Like most newbie gardeners, we were intent upon growing our own tomatoes and peppers. Because the nightshade family is highly sensitive to juglone, a chemical secreted by black walnuts that interferes with respiration and photosynthesis in susceptible plants, we knew raised beds would create an environment where the tomatoes and peppers wouldn't wilt and die.
So, two years later -- after shoveling soil, hauling manure and building stone walls, our first tomatoes and peppers settled into their new home: Four, amoeba-shaped stone beds filled with a rich mix of compost, manure and clay soil.
From there, it was a swift evolutionary process: We added zucchini, basil, garlic, then beans, lettuces, radishes, beets and cucumbers. As our desires and appetites grew, we embraced the idea of perennial vegetables and fruits -- asparagus, rhubarb, blueberries, stone fruits and apple trees.
To accommodate that range of plants, we expanded into the front yard, transforming a once sprawling lawn into an edible landscape transacted by winding pathways that frame four main growing areas to make rotations a bit easier to track.
But as we've struggled to create a mini-orchard near the initial raised beds, our attention has returned to those massive black walnuts. Although our fruit trees are uphill from the walnuts and beyond their drip line, I fear juglone may still be responsible for our woes. This alleopathic chemical the walnuts use to limit competition may be stunting our fruit trees' ability to thrive.
At a fellow gardener's suggestion, I've been exploring the merits of plant guilds. These purposeful groupings take advantage of plants' natural interplay, thereby creating garden buffer zones such as might exist in a wild forest.
One of the most discussed relationships in plant guilds involves black walnuts, mulberries and apple trees. Native red mulberries can live perfectly happily under the canopy of a black walnut, impervious to juglone's effects. And, their root zones serve to mitigate the damaging impact of juglone. Their presence, then, can create a healthier environment for apple and other fruit trees.
Weaving mulberries into the fabric of our landscape will take a bit of doing: More soil rearrangement -- which we do by hand with shovels and a wheelbarrow.
But if the result is a happy orchard of apples, sweet and sour cherries, plum and pear trees, it'll be worth it.