Native, Nativar, Cultivar: What’s in a Name?

By Deborah Pilkington, EMGV

There’s been a lot of discussion recently about native plants, non-native plants, cultivars, and nativars. But what does it all mean?

There are two really important pieces to the definition of native plants:

First is location of origin:  A native plant is a plant that occurs naturally within a given area or eco-region. Thinking from large to small, we can we can talk about plants native to North America, native to the continental United States, native to the Eastern Temperate Forests, native to the Southeast, native to North Carolina, and native to the Piedmont area of North Carolina.

Second is the co-evolution over immense periods of time of that plant with native insects, bees, butterflies, and birds.  Why is this important?  Because native wildlife and native plants have a mutually beneficial relationship.  For wildlife, the plant provides food in the form of nectar, pollen, leaves, fruits and seeds.  It also provides housing in the form of hollow stems where insect larvae can overwinter, stems where caterpillar chrysalises can attach until a beautiful butterfly emerges, and cover and nesting places for birds.  In return, the wildlife ensures the reproduction and continuation of the plant species through pollination and the spreading of seed.  This relationship has evolved over many eras of time in a given eco-region.

A Nativar is a native plant that has been altered in some way by humans to produce a desired result.  Nativar is a term that denotes when a native plant is cultivated, i.e., selectively bred by human intervention. Native plus cultivar = Nativar.  What would a human want to change about a native plant, and why?  The why part first: To sell more plants.  The what? Here are some of the things that can be changed through cultivation of a plant:

  • Flower anatomy (size of openings for insect access)
  • Flower size
  • Flower color
  • Number of flowers on a stalk (e.g., double blooms)
  • Length of bloom time
  • Plant habit (upright, spreading)
  • Leaf color and variegation
  • Resistance to disease
  • Ability to produce seed
  • Increased fruit production
  • Increased fruit size

 So, what’s wrong with a beautifully colored, disease-resistant, double blooming, purple-leaved plant?  Nothing.  Except—remember the native wildlife?  Research has given us some interesting data on whether native wildlife can continue to be in a mutually beneficial relationship with these “new and improved” plants. 

First of all, altering the anatomy of a flower can impair the ability of insects to properly identify flowers, and access the pollen and nectar that those flowers may produce.

Secondly, native insects are often not able to eat foliage that has been bred to be purple, because it contains a chemical called ‘anthocyanin,’ and the insects do not have the ability to digest this chemical.

Thirdly, many of these nativars are sterile—that is, they don’t produce seed, so they don’t feed seed-eaters like finches, and they are short-lived.  They can only be reproduced by (human) cloning, so once the plant dies, you must buy a new one to replace it. Because these plants are reproduced by cloning, they are genetically identical.  Genetic variety across even plants of the same species allows the species as a whole to be better able to handle new or harsh conditions.  Large clonal plantings of nativars can easily be taken out when a new disease or pest moves in, or as environmental conditions shift as they are expected to due to climate change.

And finally, increased fruit size and fruit production has not been shown to benefit fruit-eating wild creatures.

On the plus side for nativars, a longer bloom time means more food over a longer period of time.  Increased disease resistance means plants that don’t succumb to common diseases.  It also means less need of “cides”, e.g., pesticides in the garden.  And in the case of a more upright plant, if the stems are left up over winter, it leaves more potential room for overwintering insect larvae.

Much more research needs to be done on whether the nectar and pollen that nativars produce are equal in food benefit to wildlife as the native species.

A non-native plant (also called exotic, alien, or introduced) is a plant whose origins are outside an eco-region.  Over many years, non-native plants have been imported from all over the world to grace and enhance American gardens.  A non-native plant brings challenges with it for our wildlife:  There has been no period of co-evolution, so our native wildlife may be unable to use the plant for food–case in point, a beautiful plant with perfect leaves (leaves that haven’t been munched on, sucked from, or generally disturbed in any way). Or it may produce fruit that is not only unhealthy for birds, but may also poison them instead.

