One thing I especially love about North Carolina, as a native of Canada, is that it has mild winters and yet we also experience four distinct seasons. I can still enjoy the seasonal changes that I have grown accustomed to as a child. Of particular joy for me is the fleeting period in the fall when the green foliage of the deciduous forest dramatically changes to bright warm colors. Is it just me or are the fall colors more vibrant in the Triangle this year? The autumn display reminded me of my youthful memories of the orange and brilliant colors of southern Ontario especially against our brilliant blue Carolina sky.
Rich Native Color: Yellow, Gold, Orange, Red, Burgundy and Copper
As I transition to a native garden and strive for more year-round interest in my landscape, I have been paying closer attention to the fall color of the plants I purchase. Formerly, fall color was a neglected dimension in my garden landscape as I focused on planting evergreen screens and summer flowers. I wanted to try to add more orange and reds reminiscent of the sugar maples of my youth so I have planted Fothergilla ‘Mount Airy’ and transplanted some ‘volunteer’ Red Maples (Acer rubrum) and Flowering Dogwoods (Cornus florida). Fortunately, North Carolina has an abundant variety of tree, shrub and herbaceous plant species the provide spectacular color in the autumn.
I also transplanted some Winged sumac (Rhus copallinium) next to my sitting bench from the woodland natural area in my yard.
With large trees of American Beech (Fagus grandifolia), Hickory (Carya cordiformis), White Oak (Quercus alba), Eastern Redbud (Cercis canadensis), Sweet Gum (Liquidamba styraciflua) and Red Oak (Quercus rubra), I already had plenty of gold, yellow and golden brown with some dark red colors to view in my yard.
American Beech (Photo taken on November 11, 2018) , Eastern Redbud leaves with Muhly Grass (Muhlenbergia capillaris ‘White Cloud’; fall blooms not leaf color, photo taken November 10, 2021), Hickory and White Oak canopy (photo taken on November 15, 2021) and Red Oak (photo taken on December 4, 2020). Photos by Wendy Diaz
Collection of fall leaves from my yard. Sourwood, Sweet gum, Beech, Red Oak, Dogwood, Red Maple and Blueberry, Photo taken November 24, 2020. Black Gum (Nyssa sylvatica) seedling; photo taken November 9, 2021
A Black Gum tree (Nyssa sylvatica) tree in my backyard died during a dry period in 2019 but recently I saw a small seedling nearby and I hope it will grow up tall so I can see its brilliant orange oval leaves from my office window in a few years. I transplanted Red Maple seedlings in front of a grove of Hickory trees to obtain some layering and depth in my narrow back yard during autumn. In 2020, I purchased and planted a Sourwood (Oxydendrum arboreum) seedling for more color in our small front yard. The occasional evergreen Red Cedar (Juniperus virginiana) and Magnolia (Magnolia grandiflora) trees provide a bright green contrast to fall colors of the deciduous trees and seem to make the fall colors stand out in the woodland landscape.
There are a variety of native trees shrubs that grow well in the Piedmont that are beautiful in the fall like Blueberry (Vaccinium corymbosum), Virginia Sweetspire (Itea virginica) and my favorite Oakleaf Hydrangea (Hydrangea quercifolia).
Blueberry bush under Loblolly Pine, photo taken December 2, 2020. Closeup of blueberry leaves turning from green to yellow and orangey red, photo taken November 28, 2020. Brilliant orange, yellow and unique burgundy colors of Oakleaf Hydrangea, photo taken November 24, 2020. Range of leaf color on Oakleaf Hydrangea bush at one time, photo taken November 27, 2020. Oakleaf Hydrangea in foreground and American Beech in background of photo taken November 24, 2021. Photos by Wendy Diaz
Several years ago, I pulled off some invasive vines from a thicket of Arrowwood (Viburnum dentatum) and now I am treated in the morning light with a view of the coppery shimmer of the arrowwood’s leaves.
Arrowwood thicket in the morning light, photo taken November 21, 2021. Closeup of copper brown color of Arrowwood leaves, photo taken December 2, 2020 and morning light shining through copper colored leaves of arrowood, photo taken November 18, 2021.
Also, outstanding fall color can be obtained in your home landscape by planting such native herbaceous perennials as Amsonia (Amsonia hubrichtii), New York Ironweed (Vernonia noveboracensis; actually seed heads have the color not foliage), Virginia Creeper (Parthenocissus quinquefolia) and even Scarlet Rose Mallow (Hibiscus coccineus) puts on a vibrant display.
Why causes leaves change color?
