Dry Shade Solutions

Epimedium blooms in late April and May.  These leaves often persist through winter.

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How do you turn the dry, shady areas beneath trees and large shrubs into beautiful garden spots lush with color and texture?  That is one of the toughest challenges for many gardeners.  Most ornamental plants want plenty of sunlight and moisture to thrive.  What to do when the thirsty roots of large woodies soak up the moisture from the soil, and their dense canopy cuts off the sun?

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Athyrium niponicum grows with Saxifraga stolonifera in dry shade under a hedge of large shrubs, just a few inches from our driveway.

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Many of us gardening in established neighborhoods face this challenge.  Our shady spots may be under trees, near foundations, in the shade of a neighbor’s home, or around overgrown shrubs.  If we try to maintain a lawn, it’s thin and patchy.  Weeds invade where grass is slow to grow.

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Gravel makes for a very good mulch over newly planted areas, especially on sloping ground.

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If we give up and do nothing, then we’re left with these ugly, bare spots in our yard that may even begin to erode after heavy rains.   There are ways to work with these areas to transform them from bare to beautiful.

Luckily, there are some reliable perennials that will grow well in dry shade if we give them just a little encouragement.  A useful garden mantra, ‘Right plant, right place!’ is the first key to success in dry shade.  We can also make the spot a little more accommodating and dress it up a bit with some simple infrastructure.

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Have you ever noticed how the ground under a rock is cool and moist?  Rocks, bricks, pavers and gravel all help hold moisture in the soil.  Using these to border and build your planting area will help conserve moisture and provide cool, moist places for the roots of your shade perennials.

Simply laying a single layer of landscaping bricks around the area you plan to cultivate begins the garden making process.  You can also use large rocks,  cinder blocks, wood, or even shallow pots.  If you use cinder blocks or pots, fill the openings with compost or potting soil and plant them up, too!

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The stump garden begun in 2015 with a pair of ferns has grown into this beautiful section of our fern garden, as it was in May of 2018. Once begun, gardens tend to expand.

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After you outline the new bed, spread a few inches of compost to improve the soil, hold moisture and provide a little more depth for planting the roots of new plants.  You can’t dig it in if you are planting over the roots of a tree or large shrub, but don’ worry.

Earthworms and other invertebrates in the soil will appreciate the compost and move it down into deeper layers of soil for you.  Adding an inch or so of fresh compost each spring will help improve the soil further with each passing year.  If there are weeds or grass in the area already, then lay some paper grocery bags or several layers of newsprint over the existing vegetation and then cover the paper in compost.

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Butterfly garden in March 2012, trimmed, weeded, and with a fresh topping of compost.

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Care must be taken to not bury the woody roots too deeply.  They don’t like that!  You also can’t pile compost or mulch up the woody trunk of a tree without harming it.  ‘Mulch volcanoes’ climbing tree trunks and burying roots invite disease and weaken a tree.    Keep your new layer of compost a few inches away from the root collar and trunk of any nearby trees or large shrubs.

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If you can only dig a few inches deep in an area where you want to place a well rooted plant, consider partially burying an attractive clay pot.  If you can enlarge the drainage holes without breaking the pot, do so and allow the plant’s roots room to escape and find their own way deeper into the soil.  Planting this way can also protect tasty plants from moles and voles.  I sometimes use this strategy for tender Hostas and Caladiums, that want to stay moist all of the time.

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This experimental raised bed under a dogwood tree is bordered with hypertufa planters and planted with a combination of hardy Begonia and ferns, with a few Caladiums planted each spring.

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The pot helps you create a soil ‘microclimate’ for these particular plants.  Those pots also help other plants near them.  Unglazed terra cotta can absorb and hold water, releasing it back to the soil and roots as needed.  Likewise, if you place decorative pavers, stones, planters, etc. within the bed, they will also help to hold moisture and roots can grow under them.