Secondly, non-native plants may muscle away resources from native plants: sunlight, water, soil nutrients, and space.  In some cases, non-native plants may so ferociously outcompete native plants for these resources that the native plants die. These non-native plants are then often referred to as invasive.  Avoid these plants altogether.

* Resources and Further Reading

Print Resources

  • Tallamy, Douglas W., Bringing Nature Home: How You Can Sustain Wildlife with Native Plants, 2007, Timber Press
  • Darke, Rick and Doug Tallamy, The Living Landscape: Designing for Beauty and Biodiversity in the Home Garden, 2014, Timber Press
  • Mellichamp, Larry and Will Stuart, Native Plants of the Southeast: A Comprehensive Guide to the Best 460 Species for the Garden, 2014, Timber Press
  • Tallamy, Douglas W., Nature’s Best Hope: A New Approach to Conservation That Starts in Your Yard, 2019, Timber Press

Online Resources

  • Choosenatives.org promotes North American native plants in order to nurture healthy, balanced ecosystems and help restore natural habitats for all wildlife populations. Provides information on planting natives, advocating for critters, developing pesticide-free landscapes, identifying invasive aliens, and assisting Mid-Atlantic region gardeners in locating native plant nurseries and plant sales.
  • What’s in a Nativar (Carol Becker, Landscape Architecture Magazine) discusses the influence the native plant community had on the horticulture industry, research on nativars supporting insect and bird life, and the Migratory Bird Garden at Chicago’s Shedd Aquarium, including plant list.
  • Are Nativars OK? (Keith Nevison, Fine Gardening Magazine) a study of phlox nativars and a discussion on how cultivars might affect pollinators.
  • Mt Cuba Center a botanical garden in Delaware, whose expert researchers seek to expand the knowledge and appreciation of native plants and promote conservation.
  • Landscaping for Wildlife with Native Plants (NC State Extension) describes the problems associated with some non-native, invasive plants and presents a detailed list of native plants that may be used in place of these foreign ornamentals to attract wildlife to your property.
  • Wildlife Friendly Landscapes (NC State Extension) discusses landscaping for wildlife in urban settings, discusses native plants that can be used as an alternative to invasive exotics, points to resources for purchasing native plants, and includes a step-by-step guide for including native plants in your landscape.

Online Native Plant Lists

This post originally appeared as educational content for the Backyard Treasures Plant Sale.

Update on the 2021 Tomato Project

By Kathryn Hamilton, EMGV

For the last two years Master Gardeners have conducted tomato-growing experiments at Briggs Avenue Community Garden. In 2020 we compared the performance of grafted and ungrafted heirlooms tomatoes. You can read about the project and find links to our You Tube videos on grafting here.

With the 2022 seed catalogues arriving, the time seems right to catch up on 2021’s tomato experiment. Our goals were two-fold:  participate in the Citizen Science Initiative initiated by the Klee Lab at the University of Florida. Here we were charged with evaluating three tomatoes from the lab and comparing them to the most commonly grown tomato in the home garden:  Better Boy. For fun, we asked: “would the Klee Lab Hybrid come close to rivaling the taste of some of our favorite heirlooms?” For even more fun, we decided to see what type of tomato the Shin Cheong Gang, a grafting rootstock, would produce.

The tomatoes from the Klee lab included a large slicer (BW Hybrid), a mid-sized cherry tomato (R-Hybrid), and the improved Garden Gem, a salad tomato reported to be one of the best tasting tomatoes EVER. Here’s what we found:

B-Hybrid vs Better Boy

Throughout the summer the BW Hybrid (the Klee slicer) and the Better Boy ran neck-in-neck, standing stronger than any of the heirlooms. They were alive and ekeing out tomatoes in mid-September, a month longer than the last heirloom of 2020.  They had comparable production. The B-hybrid produced slightly fewer, but larger tomatoes than the Better Boy, which gave off more, but slightly smaller tomatoes.  During the period in which we weighed and measured them, there was a difference of one pound between the total weights of the two tomatoes.

