Green Teacher 121 Page 3

By Cathy Law

AS THE GREEN SCHOOLYARD MOVEMENT is taking root, every teacher who has caught the bug faces the same daunting dilemma: garden mainte-nance. The fall and the winter season is when the school gar-den slows down and its caretakers can gratefully take a break from the relentless demands of their garden. But before you relax into rejuvenating your spirit (and will) for another year of gardening ahead, why not spend time planning how to save time next growing season by learning low maintenance tips for your garden? You’ll be glad you did!

Most school gardens feature vegetables that reach their grandeur just as the last school bell rings for the year. Tem-peramental under the best of conditions, vegetable gardens are unforgiving and needy. A huge amount of research has been done on the benefits of gardens for place-based educa-tion. Students learn better when they are outdoors enjoying themselves. According to Cornell Garden Based Learning, the benefits of garden-based learning include fostering eco-logical literacy, stewardship skills and higher exam scores.1 So how do we give our high school and middle school stu-dents authentic learning experiences in a school garden, without leaving its caretakers ragged? Perhaps looking to Nature herself is the solution. But you might have to ditch the tomatoes.

Our multi-purpose school gardenFor the past 12 years I have developed a school garden

using predominately native plants grown in natural sweeps of color, texture, and form. The benefits of not growing vegeta-bles (almost all of which are non-native in my region) is that you can select plants that have adapted to your climate and require a minimum amount of care. I also contend that grow-ing native plants that specifically attract pollinating insects and migrating birds can appeal to a larger audience of curi-ous learners and can present a wider range of potential lab opportunities. Our high school garden, named the Courtyard Gardens, measures 140 by 80 feet with half of the garden covered in paving stones. My students and I have arranged the plantings into themed zones, including scented, culinary, medicinal, touch, butterfly, shade, Zen, and geology gardens. Not only do these zones offer excellent sites for authentic scientific study, but our English, foreign language, art, math, and even social studies teachers enjoy bringing their classes out to the garden to learn. Without a doubt, a garden setting is a fantastic spot for place-based education, but how does one apply nature’s laws to designing a green schoolyard to ensure that the head gardeners spend their free time somewhere other than the school garden?

Living in harmony with the principles of nature means walking the edge between wild and cultivated gardening. Gardeners are pretty crazy people! No matter what you do,

Greening Your Schoolyard with Native Plants

How to maximize your school garden and minimize excess labour

Phot

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athy

Law

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you have to water, fend off insects, and be vigilant about removing invasive plants. But in the interest of having your garden and your free time, too, perhaps letting nature lend a hand in your maintenance chores and not striving for per-fection are effective guidelines for growing a schoolyard garden.

Strategies for native plant gar-dening include selecting plants that are well suited for your environment, judicious pruning and weeding, and using time-honored tech-niques to tamp down the enthusiasm of over-zeal-ous insects. Choosing native plants that act as hosts for native insects and building bug hotels keep your local ecology in balance and make learning more memo-rable for your students.

Grow native plantsThe single biggest impact your school garden could have on your summer plans is established when you plant your garden in the first place. Growing vegetables is a sum-mer-long commitment which co uld quickly lead to total disaster if your vegetables get too desiccated. However, selecting natives that border on xeriscape (needing little to no irrigation) gives you the advantage of nurturing plants that are well-adapted to your climate. With climate change impacting gardens’ health, summer can vacillate between wet to really dry. A semi-arid plant can tolerate a little too much rain, but moisture-loving plants will die if deprived of water. Of course, irrigation systems and rain gardens can broaden the range of plants you choose, but let’s assume you don’t have those resources. The kinds of native plants that will look as happy to see you in Sep-tember as they did in June are those that have adapted over thousands of years to grow in your region. While you are enjoying your first cup of hot cocoa this fall, spend time researching which xeriscape perennial native plants thrive best in the microclimate of your school.

But the exuberant growth of a native plant will not go noticed by you alone. Little chew marks and delicate holes riddling the leaves of your plants are evidence of a wider, more profound reason to garden with natives. Your oasis of greenery is a supermarket for native insects in search of a decent meal in their desperate bids for survival. While it may at first seem undesirable to have plants that attract insects, a healthy garden made of diverse plant life will show limited insect damage. Birds, spiders, and

other insects will lurk in your foliage feeding on your herba-ceous insects, and before long, you will support a complex food web of life.