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“Soil security”

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If you are planting on a dry, shady slope, use this idea to create terraces.  Each terrace will hold some of the rain water that otherwise would simply run off.  Planting behind the pavers or timbers used to create each terrace offers a moist spot for roots.  I’ve also used pieces of broken pots to create planting niches on  a slope.  Once the roots grow in, after a season or two, you can often remove the broken pot to use elsewhere.

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The terraces help stop erosion, holding moisture behind the stones long enough that it sinks in rather than just runnimg off.

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Choose plants in small pots.  Given a choice between a 2″ pot and an 8″ pot, choose the smallest size available.  You may not be able to dig a very large hole, and the smaller root balls will be easier to plant.  Sometimes you can knock a new plant out of its pot and divide it, then plant the smaller sections, with their roots.  Check to make sure that each crown or stem has some roots attached before separating it from the parent plant.  This will work with many vines, with Hostas and with many ferns.   You can cover more ground initially with fewer new plants by dividing as you plant.

Use a sharp, narrow digging tool.  You might use a butcher knife, a hori hori, or a narrow trowel to dig out small areas between roots for new plants.

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Larger potted perennials can often be split into divisions and planted in much smaller holes.

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Also choose a couple of plants that will quickly spread out as ground cover.  Some plants, like Lamium, or dead-nettles, will grow quickly and strike roots at the leaf nodes.  This is a good strategy for plants to survive in dry shade, because they have lots of roots supporting their stems, leaves and flowers.  Once you have this established, you can easily dig up divisions, with roots, to move around.  Vinca minor will also grow this way and bloom each spring.  These plants can become invasive, so plan to keep their growth contained so they don’t overwhelm other plants in your scheme.

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Ferns and Lamium grow in one of the shadiest areas of our garden, below a stand of hazel trees.  From this small beginning in 2014, the Lamium spread out to cover a very large area. It grows a bit further each year, carpeting a dry, shady area where its needs are met.

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Plants like Ajuga and Saxifraga spread by stolons.  Each rosette of leaves strikes its own roots, but several stolons, or runners, will radiate out from each plant, forming a new little plant at the end of each of these creeping ‘stems.’  A thick mat of plants will form within a few years.  You can dig up any rosette, once it has a few leaves, and transplant it to another area.

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The Lamium spread to cover the entire area after just a few years.

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There are a surprisingly large number of flowering plants that will grow in ‘dry shade.’  Some will need moist soil for the first year or two as they establish, and then once their roots grow deep, they can survive on their own without a lot of extra water during dry spells.  Native gingers, hardy Cyclamens, ivies, Hellebores, Pachysandra, Liriope, Epimedium, perennial Geranium macrorrhizum, and some spring bulbs like Hycinthoides (Spanish bluebells) and Muscari will thrive.

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Saxifraga spreads by stolons

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Italian Arum thrives in dry shade from September through May, but will disappear during the summer.  You might balance it with Hostas , which will emerge just a few weeks before the Arum fades, or with Caladiums.  Mayapples, Podophyllum, will appear in March and disappear by July.  But their striking leaves add drama to a planting in the shade.  Highly poisonous, deer and rabbits won’t touch them.

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Mayapples and Vinca cover the ground in this narrow area under large Azalea shrubs.

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Hostas will grow well once established, thought they can’t stay dry for extended periods of time.  Heucheras and Tiarellas will also grow well in partial shade.  They will bloom better if they get some sun in the early spring.  If you have rabbits or deer browsing in your garden, you will need to protect the Hostas and Heucheras with animal deterrents.

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Although we may think of ferns as plants for moist areas, some will perform well in dry shade, too.  Native Christmas ferns, Polystichum acrostichoides, Japanese painted ferns, Athyrium niponicum, and autumn fern, ‘Brilliance’ are among those that do very well in dry shade.

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Plants growing in dry shade will most commonly bloom in late winter and early spring, before the leaves on deciduous trees grow back into a thick canopy.  During the rest of the year, the garden depends on foliage color and texture for its interest.