In our annual, very informal Master Gardener, Tomato-Lover Taste Test, Better Boy was preferred over the BW Hybrid by almost 2 – 1. Those who liked the BW Hybrid called it richer and more intense than the Better Boy. Positive comments about Better Boy included: “Smoother, more tomatoey taste, and juicer.” To see what other Citizen Science Initiative participants thought, go here. Our comments are under the entry for Durham.

R-Hybrid vs Shin Cheong Gang

Without question, the Shin Cheong Gang, a rootstock, which we grew to try its tomatoes was the sturdiest and most productive plant in the garden. By size only, it was immediately recognizable as “different.” It produced bags of cherry tomatoes on a highly disease-resistant plant.

The Shin Cheong Gang vine was nearly 12 feet long. It produced bags of tomatoes. Given that rootstock tomatoes are notoriously bad, one taster called the tomato “good enough” especially given the plant’s productivity and disease resistance.
 

The cherry-type tomatoes from the RW Hybrid were a bit larger, but grew in vined clusters, making it difficult to pick the ripest tomatoes which grew to the inside. They were also terribly susceptible to cracking. In taste tests, comments for the RW Hybrid went from “good enough” to “strong intense flavor.” Comments on the rootstock tomato included: “bright flavor; tomatoey and sweet; and ‘I like this, just not as much.’”

The vining growth habit of the RW Hybrid was a harvesting liability, especially for tomatoes growing deep inside the plant. The cracking was legendary.

Garden Gem

In “garden munches” early in the season, Garden Gem didn’t seem like a very interesting tomato, although one astute Master Gardner recognized its “potential” almost immediately.  Ultimately, Garden Gem lived up to its name.  The plants were disease resistant, prolific, easy to pick, crack resistant. While they weren’t large, they were perfect salad tomatoes, juicy and sweet. And in October, this was the last plant standing in the garden.

The Annual Master Gardener, Tomato-Lover Taste Test

For the third year in a row, in an event organized and hosted by Bev Tisci, a group of master gardeners gathered mid-August to taste-test and rank tomatoes from their gardens. This year we tasted 38 different tomatoes: 21 slicers; four smalls; three pastes, and 10 cherries. Here are the results of the top three tomatoes in each category.

Slicers: Carbon, Costoluto Genovese and Blazey (from Craig LeHoullier).

Paste: La Roma; Cuore DiBuo; Premio

Small: Garden Gem, Marriage Marzinera; Juliet and Tiger Tom (tied).

Cherry:  Artisan Blush, Sungold, Black Cherry.

A few notes: 

  • This was the second year that Carbon ranked first among slicers.
  • In 2019, Pink Berkely Tie-Dye took first place, but was unranked this year.
  • Lemon Boy earned third place in both 2019 and 2020; it was also unranked this year.
  • And look at that Garden Gem!
  • Proven Winners is selling seeds and starts of the original Garden Gem. Go here for additional information.
  • The Klee Lab will once again sell seeds in support of their research and will continue their Citizen Science Initiative. For a $25 donation you will receive seeds for R Hybrid, BC Hybrid, Improved Garden Gem, Improved Garden Ruby and Better Boy Hybrid. Click here for additional information
  • Several companies are selling seeds for Maglia Rosa, which gives Garden Gem its flavor.
  • As of this writing (December 29) Shin Cheong Gang seeds remain out of stock. That was also the case in 2020. Last year, by mid-January both Johnny’s and David’s Garden Seeds had stock. But this year, David’s Garden Seeds reports that their supplier no longer carries them.

January: To Do in the Garden

By Gary Crispell, EMGV

And so ends another year of pandemic.  The light we saw in the tunnel in July turned out to be the Omicron Express and it has run over everyone.  Enough, already!  Just go away…please.  Sure, gardening is essentially a solo sport and it is generally done outside, but the part that is missing is the getting together over coffee and petit fours, or tea and crumpets or beer and nachos to tell our stories.  So many stories.  Save ‘em up, friends.  Surely this can’t go on forever.  (Can it?)