Creating food sources for our native insects is of eco-logical importance on a massive scale. Sadly,

insects are experiencing an apocalypse of chilling proportions. In the last 25

years scientists have witnessed a reduction of flying insects

as high as 76%.2 The loss of food sources is one of the primary reasons. Very few native insects can feed on lawn plants and ornamen-tal trees and shrubs. And they certainly don’t recog-

nize fancy Asian plants and colorful cultivars that have

been bred to sport outrageous leaf patterns and colors. Research

done at the University of Delaware has shown that nativars (cultivars of

native plants) whose leaves were changed to red, blue, or purple showed a three- to five-fold decrease of insect foraging.3 Recent studies by Annie White of the University of Vermont also indicate that most native insects prefer the flowers of native species over cultivars.4 Further studies are underway, but it appears that the hybridization of native plants to include favorable characteristics such as mul-tiple flowers, extra petals, and longer bloom times genetically comes at the expense of nectar and pollen production.

Having plentiful insects in your garden from your stu-dents’ perspective is more exciting, too. They will be signifi-

cantly more engaged in learning about the food web if they are out in your garden hunting for examples of predation

as opposed to listening to you describe it inside the class-room. All you need is a hand lens and bug net

and your students will be memorably transported into the world of the

small and its complex feeding interrelationships.

Tough love and timely haircutsPart of the secret to a low-maintenance native garden is your attitude towards the garden. Seeing

yourself as a guardian rather than a gardener will keep you

from fruitlessly striving for a manicured garden of straight lines

and perfect specimens. Holding back from weeding every unexpected seedling

from your garden will give nature time to do what she does best: establish a flowing symphony of plants in a design that is a hundred times more beautiful than you could have planned. If you let your garden express itself naturally until you can determine what nature has in store for you,

Cathy’s A-list perennials

My greatest hits list of 10 native flowering perennials that grow well in the variable rainfall of

a sunny, dry meadow in Northeastern America include Penstemon digitalis (Foxglove Beardtongue), Baptisia

australis (Blue Wild Indigo), Cassia hebecarpa (Wild Senna), Echinacea purpurea (Purple coneflower), Pycnanthemum virginianum (Virginia Mountain-mint), Rudbeckia hirta (Black-eyed Susan), Vernonia noveboracensis (New York Ironweed), Helenium autumnale (Common Sneezeweed),

Symphyotrichum novae-angliae (New England Aster), and Asclepias tuberosa (Butterfly Milkweed). These hardy, fast-growing perennials perform

magnificently year after year and can hold their own with little to

no care.

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you will find wonderful repetitions of your favorite plants in locations that look stunning. However, selective weeding and timely pruning are key.

When you are faced with more work than you have time to accomplish, it is time for tough love in your garden. You certainly want to selectively prune any plants that are about to jettison an avalanche of seeds. One year of letting a pro-lific plant drop its seeds will create seven years of weeding. But removing the entire plant, especially if it doesn’t propa-gate through root systems, may not be necessary. The plant may only need a haircut below the seed heads to ensure less work for you down the road. Any time a weed overshadows a favored plant, simply pruning back the weed at the height of the plant you are trying to save will buy you time until you can front a full assault on the offending weed. Rather than renting a weed whacker, a Japanese saw-tooth sickle will cut even the toughest of stems like butter. Tool manufacturers such as Kusakichi have the construction of gardening tools down to an art, and I implore you to discover the time-saving delights of the right tool for the job.

One important exception to the benefits of giving nature time to express herself is when pernicious invasives have found their way into your garden. Removing invasive plants

such as Tree of Heaven, Japanese Honeysuckle, Purple Loosestrife, Bindweeds, Japanese Stiltgrass, and Canada Thistle (actually native to Eurasia) the moment you see them is your best line of defense. A garden’s best friend is your shadow, and it is much better to haunt your garden with vigi-lance rather than be haunted by a superweed that returns with vengeance year after year. But if your goal is to spend less time in your school garden, is there a way to keep these bul-lies at bay? Fortunately, yes!

Nature abhors a vacuumJust like how a freshly-plowed field invites weeds to grow, the vast spaces between your plants are an invitation for trou-ble. Killing weeds with herbicides is not allowed on school grounds. Besides, herbicides have the nasty tendency to cause harm to your desirable plants without touching the weed seeds. Freshly-exposed soil has thousands of weed seeds that only need exposure to the sun to germinate when you open the ground for planting. What is a time-saving, summer-lov-ing gardener to do? I have discovered four ways to reduce your weeding nightmare: 1) the stale seedbed technique, 2) mulching, 3) planting annuals, and 4) adding decorative boulders.

