremula ‘Erecta’
vase shape trees e.g. Caragana arborescens ‘Sutherland’, Malus ‘Pink Spires’
tall upright grasses e.g. Calmagrostis acutiflora ‘Karl Foerster’ or ‘Avalanche’
evergreen topiary e.g. Juniperus chinensis ‘Mint Julep’(pom-pom)

These can be used as single specimens, and with the exception of certain topiary forms (e.g. pom-poms), they can also be grouped, used to frame entrances/views or planted sequentially to direct visual movement and reinforce design lines. And while more than one can be used in a composition, they too if overused, will create visual unrest.

This ‘pom-pom’ topiary pine is appropriately used as a single specimen. Here, it needs very little staging as the detail on the house is an effective backdrop. The upright blue juniper supports visually too, although appears to have once been a topiary specimen itself – it would be best if allowed to revert to natural form so as not to compete with the pine. Photo: Pat Gaviller

This grouping of spire-like Populus tremula ‘Erecta’ creates a stately feel in an otherwise informal landscape. Photo: Sue Gaviller

The upright form of these Calamagrostis acutiflora ‘Avalanche’, effectively directs visual movement along the pathway in one of my client’s front yards. Photo: Sue Gaviller

Top-grafted standards like this Syringa meyeri, provide strong form while allowing a view beneath it to what lies beyond.

You can get away with using numerous strong forms if they aren’t all the same shape. For example when I removed the Young’s weeping birch, I replaced it with a Pink Spires Crabapple – a lovely vase shape tree. In front of this I placed a bird bath – these two together created a co-dominant ‘focal vignette’, completely different in appearance from the weeping crab. Hence the effect is that they support rather than compete with each other.

For the average gardener it can be hard to predict how certain plant forms will work together – just keep in mind that the more striking or unusual its form, the more likely it is that it will need to stand alone.

I will be discussing plant form in more detail in a later post, but in the meantime the best advice I can give you is to practice some restraint. (Really? Is that even possible for a gardener?)

Colour

There is of course a limited palette available to us at this time of year – let’s see, gray, brown, grayish brown, brownish gray, sometimes white, some green, a bit of blue. Anything else? Well yes actually – take a look:

Many trees have colourful bark, in varying hues of green, yellow, orange, red and purple. These colours may be less saturated than the colours of summer, but because they are exhibited by an entire tree or shrub, the effect can be quite dramatic. Photos: Sue Gaviller

The beautiful bronze bark of this Prunus mackii picks up the warm hues of the wood and stone on the house. These same colours are seen again in the boulder in the foreground. Photo: Pat Gaviller

This landscape was also featured in my last post. I’ve included another photo, (minus the lopsided light fixture), because it’s an excellent example of how colourful a winterscape can be. Photo: Sue Gaviller

Berries too can provide winter appeal. The visual impact will be determined by the amount of fruit and it’s size – this may vary from year to year. As well, berries with little water content, like the above examples, will retain colour better through the winter than juicier fruits.

The abundance of Hippophae rhamnoides berries caught my eye when driving by this landscape – a good illustration of the use of form, colour and texture to provide winter interest. Photo: Sue Gaviller

While all conifers provide winter interest, it is the rich green of several Pinus mugo that enlivens this scene. Imagine how drab it would appear without them. Photo: Pat Gaviller

Evergreen Colour

I aim for at least 1/3 of the plant material in a composition to be evergreen – and I mean evergreen, not everblue. Not that I don’t love blue spruces and blue junipers – I do, and they should be used, but not to the exclusion of green. Blue-grey foliage has less pigment than green foliage, hence can contribute to the washed-out look of a winter landscape, especially in the absence of snow. If you’ve ever been to one of my Colour Theory lectures, you know my thoughts on green – it’s the most important colour in your landscape, the colour which allows other colours to have significance.

Green is the colour of life (plant life that is). It can tame the most unruly of hues, add visual depth and infuse richness into your landscape year round. So for every blue conifer you use, plant a few green ones. You’ll see how much more alive your garden will look in the dead of winter.

Texture

Textural contrast is another important consideration when planning your garden. Texture can be fine or coarse – during the growing season, fine texture generally refers to small leaves or flowers that are grouped closely together, and coarse texture would be large leaves or flowers spaced further apart. During the winter months though, we need to look at texture differently. Since most herbaceous perennials have little or no presence in the winter, and most deciduous trees and shrubs lose their foliage entirely, then it is the texture of their bark and branches we see. Spiraea and Potentilla, for example are fine textured – their branches are small, twiggy and tightly spaced. Syringa and Fraxinus (especially males) have much coarser texture – their branches are beefier, and more widely spaced. At any time of year too much tiny, tightly packed foliage, flowers or branches will end up looking busy, so punctuating with some coarse texture will create both emphasis and contrast.

Texture can also refer to the surface of something – is it rough or smooth, shiny or matte. In the winter this will refer mostly to the bark of trees and shrubs.

Compare the very different texture of the above three trees – the oddly flaking bark of Pinus sylvestris (left), the twisted striated bark of Crataegus mordenensis ‘Toba’(centre), and the shiny peeling bark of Prunus mackii (right). Photos: Sue Gaviller

Evergreen Texture

All evergreen foliage is considered fine textured – narrow needles spaced closely, and yet they appear texturally quite different. Some appear weightier than others – they may be denser or the needles longer, or stiffer. Use of contrast in this regard will produce superior results to utilizing a single type of evergreen. Yet another example of me not practicing what I preach – I have too many junipers in my backyard, with few other evergreen foliage types (that and my Rosy Glo has developed quite a lean).

These conifers are all fine textured, but they differ in perceived weight. The lacy foliage of Juniperus chinensis ‘Mint Julep’ (right), appears lighter and airier than the stiff needled Pinus mugo (left) and Picea pungens ‘Globosa’ (middle). Photo: Sue Gaviller

The beauty of winter is that it offers us a glimpse of colour and texture combinations that would be obscured in other seasons by branches clothed in foliage. Photo: Sue Gaviller

I invite you to open your eyes to the beauty that is winter – at least for a few more weeks.

Spring is coming.

Til then,

Sue