In the meantime, let’s go out and make some more stories.  Look, it was 70 degrees on New Year’s Day and it snowed on the 2nd.  Ya gotta love North Carolina weather.  Not a big deal, as there is only so much you can do outside in January anyway.  Let’s just do it so we can get back inside by the fire.

LAWN CARE

Complete the annual leaf removal ritual.  There’s nothing left on the trees except for some oaks and beeches which will be there until Spring.

Here’s my annual January PSA about reducing the amount of turf in your yard.  It is the most environmentally unsustainable planting in your yard (unless you have a mega planting of Chinese wisteria or maybe kudzu).  Dump the lawn and reduce the amount of phosphates, nitrogen, and pesticides washing into your/our drinking water.  The Earth thanks you in advance for your efforts.

FERTILIZING

Nope!  Well, there’s the wood ashes you can put on shrub and bulb beds if the pH is low (<6.0) and you would know this from the SOIL TEST you had done last Fall.

PLANTING

This exercise is largely dependent on soil moisture right now.  If it dries some you can transplant trees and shrubs.  Roots will grow as long as the soil temp is above 40 degrees.  Last week it was 60 degrees.

PRUNING

January is a fine time to prune, especially non-flowering plants.  Flowering plants should be pruned 4-6 weeks after bloom time.  Hand pruning is recommended.  I mean you aren’t going to take the yard-of-the-month award away from Biltmore, so unless you really have hedges, leave the hedge trimmers in the shed.  And if you do have hedges, wider at the bottom and narrower at the top for optimum growth.

SPRAYING

So, the plants you brought in the house in October were hosting guests that you now find objectionable.  It happens.  Their friends don’t necessarily have to be your friends.  Treat them with a light horticultural oil or insecticidal soap and if you can hustle them outside to do it, so much the better.  Otherwise, be very careful and always read and heed the label.

AND IF YOU CAN’T PLAY OUTSIDE

‘Tis the season of the seed catalog.  You know this because your mailbox is inundated with them.  There is always GOOGLE and the many fine articles on the NCSU Plant Toolbox with which you can entertain and inform yourself.  (You might even be able to pick up an education hour or two, but Dr. Troth will have to approve.)  Do some research and see if there might be a NC native plant or two that would fit into your landscape plan.  (I’m sure you have one of those!)  Make soup from the bounty of your summer/fall garden and share it with a neighbor and if the meteorological prognosticators use the “S” word, skip the French toast trio of bread, milk and eggs and stock up on hot cocoa mix.  Chocolate will get you through anything.

*Resources and Further Reading

How to Prune Specific Plants
https://content.ces.ncsu.edu/how-to-prune-specific-plants

NC Extension Gardener Plant Toolbox (find your perfect plant or figure out what that unknown weed is!)
plants.ces.ncsu.edu

December: To Do in the Garden

By Gary Crispell, EMGV

Well now it’s December
With scarce heat and light.
Short winter days.
Long winter nights.

Gardeners are wondering
What can be done.
The soil’s too cold
For dirt digging fun.

But wait!  Here’s a tale
With information in it.
Be still just now
And read it for a minute.

‘Twas the night before solstice
And all through the house
All of the gardeners
Were chasing a mouse.

The mouse that had eaten
The daffodil bulbs.
The mouse that had dined
On the prize-winning shrubs.

“We’ll catch it!”, one said,
“With sunflower seed.”
“We’ll cage it up.”
“It’ll never be freed!”

Now let’s cut to the chase.
(Oh, wait!  We’re already there.)
The mouse got away,
Its advantage unfair.

“Whatever shall we do?”,
The second gardener lamented.
“That damn little rodent”
I swear was demented.”

”I just checked the calendar,”
“There’s nothing to do.”
While the third gardener said,
“That’s not exactly true.”

The fescue can be mowed,
The leaves blown away
Which is always more fun
On a cold blustery day.

We still can plant
Some landscape shrubs
And if we hurry
Some late tulip bulbs.