In the autumn when the temperature cools and the days are shorter it triggers the leaves to change color. Through a process called senescence the plant goes dormant at the end of the growing season and the leaves begin to die. Leaves contain pigments that absorb light and certain pigments absorb different wavelengths of light. Most of the pigments in the deciduous leaf are chlorophyll a and chlorophyll b and absorb light in the violet, blue and red wavelengths of light and reflect back green wavelengths which we see in the spring and fall. Leaves also contain carotenoids (including carotene and xanthophyll), another class of pigments. The underlying orange and yellow carotenoids reveal themselves after the chlorophyll pigment breaks down first in the leaf in response to cooler temperatures. Red colors are produced by anthocyaninsand trees that have red fall leaves contain anthocyanin pigments. Yellow leaves contain mostly xanthophyll pigments, orange leaves contain carotene pigments but only are visible after the chlorophyll fades. Like chlorophyll these pigments are produced in the spring but anthocyanins are produced at the beginning of the fall. Cooler temperatures make the sap viscosity increase and tougher for water to be transported throughout the tree and this helps sugars build up in the leaves which triggers the production of more anthocyanins. Color depends on environmental factors so color brilliance can vary a lot. Factors like the number of clear cold nights, sunny days and rainfall and the timing of the first freeze all affect fall color intensity so even if you expect to have a brilliant orange or red maple every year you may not, if the growing season environmental conditions were not ideal and included a drought or early freeze. Generally, the most vivid colors occur when there are cool nights and sunny days starting in September. This explains the especially vibrant fall display this year in the Triangle because we have had a dry fall with our fair share of cool nights and clear blue skies.
Remember to keep (rake them off your grass and put them under a tree) or leave your leaves where they fall as they provide nutrients for your trees and provide shelter for many insects that birds need for food. Leave your leaf groundcover and conserve this valuable natural resource and if you live in Durham don’t forget to make the pledge to keep your leaves. I hope you had a chance to enjoy our bright fall color display in the Piedmont this year while working in your own yard or walking in the deciduous forest nearby.
By guest contributor Barbara Driscoll, President, New Hope Audubon Society
It’s that time of year again when the leaves are turning red, orange and gold, and starting to drop to the ground.
These leaves provide nutrients for the trees they came from and also shelter for many insects. It may surprise you to know that most of our butterflies and moths overwinter in the leaves in the form of eggs, caterpillars or chrysalis, and even some adult butterflies such as the Questionmark, Comma or Mourning Cloak spend the winter sheltered in the leaves or bushes. Luna moths and swallowtail butterflies disguise their cocoons and chrysalis as dried leaves which wait in the litter until spring to emerge.
Lots of insects use the leaf litter as a place to live or over winter, and our birds know this is a good place to look for food. Hermit thrush, white-throated sparrows and other birds can be seen kicking and picking through the leaves for bugs to eat. So many insects live in the leaves: spiders, snails, worms, beetles, millipedes and more – and they support chipmunks, turtles and amphibians which rely on insects for food.
So, sit back, relax, enjoy the leaves and don’t work so hard at tidying up the yard because those leaves are providing a lot of good to wildlife. Research has shown that a thin layer of leaves does not harm your lawn, but if you are concerned about it then blow or rake the leaves to another part of your yard. After all it is free mulch and provides much needed nutrients to your trees and plants. It’s best not to shred the leaves as that will destroy many of the insects, and bagging or blowing the leaves curbside is like giving away free mulch. An even better approach is to reduce the amount of green lawn and replace it with native plants. Take back that time you spent removing the leaves and start enjoying them and the benefit it provides to wildlife and your yard!
If you would like additional information, much of the information for this blog came from a blog by the Xerces Society for Invertebrate Conservation, or please refer to a previous post, “Littering with Leaves” by Jim George in October 2017. For more information on making your yard friendlier to birds and other wildlife visit the sections of our webpage about creating a “Bird Friendly Habitat.”
Well, what do you know?! It’s November…already. Transition month in the piedmont of NC—Fall to Winter although winter of late has been more like an extended November. Way better than an extended January. There’s not a lot left to do gardening wise. Mostly just putting things to bed (pun intended). The Accidental Cottage Garden looks like what one would expect a perennial garden to look like in November…not good. The hardy ageratum (Eupitorium coelstinum) is pleased with the recent rains having been not so much pleased with the preceding long dry period. The chrysanthemum (C. noclueuia) is about 50/50 yellow and brown. Other than the uberprolific Knock Out rose, there are a few gallardia (Gallardia pulchella) still in bloom and a clump of Chinese chives (Allium tuberosum) which the bees just love. The bed beside the driveway has been tilled in preparation for a complete makeover. Next year should be interesting. Stay tuned.
Now let’s go outside and play in the dirt before it gets too cold.
Keep all lawns mostly leaf free, taking advantage of the leaves by moving them to garden beds. Cool season grasses (fescue, bluegrass, perennial rye) are still growing. Keep them mowed between 3” and 4”. Continue the war on fire ants (Solenopsis invicta Buren—red, S. richteri Forle—black). They can be treated with boric acid powder or diatomaceous earth if you have an aversion to lethal chemicals.
