Shade and ornamental trees can play a key role in our increasing focus on sustainability . They help remove pollution particles from the air, convert carbon dioxide into the oxygen we breathe, absorb and redistribute storm water and aid in reducing both cooling and heating costs. Besides that, they add value to our lives in many other ways. It is well documented that in urban areas the development of urban forests actually saves communities millions of dollars each year.
We may be unable to influence the planting of urban trees, but we can locate them strategically in our own gardens. The old vision of huge trees shading and overpowering our gardens and the inevitable high maintenance cost it takes just to keep them trimmed is a thing of the past. New compact and narrower tree forms fit nicely into smaller gardens with impressive results. As we enter one of the more colorful seasons of the year, it becomes even more evident that many trees also add remarkable beauty to our homes and gardens.
I have always been a huge fan of eastern red maples that light up Ontario and Quebec forests each fall. These can also add a great deal of value to western gardens.
And now that they include more compact forms, they’ve become true home garden jewels. The variety with the narrowest form is Acer rubrum ‘Armstrong,’ growing only 14m (45′) tall and 4.Sm (15′) wide. Its fall colouring is yellow and orange-red. Another very narrow cultivar is A.r. ‘Bowhall’ with fall colours of yellow, orange and reddish-orange. Both are hardy to Zone 4 and make great gar¬den focal points. With a little pruning they can become even narrower and more compact.
If you need a little more width to screen out close neighbours, both A.r. ‘Autumn Spire’ (Zone 3) and ‘Scarlet Sentinel’ (Zone 4) are spectacular. ‘Autumn Spire’ has brilliant red leaves while ‘Scarlet Sentinel’ is more of a yellow-orange to orange-red. grow to about 12m (40′) tall and about 6m (20′) wide. Compare these to more traditional maples that grow up to a width of 12m (40′), twice the size, and you will appreciate what they have to offer.
New compact and narrower tree forms fit nicely into smaller gardens with impressive results
I really enjoy dogwoods, and unfortunately, I feel many of us are missing their year round beauty in our gardens. Four of my favourites are the centennial tree for Vancouver, Cornus ‘Eddie’s White Wonder’ (Zone 6), the new Cornus kousa Samaritan® (Zone 5) and C.k. ‘Venus’ (Zone Sb) and the new introduction for 2009, C. nlternifolin ‘Wstackman’ (Golden Shadows”, Zone 3). ‘Eddie’s White Wonder’ is a large, clean flowering dogwood with slightly pendulous branches. It grows up to 8m (25′) and has stunning red fall colour. Cornus k. ‘Samzam’ (Samaritan®), a new 2008 introduction with very clean rich cream and white variegations, turns the most amazing pinkish-red in the fall. It will grow up to 6m (20′) and has, as a young tree, quite a nice narrow form. Cornus k. ‘Venus’ is one of the largest flowering dogwoods with creamy white blooms up to 15cm (6″) across. It grows to 6m (20′) and sports fall colours from red to deep purple¬red. Camus Golden Shadows® is about to be introduced next year and it is truly sensational. Growing only Sm (15′) tall, and in typical alternifolia layering fashion, it has magnificent variegated gold and green foliage that turns a gorgeous reddish-purple in autumn. It is a must-have.
Many stunning Japanese maples are right at home in small gardens. And with a little cosmetic pruning, they can be kept quite compact. The first-ever columnar red maple is Acer palmatum ‘Twombly’s Red Sentinel’ (Zone 5). This new variety grows 4m (13′) with a spread of approximately 2m (6.5′). It holds its red colour well during hot summers and in fall it becomes a brilliant showpiece. One of the hardiest of all Japanese maples is the paper bark maple or Acer griseum (Zone 4). It grows to 8m (26′) and is one of the most interesting maples in winter with its unique peeling red bark. Although it is the last maple to leaf out in spring, its olive-green leaves give way to the most striking pure red. The noted, most brilliant of all fall coloured maple is Acer palmatum ‘Osakazuki’ (Zone 6). This large-leaved variety changes its leaf colour constantly from spring right through fall. Its green leaves change to yellow then to green-gold and later to the most intense fluorescent crimson that lasts for weeks. Growing to about 4m (13′), it is a garden must-have.
Introduced in Ireland back in 1920, Acer palmatum ‘Sango-kaku’ is yet another winter showpiece with its rich looking deep coral stems. During spring and summer its leaves are a vibrant yellow-green intensifying to deep yellow in fall. Its rich coral stems and yellow foliage are a match made in heaven. It will grow to 5.5m (18′) and is absolutely delightful.
Sweet Gum Tree
The gorgeous liriodendron or sweet gum tree has traditionally been far too big for small space gardens, but a new introduction, Liriodendrori styraciflua ‘Emerald Sentinel,’ has changed all that. Growing slowly to only 10m (33′) with an ultimate width of 3m (10′), it is a clean pest-free tree with fabulous yellow-orange foliage turning to a stunning orange fall colour.
Many of us have soft spots for oaks, but most varieties are huge and unsuitable for smaller spaces. Crimson Spire” however, grows only 12m (39′) tall and 3m (10′) wide. It has a tight habit, clean foliage and lush rich reddish fall colour. Hardy to Zone 5, it makes a fine new addition for our gardens.
Probably the most under-utilized tree in gardens today is the sourwood or Oxydendrum arboreum. Hardy to Zone 5 and growing only 6m (20′) tall and 4m (13′) wide, it is a slow growing tree with shiny light green foliage that The fall colour of a Crimson Spire” lea, has a copper tinge and turns the most fiery orange-scarlet you can imagine. Long creamy white bell-shaped flowers appear in August each year, adding a new dimension to summer colour. It is one of my favourites.
Thank you Persia for the beautiful Parrotia persica that makes our gardens shine twice a year. Showy red stamens appear each March followed by shiny hazelnut-like leaves that turn brilliant shades of red, yellow and orange each fall.
This is a very unusual tree that is hardy to Zone 5 and grows slowly to 10m (33′) in height and 6m (20′) wide at maturity. It is worth finding a spot in your garden for this gem. These trees are a few of my favourites, not just for fall colour, but for year-round interest.