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If you can wait two weeks between clearing your garden area and planting it, the stale seed bed technique is a fabu-lous trick. The principle of this method is based on the fact that most weed seeds germinate from the top 2.5 inches of soil. After you’ve prepared your garden area, the second step of the stale seed bed technique requires you to sit back and do nothing. After a couple of wherein your weed seeds have germinated into a sea of tender white threads, it is time for your attack. On a sunny, dry day, run your rake gen-tly over your planting zone deep enough to kill the seedlings, but shallow enough so as not to bring up the deeper weed seeds. It is important to restrain yourself from till-ing the soil deeper than 2.5 inches — less is more in this case. Once the sun has dried out and killed the weed seed-lings, it is now time to plant on your nearly weed-free soil.5

After your plants are in the ground, a thick layer of mulch will suppress much of the remaining weeds, and as a bonus, mulch will increase the water retention and nutrients in your soil. The type of mulch you use depends on your budget and sense of aesthetics; shredded leaves, wood chips, compost, and bark mulch all work well. The only mulch I steer clear of is compost that has not heated above 140 degrees. Otherwise, you will find that you have just added an infusion of weeds that will leave you wishing that you owned a flame-thrower! Incidentally, using dehydrated manure from ruminating mammals such as cattle and horses is ideal because weed seeds can’t survive the passage through a lengthy intestinal track. A mulch layer between 2 and 4 inches works best; just be sure not to crowd the crowns of your plants, as this can cause root rot. Plant roots need air, too, and too much love can suffocate even the hardiest of native plants.

If your garden has just been planted and your plants are at the correct distance from each other, you are going to have major gaps of open soil until your plants flush out. And you know what grows in the meantime? Weeds! My favorite way to prevent this is to plant annuals such as Ange-lonia, Cosmos, Geraniums, or Marigolds that can stand up to the hot summer sun in the empty spaces. Lately, I’ve seen a variety of colorful, low-growing Zinnias in the nurseries. If you are budget-conscious, many annuals are wildly easy to grow from seed, and my students love to help sow seeds in containers and compare the marvelous diversity of seed

shapes and sizes. If you’ve ever started a Calendula from seed, you know what I mean! The important thing is to select annuals that harmonize in color with your existing perenni-als, but won’t grow so large as to compete with the growth of your beloved perennial natives.

The final method for weed reduction was a discovery I made quite by accident. The Courtyard Gardens was

initially constructed as a wildlife habitat and nature preserve for biological investiga-

tions by my students. But I quickly discovered that the more rocks

I put into the garden, the less weeding I had to do. The big-ger the rock, the better, so now large boulders make up a significant part of the garden. Our garden has a geology section that fea-tures sedimentary, igneous,

and metamorphic boulders, which are ideal for Earth

Science labs. The remainder of our garden contains boulders

designed with the principles of Jap-anese landscape gardening in mind.

Traditionally, rocks in Japanese gardens are used to evoke the feeling of a miniature, stylized land-

scape. Karesansui, or dry landscape gardening, uses rocks that are tall, arching, reclining, or flat. Some rocks mimic the feel of mountains, hills, lakes, and others symbolize Buddha himself.6 My students and I have also added stone bridges, rock “islands,” and “seaside” cliffs to our garden. The only species that are unhappy are the weeds! Suppressing plants in

the wrong places allows you to focus on helping plants you would like to see flourish else-

where, but you might have to enlist help from an unlikely source:

predatory insects.

Bug off through better real estateEven the most ecological-ly-minded gardeners have their limits with how much insect damage they can tol-

erate. Having pesky insect invaders destroy your favorite

garden plant is dispiriting. The usual solution of rotating your

vegetable plants on a yearly bases is not practical in a native garden.

One factor the native gardener has in their favor is diversity. Insect pests are fairly specialized

in what they like to eat, so if you grow 45 different plants and one or two are under insect attack, well, then you still have 43 or 44 more plants to enjoy.