When designing for dry shade, consider the various leaf colors, textures, plant heights, and shapes to design a harmonious composition.  You might create a very restful, harmonious scene by repeating the same limited palette of plants over the entire area.  You can also create drama with dramatic foliage plants like Caladiums and Hosta.

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Many dry shade plants are evergreen, holding their places throughout the year.  But plan for winter when deciduous ferns die back, and also for the months after spring ephemerals disappear.  As in other parts of the garden, a little pre-planning allows the display of flowers and foliage to shift and change throughout the gardening year.

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As our climate shifts and summers grow hotter, shade gardening will become more important for maintaining our own health and comfort.  Large trees help shelter our homes and gardens from summer’s sun.  We may not be able to grow velvety lawns beneath the trees, but we can certainly create beautiful plantings in their shelter.

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As you find tough and beautiful plants that work well in your own microclimate, use them again and again to create a sense of unity throughout your garden.  If these are plants that you can easily propagate or divide, you soon realize that this is a thrifty way to create beauty in those challenging spots in your garden.

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Woodland Gnome 2019

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…and Fertilizer for Free

Chipped up wood and leaves spread over a foundation of bark, roots and branches will rot into good compost over time.

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I spent far too many hours of my youth watching Mark Knopfler  and Gordon Sumner sing, “I want my money for nothing, and my chicks for free!”.  MTV was brand new in those days, and I was utterly fascinated by the up-close view of the artists performing and the dreamy vignettes hyper-produced to sell their tunes.

Fun fact:  Gordon Sumner, better known as Sting, co-wrote that tune with Knopfler.  A former teacher, Sumner’s music career was just taking off as I began my own classroom teaching years.  He inspired me….

These were the days when Ted Turner was still trying to prove his idea that the public would support 24/7 journalism as entertainment over at his new CNN cable channel, and I was still living in a tiny walk up city apartment with only a few potted plant to soothe my achy, throbbing thumbs.  The world was filled with delicious possibilities.

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Well Knopfler and Sumner have aged, while I have not.  They still perform and I happily preside over our little Forest Garden.  They may have become unimaginably wealthy, but I have learned how to get fertilizer and plants for free!

I’ve left my classrooms behind, but will happily teach you how to perform the alchemy of soil for yourself, if you care to know the secret.  The world remains filled with delicious possiblities!

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It is all in how you look at things.  You probably understand that simple, but profound statement from your own experiences.  What seems free from one point of view, becomes costly from another.  What at first appears costly, ends up providing many more side benefits than expected.

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Let’s take fertilizer as an example.  Yes, I admit to the bags of Plant Tone, Rose Tone, Holly Tone, Bio-Tone Plant Starter With Mycorrhizae and a precious little jug of Neptune’s Harvest wintering in our garage.  Then there is the jar of Ozmocote, and the secret stash of crystallized orchid food hidden under the kitchen sink; a snack for when I want to coax the cohort of potted plants in our living space to bloom.  No, none of those were free.  In fact, if you added up what I spent on  all of them combined, they would likely buy a nice new pair of work boots….

And that was not the only ‘cost’ involved in these plastic bags and bottles of plant nourishing products.  They all came from factories.  Many of the ingredients were mined out of the earth.

Although these are ‘organic’ formulations, huge amounts of energy were invested in harvesting their components, creating the fertilizer, packaging it and transporting it to our local shops.  After the product is used up, there is some contaminated plastic packaging that won’t decay and must be put somewhere.  Those are costs we don’t see, and ones rolled into the price we pay.

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Gravel and Plant Tone ready to be mixed into the bottom of the planting hole.

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Now, if I use too much or time my application incorrectly, a lot of that product will simply wash away from my garden and into the creek.  Fertilizing our waterways increases algae growth and upsets the chemistry of the natural waterways.  Run-off of fertilizers has a profoundly negative effect on our lakes, rivers, the Chesapeake Bay, and even the oceans.