November is a slow time for you frequent fertilizers. However, you can check the results of your as yet (through November) FREE soil test and add lime to your soil per the recommendation. A good way to incorporate the lime is to core aerate the soil prior to applying the lime. This will get the lime down into the root zone where it will be of the most benefit.
If you have a wood burning fireplace you can dispose of the cool ashes around trees and shrubs. Be sure to avoid ericaceous (acid loving) plants (azaleas, camellias, gardenias).
For those of you who might have missed it earlier, FALL IS FOR PLANTING! Especially now that there is moisture in the soil it is time to run out and transplant the things that need a different living arrangement and/or add new things to the garden. Be adventurous and plant a native species or six. They are low maintenance, relatively pest free and usually deer and bunny resistant. Ain’t nothin’ deer proof if the deer are hungry enough.
Plant one-year-old asparagus crowns this month.
Sow a cover crop in the currently unused parts of the veggie garden. Annual rye, wheat, barley and alfalfa are good choices. They will mitigate erosion, keep weeds to a minimum and add organic matter when tilled into the soil in the Spring. Win, win, win!
Nope, nada, nichts, rien. The equipment should already be cleaned and put away.
OTHER STUFF TO KEEP YOU OUTSIDE LONG ENOUGH TO MAKE A HOT BEVERAGE SOUND REALLY GOOD
Well, there you have it. May each of you have a wonder filled, nearly normal Thanksgiving. Be sure to prepare enough to share with someone who otherwise might not have any. Remember, COVID is still out there, so be safe and let us not be foolish.
RESOURCES AND FURTHER READING
Looking for a way to help your soil and local critters while cutting down work? Leave the leaves this year! As leaves break down they provide carbon and nutrients back to the soil, and leaf litter is critical habitat for any number of invertebrates and other small friends. Learn more, and take the pledge at https://keepdurhambeautiful.org/leaveyourleaves. As a bonus, by taking the pledge you can get a free yarn sign to help spread the word!
If you’ve come to the Extension Office at 721 Foster St recently, you will have noticed the gabion planters on either side of the front door entry. These new planters were installed in April of this year, and planted with grasses, vines, and annual and perennial flowers shortly thereafter.
Gabion (mid-16th century) comes from the Italian gabbione, from gabbia ‘cage’, which came from the Latin cavea. Basically, it is a cage filled with rock, concrete, or earth, historically used in fortifications, retaining walls, and in the prevention of erosion in river banks. Gabions of this type can be seen at the Museum of Life and Science in Durham, where they are used to form supports for overhead train tracks, and as edging around seating areas.
They have also been seen as beautiful erosion control walls in Durham.
I first saw gabions used as planters upon a visit to the Reford Gardens/Jardins de Métis, in Métis sur Mer, Quebec, in October, 2019. One was a ‘walk-in’ gabion with a hanging tray of succulent plants inside; part of an art installation in the Festival International des Jardins.
The second was in a part of the garden where horticulture students are encouraged to build on the previous year’s students’ installations, and consisted of a gabion filled with old books, including the occasional textbook (to my amusement several Chemistry textbooks, and perhaps presciently, an upside-down Virology textbook) along with other books and magazines.
When it came time to think about planters for the Demonstration Garden, our first thoughts had been the silver troughs, which had become ubiquitous throughout Durham. Remembering the gabion planters, I suggested we pursue this as an alternative. This led to a field trip with Peter Gilmer to the aforementioned museum where Manager of Horticulture Bobbi Jo Holmes showed us their gabions. She was also able to point us to a material supplier for the metalworks, and Peter was able to donate the rocks for the project.
Peter carefully researched our options and chose Stone Decorative www.stonedecorative.com as our vendor after much discussion on size, shape, and size of the mesh. We chose industrial (vs landscape) gabion panels because of higher gauge, thus stronger, wire, which was Galfan-coated galvanized steel and came in 36” x 36” x 18” panels. Also included were spiral binders and tie wires which stabilized the walls to each other. The panels (6 in all—top, bottom, and 4 sides) were shipped in a flat box, and assembly proved very easy with the spiral binders.
We had decided the gabions would provide more visual interest if they were placed at an angle to the sidewalk and building, rather than running parallel to the sidewalk. Peter cleared and leveled the soil, then put down several inches of pea gravel as a base. The gabion panels were assembled using the spiral binders, put in place, and rocks installed. By utilizing the leftover top panels, and purchasing two more panels, Peter constructed an inner box for each gabion.
Once the inner box was installed, rocks were carefully placed between the two boxes, and the inner box lined with heavy landscape fabric to prevent soil washout. In early June, soil was put in and the gabions planted by Joan Barber and Deborah Pilkington.
By using annuals, grasses and vines, the plantings can be changed out to reflect the changes in the seasons, demonstrating how home gardeners can also keep their containers in use year-round. Even though the summer annuals are still going strong, we can’t wait to trade them out for some winter interest!
Photo credits: Deborah Pilkington, Joan Barber, Peter Gilmer, Lisa Nadler.