A more direct solution is to see the presence of excessive herbivory as a symptom of a larger deficiency in your garden: the need for more native predatory insects.7 Even beneficial

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insects need a place to crash for the night, so why not build them a bug hotel? Bug hotels offer living spaces where ben-eficial insects can propagate (Yes, it’s that kind of hotel.) and overwinter successfully. Three years ago, my students built a 7-foot-high bug hotel that looks a lot like a wooden book shelf without a back board. My students then divided it into little cubbies and filled each cubby with different bedding materials to satisfy even the most discerning insect guests. These materials included bamboo sections, straw, pine cones, and even straight branches that were cut to lay cross-wise through the hotel. By allowing for a greater bug biodiversity, you can restore ecological balance and aesthetic beauty to your garden, not to mention create the perfect site for insect predation study.8 An informative website by Robin Horton of Urban Gardens on How to Design a Bug Hotel to Attract Beneficial Insects and Bees can be found at https://www.urbangardensweb.com/2016/02/27/how-to-design-a-bug-ho-tel-to-attract-beneficial-insects-and-bees/.

Last spring, our bug hotel was invaded by doves that con-tiguously built nest after nest in the hotel until mid-summer. This was especially exciting because the “dove” hotel was just outside our classroom window, so our students got to see the doves being raised from eggs to fledglings. This past spring, a Red-tailed Hawk perched for hours next to the hotel and spooked the doves into building their nests elsewhere, but not before one of the doves fell victim to the hawk. Now that the bug hotel is back in business for beneficial insects to sleep in peace, ravenous herbaceous insects will be on the decline once again.

No matter whether your focus is on vegetables or native plants, using gardens to teach is a phenomenal way to get students excited about learning. The advantage of grow-ing native plants in your green schoolyard is that you work with nature rather than insisting she grow under alien con-ditions that take a lot of effort to achieve. It is my hope that the prospective green schoolyard gardener not be dissuaded from starting a garden because of the time commitment. By switching to native plants, you benefit your local ecology, create a richer study site for your students and you make your life a little easier because natives want to grow in your gar-den. Selecting the right native plants and using time-saving horticultural techniques allows you to have your garden and your summer, too!

Cathy Law teaches Biology, Earth Science, and Field Biology at New Paltz High School in New Paltz, New York. She and her students started the Courtyard Gardens twelve years ago; it features over 200 different kinds of plants in 15 themed garden zones. The mission of the garden is to create an outdoor learning center dedicated to understanding and improving the environment and to enable learning that is problem-based and interdisciplinary.

Note: The author gratefully acknowledges Dr. Mike Jabot, Dr. Julie Henry, and the NYS Master Teacher Program for assistance writing this manuscript and to the Foundation for Student Enhancement for their yearly assistance in funding the Courtyard Gardens.

Endnotes:1. Cornell University, College of Agriculture and Life Sciences. Cornell Garden Based Learning. Benefits of Garden Based learning. http://gardening.cals.cor-nell.edu/program-tools/benefits-and-research/ Accessed July 23, 2019.

2. New York Times. Insect Armageddon. Editorial Board https://www.nytimes.com/2017/10/29/opinion/insect-armageddon-ecosystem-.html Accessed July 25, 2019.

3. Habitat Network. Nativars (Native Cultivars): What We Know and Recom-mend. Becca Rodomsky-Bish. http://content.yardmap.org/learn/nativars-na-tive-cultivars/ Accessed August 5, 2019.

4. Pollinatorgardens. From Nursery to Nature: Are Native Cultivars as Valu-able to Pollinators as Native Species. Annie S. White. https://pollinatorgardens.org/2013/02/08/my-research/ Accessed August 5, 2019.

5. University of Maryland Extension. The Stale Seedbed Techique: A Relatively Underused Althernative to Weed Management Tactic for Vegetable Production. Cerruti Hooks, Amanda Buchanan and Guidhua Chen. https://extension.umd.edu/learn/stale-seedbed-technique-relatively-underused-alternative-weed-man-agement-tactic-vegetable Accessed July 25, 2019.

6. Earthscape Inhabitant. Japanese Rock Garden. https://www.earthscapeinhabi-tant.com/japanese-rock-garden.html Accessed July 25, 2019.

7. Cornell University, College of Agriculture and Life Sciences. Cornell Gar-den Based Learning. Pollinator Friendly. http://gardening.cals.cornell.edu/gar-den-guidance/pollinator-protection/ Accessed July 23, 2019.

8. Urban Gardens. How to Design a Bug Hotel to attract benefical insects. Robin Plaskoff Horton https://www.urbangardensweb.com/2016/02/27/how-to-design-a-bug-hotel-to-attract-beneficial-insects-and-bees/ Accessed July 23, 2019.