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Phosphorous, the P on your fertilizer bag, has an especially damaging effect when released into the waterways.  It initially stimulates the growth of algae and other plant life, which eventually shades out plants living on the bottom.  As this overabundance of plant life dies and sinks to the bottom and decays, it ties up oxygen needed by animal life, and destroys their food supplies.

Which is ironic.  Phosphorous is essential to plant growth, remains a key component of all commercial fertilizers, and is in limited supply.  Experts predict that our known supply of rock phosphorous that can be mined for industrial use will run out before 2200.

Phosphorous was ‘discovered’ in modern times by German alchemist Hennig Brand, in the late seventeenth century, from his experiments with human urine.    He eventually produced a white substance which glowed in the dark and burned brilliantly.  He called it ‘phosphorous mirabilis’, which means ‘miraculous bearer of light.’

Phosphorous is present in living tissue, and so may be found in urine and bone.  You may have heard about the ancient gardeners using human urine to fertilize their gardens.  This practice is discouraged today, of course.  But recall that animal waste products remain an essential ingredient in agriculture around the world.  Many of the ‘organic’ fertilizers contain rock phosphate or bone meal as essential parts of their formula.

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College Creek

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Phosphate in the soil isn’t always readily available to plant roots.  It must go through further biochemistry to make it available, and this happens best in living soil filled with microorganisms.   It happens best when the soil’s pH remains between 6.5 and 7.

Potassium, the K on your fertilizer package, is formed in supernova explosions.  It is both a metal and a salt.  In its pure elemental form, it reacts violently with both water and oxygen.  It is an extremely common element on earth, is found in all living things, and is an essential part of the biochemistry of all life.  Potassium in fertilizers appear as potassium chlorides, sulphates or nitrates.

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How is the average gardener to know whether or not their soil’s pH will even allow the plants access to any available phosphorous, nitrogen or potassium, and whether any additional nutrients are  needed?  That is why a soil test can give us invaluable information about our soil, and how to make it better.  Any local Extension office will gladly help with kits, instructions, processing and interpreting your soil test, and all states offer this service at a modest cost.

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Knowing what nutrients your soil may lack, to grow specific types of plants, allows a gardener to add only what is truly needed.  We can stop over-fertilizing, or adding fertilizer that never becomes available to our plants because of the complex chemistry of our soil.

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Fresh compost piled on top of existing mulch allows me to plant in this area without digging into the clay. A light covering of wood chips from the forest floor mulches the planting and makes the new bed visually “disappear.”

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Most experienced gardeners will tell a newbie:  “Feed your soil, not your plants.”  At first, this makes no sense.  But as you begin to understand the complexity of the soil as a living organism, it makes perfect sense.  Good soil is alive!

It is alive with microscopic bacteria, fungi, and tiny invertebrate animals that continually recycle Earth’s elements and make them available to fuel new growth.  Although some part of the soil is made up of tiny grains of mineral like sand, or granite, or clay; a large part of good soil is composed of decaying organic matter.

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Soil is alive, and improves as you add organic matter each year.

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These may be decaying roots or leaves, dead ants, or compost you’ve made from kitchen scraps.  It may be animal manure or even animal remains.  It may be a cover crop turned into the soil, bark mulch, hay or grass clippings.  Anything that once lived may eventually feed the soil.

And because all of these things contain the elemental building blocks of life, as they decay, their chemical components are released for re-use.  In addition to the big three of nitrogen, phosphorous and potassium, plants need many other elements and trace minerals naturally found in good, active soil.

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Mayapples appeared through the leaf mulch

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We can re-charge our soil with the nutrients necessary for plant growth in several ways, without having to purchase plastic bags filled with commercial fertilizers.

1. Grow and compost plants with deep roots.  Certain plants grow especially deep roots, which means they can access and absorb minerals deep into the soil, far below the area we cultivate.  As they grow, these minerals are stored in their plant cells.  Harvesting and then composting these plants enriches our soil.

Consider growing plants such as alfalfa, comphrey, parsnips and other root vegetables, purple coneflowers, and dandelions.  Trees with deep taproots also absorb minerals, which are stored in their wood and leaves.

