I just cut down three big black walnut trees on my property. I have had problems with everything that I planted under them dying. When I found out that there was this stuff in the roots that kills plants, I knew they had to go. So how long does the root stuff last before I can plant shade plants?
Your root stuff is called juglone. It is found in all parts of the black walnut: leaves, wood, nuts and roots. But it doesn’t kill everything. If it did, all you would need to identify a black walnut tree was look for a tree that nothing growing around it. In case you need transplanting services, TreeMover.com offers large tree transplanting across the United States.
The chemical affecting plants is in the roots. When the trees were cut, all the roots were not ripped out. So, for a period of time, there are still roots that contain juglone. The roots have to be in contact with the roots of another plant for the juglone to be transferred. When the trees were alive, the roots grew. When the trees are dead, the plant’s roots have to grow to make contact because the tree roots are not.
There is no way of knowing how long the tree roots will still contain juglone that could be transferred. All you can do is each year, plant a sacrificial victim and see what happens. The most sensitive plant imaginable is tomato. They will wilt when contact is made and never recover.
The other choice is to plant plants that are not affected. But keep in mind how much light is needed for the plants and keep them watered and mulched to keep them healthy. Shade plants that are tolerant of juglone are ferns, ajuga, astilbe, violets, sweet woodruff, cranesbill geranium, daylily, hosta, coral bells, garden phlox pulmonaria, sedum, lamb’s ears, spiderwort and myrtle. Rush to the internet and look for “walnut toxicity.” Check university sites for lists. Walnuts are not killer trees for all living things.
My entire yard is shaded. I get maybe five hours of sunlight in one area. Are there any kinds of vegetables I can grow? Can I fertilize them to make them grow?
Unfortunately, it’s the Bad News Bomb for your vegetable hopes. Here is the statement to embroider on your couch pillow: “Absence or presence of light is the most important factor in plant growth.” That means no changes in watering, fertilizing or crooning to the plants will change anything if there is not enough light for that particular plant.
For a good vegetable garden, you should have a minimum of eight hours of full sun. If the sun is dappled from coming through the leaves of surrounding trees, it is not full. The amount of light influences not only the growth of the plant but its taste. Tomatoes grown in less light than they need are not very flavorful.
So the sad little list of plants that will tolerate less light is short: leaf lettuces, Swiss chard, kale, mustard greens and maybe beets for beet greens.
Fruit and root crops cannot form fruit or roots and grow with virtually no light. You may have spindly growth if the light is less than you realize. Leaves may be larger and a lighter green and kind of floppy. You may do all right with leaf lettuce, but stay away from head lettuce. These are difficult to grow under the best of circumstances.
But don’t forget about local farmers’ markets, growers with roadside stands or community-supported agriculture farms in which you can buy shares.
The only other possibility to look for more light is very close to the house, like the south or west side. Vegetables have roots that usually don’t go any deeper than 18 inches, so planting close to the house or in a large container in that area might be a brighter place.