We can prune the nandina
And red-berried holly.
They will make the house
Look festive and jolly.

Herbaceous perennials
We can now prune
For a flowery reward
Next May and next June.

Keep the sprayer
Hung up inside.
It’s too cold to spray
Those weeds that we spied.

Except for the lace bugs
All others are hiding.
‘Til warm weather comes
Their time biding.

The strawberries!  The strawberries!
They must be protected.
Lest they get frozen
And look all dejected.

A little pine straw
Or perhaps that of wheat
Will cover the plants
So we’ll have berries sweet.

Lime on the lawn
Will be just fine,
But skip the fertilizer
Until the warmth of springtime.

“And that about does it.”,
The Master Gardener said.
“let’s read a good book,”
Drink some tea and go to bed.”

“Tomorrow we’ll checkout”
“Catalogues of seed”
“And fill the containers”
“Where the birds feed.”

To all of our friends
Out there in cyberspace
May your holidays
Be filled with grace.

And may your next year’s garden
Be like my grandmother’s,
A bounty for you
With a large share for others.

*Resources and Further Reading

Organic Lawn Care Guide
https://content.ces.ncsu.edu/organic-lawn-care-a-guide-to-organic-lawn-maintenance-and-pest-management

North Carolina Extension Gardener Handbook – Small Fruits
https://content.ces.ncsu.edu/extension-gardener-handbook/14-small-fruits

How to Prune Specific Plants
https://content.ces.ncsu.edu/how-to-prune-specific-plants

NC Extension Gardener Plant Toolbox (find your perfect plant or figure out what that unknown weed is!)
plants.ces.ncsu.edu

Native Fall Foliage Color in the Piedmont

By Wendy Diaz EMGV

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[1] especially against our brilliant blue Carolina sky.

White Oak (Quercus alba) in my woodland home garden. Photo by Wendy Diaz on November 24, 2021.
Red Maple (Acer rubrum) on my street in Durham, North Carolina. Photo by Wendy Diaz on November 24, 2021.

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.

Winged sumac (Rhus copallinium) behind bench in back yard. Photo taken by Wendy Diaz on October 27, 2021

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[2].

View of tree canopy in northeast corner of my yard: American Beech, Loblolly Pine, Post Oak, Hickory, White Oak and in the foreground an understory Eastern Redbud. Photo by Wendy Diaz on November 12, 2021.
Backyard facing east of Dogwood and Eastern Redbud understory (mid-level trees) and Arrowwood shrubs. Photo taken by Wendy Diaz on November 21, 2021.

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[3]. 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[4]. 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 anthocyanins and 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[5]. 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. 

Fallen American Beech dead leaves beneath a Beech tree after a hard frost. Photo taken by Wendy Diaz on November 24, 2021.

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[6]. Leave your leaf groundcover and conserve this valuable natural resource[7] and if you live in Durham don’t forget to make the pledge to keep your leaves[8]. 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.

American Beech branches embracing a tall Pine tree beside Paul Green’s Cabin at the North Carolina Botanical Garden. Photo taken by Wendy Diaz on November 21, 2021.

[1] Fothergilla ‘Mt Airy’ – Spectacular Orange Autumn Color – Southern Style

[2] Using Fall Color in Your Landscape Design by John Monroe former owner of Architectural Trees Triangle Gardener September-October 2016 page 15

[3] https://content.ces.ncsu.edu/extension-gardener-handbook/glossary

[4] How Plants Use Light for More Than Just Energy by Matt Jones, Horticulture Extension Agent of Chatham County Center Triangle Gardener September-October 2019 page 24

[5] https://climate.ncsu.edu/blog/2019/10/the-leaves-they-are-a-changin-but-why/

[6] https://durhammastergardeners.com/2021/11/17/leave-your-leaves/

[7] To leave or Not to Leave November 15, 2021 WDD https://durhammastergardeners.com/2015/11/

[8] https://keepdurhambeautiful.org/pledge-to-leave-your-leaves