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Comphrey’s roots extend for several feet into the soil, mining minerals that are stored in leaves and stems.  Comphrey attracts pollinators, is a medicinal herb and a great addition to compost.  Also use it as mulch around plants that need a boost.

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2.  Encourage earthworms.  Earthworms eat and digest organic material, and their droppings enrich the soil.  This greatly speeds the decomposition process and makes nutrients available to plant roots much faster.

Worm casting also contain beneficial microbes that work with plants.  Worms also loosen the soil and aerate it as they move around.  Worms will come to the surface to eat, but will also tunnel to a significant depth as they go about their lives.

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Organic matter left on top of the soil attracts earthworms.  Worms will feed at the surface, so long as it is deeply shaded, but live below ground.

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3.  Sheet compost over areas you plan to cultivate.  Sheet composting simply means laying organic materials directly on the soil where you want them to decay.  This organic material attracts earthworms and other decomposers to live and eat in this area, enriching it.

All organic mulch, whether straw, grass clippings, chipped leaves, bark, seaweed, coffee grounds, tea leaves, kitchen scraps, egg shells, sticks and branches or alfalfa pellets may be considered components in sheet composting.  I like to lay brown paper or black and white newsprint over the area first, establish the borders, and then pile materials in a ‘sheet’ over an area I intend to use later for growing new plants.

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4.  Grow plants that fix nitrogen in the soil.  All plants breathe.  Plants inhale through tiny holes in their leaves and use elements in the air, such as carbon and nitrogen for their growth.  When they exhale, they release oxygen and water vapor back into the environment.

Once plants have inhaled carbon, it is fixed into the walls of each cell.  But some plants are able to store nitrogen on their roots.  All members of the pea or legume family, Fabaceae, fix nitrogen, the N on the fertilizer bag, on their roots.  This nitrogen enriches the soil, and often may be used by plants growing nearby.   Fungi living in the soil assist with the transfer of soil nutrients and water between plants.

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Native Wax Myrtle fixes nitrogen from the air on its roots, making the area around each shrub more fertile with each passing year. Plants growing nearby can use this nitrogen, thanks to fungi in the soil which help transfer nutrients and water between plants. Fallen leaves also further enrich the soil.

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Members of this family include crops such as peas and beans, peanuts and lentils.  But it also includes flowers like lupines, and several shrubs and trees like black locust, acacia and mimosa.  I recently learned that the wax myrtle also fixes nitrogen on its roots, enriching the soil.

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Our native redbud, Cercis canadensis, also fixes nitrogen on its roots, enriching the soil for plants growing nearby.  It is a member of the Fabaceae family, and its seed pods may be eaten.   This seedling can eventually grow into a small tree.

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Planting, or allowing, plants to grow that ‘fix’ nitrogen in the soil enriches the soil with that most necessary element for good plant growth- Nitrogen (N)- for free!  Nitrogen, always present in the atmosphere, can be captured and packaged by plants in our garden, and kept at root level, available to all that need it and naturally enriching our garden’s soil.

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Clover growing in the lawn is also fertilizing it.  In addition to feeding pollinators and small mammals, clover fixes nitrogen along its roots.

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Here is a partial list of plants that perform this little miracle:  all clovers, sweet peas, vetch, bush clover, Wisteria, golden chain tree, Judas tree, honey locust tree, Kentucky coffee tree, alder, some roses and many members of the gourd family, such as squash and pumpkins.

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Native Wisteria frutescens growing at the Williamsburg Botanical Garden fixes nitrogen in the soil along all of its roots.

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If you can plant food or flower bearing plants, which also fix nitrogen to improve the soil, you have multiplied this natural wealth for your own use.

Nature’s gifts surround us.  The more we understand about the living ecosystem we inhabit, the more we can work cooperatively with our environment to cultivate and enrich the web of life.  The more we learn, the more we can disengage with costly commercial suppliers, and find ways to accomplish our goals in harmony with nature.

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Woodland Gnome 2019

 

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