September, the month where there's a change. Kids are just back to school, lawns are again a lush green, as temperatures have begun to cool giving a fresh crispness to the air. There is a new energy, there is a significant difference.
Drive through the neighborhood and you will take notice of difference that is beginning. The trees and shrubs around us are transitioning to new colors. The deep green color tones of our deciduous trees are softening; mellowing to yellows, ambers, oranges and rich reds.
The deep green foliage color of trees and shrubs is maintained spring through summer with the presence of chlorophyll. Acting much like a layer of sunscreen chlorophyll keeps the leaves of many plants safe in their natural color. In autumn when the xylem and phloem component of a tree's nutrient liquid force slows, the chlorophyll production is reduced and eventually shuts down. When this process occurs the rich color tones from yellow to orange and red begin to show. These colors have always been within the plant leaf, but it has always been masked by the chlorophyll – the green colorant. In the case of burgundy or red leafed trees and shrubs, it is the green chlorophyll tones that are masked by the more dominant pigment. Studies show pigments high in carotenoids (which also give carrots their bright orange color) show in shades of yellows to oranges while pigments high in anthocyanins reveal strong red to purple colors.
Varieties of trees, shrubs, vines and some perennials possess this color changing display. This characteristic is favorable to the landscape. Just as a designer chooses spring and summer blossoming trees for effect, the designer will implement the use of varieties with leaf color change to create an atmosphere, an effect or image. Landscapes large or small can make use of the alternative color changes of plants. Mass plantings of such plants may be implemented, or it may be the focus of the designer to have specimen varieties used as a stand - alone statement.
Deciduous trees such as the ash, maples and linden varieties will turn golden to slight amber tones. Amur maples, maples and Saskatoons in both tree and shrub form are desired for their deep orange sometimes reddish colors. When seeking upright evergreen specimens such as Larch ( Larix sibirica ), these will color nicely in the fall with yellow to soft amber exuding from their fine needles before they defoliate for the winter. Low spreading junipers such as Bar Harbour junipers whose blue green sprigs turn to a bronze-purple hue in cold temperatures add color to a landscape.
Favorable shrubs with color accents would be the dogwoods; Siberian or red osier varieties which turn to deep burgundy red in fall. Their striking red stemming is an additional characteristic of these shrubs. Once the leaves have drop, the red stems are a nice contrast to the clear white snow over the winter months. Look for Cotoneaster and alpine current shrubs as hedging selections; beginning their season with a bright green color changing to deep plum red in the fall. Top picks would also include Euonymus which turns a deep red burgundy and Sumac Tiger Eyes with its bright yellow textured foliage. Stunning in their colorful fall glory.
Climbing plants such as Engelman ivy and Virginia Creeper serve to provide vertical height to the garden or provide a living density to chain-link fencing; eventually providing privacy with mature growth. These plants too, transform in color once the temperatures change.
Perennial selections are not exempt from the "color change". Sedum plants also have similar characteristics in foliage color; taking on a different hue with cooler temperatures. Perennial grasses such as Miscanthus Flame grass and Calamagrostis ‘Karl Foerster’ have been used favorably in both residential and commercial landscapes for both their color accenting as well as their strength as structural plants in the landscape. Heucheras, known also as Coral bells set a tone in the garden as their rich amber and deep burgundy tones stand out in their richness.
As you look to continue planting into the warm autumn ground of fall, you may venture into a garden centre checking which trees, shrubs, or perennials may warm your landscape with autumn color. There are more than those mentioned above. Visit to see which color accent best suites your location.
St. Mary’s Nursery & Garden Centre’s greenhouses carry numerous perennials, trees and shrubs. St. Mary’s Nursery has the expertise to help you in your selections for all your planting requirements.