Black walnut trees are known for producing delicious walnuts and providing a shady space for relaxing on an afternoon. They are also famous for producing a substance known as juglone, which can be toxic and deadly to many plants if grown near black walnut trees. To plant near black walnut trees, you'll have to first determine what you can grow that you like and then select the proper placement in the ground for them.
Determine the types of plants you want to grow that fit your landscaping, such as shrubs, vines, ground cover, flowering annuals or perennials, or trees. You'll also need to know just how shady your walnut makes the area near it so you can select the appropriate plants for full sun, part shade or shade.
Choose plants that are tolerant of juglone. A few good plants to consider are weeping forsythia, rose of Sharon, clematis, Japanese maple, morning glories, pansies, bugleweed, hollyhocks, daylilies, hosta and Siberian iris.
Dig holes for your plants near your black walnut in areas where you aren't up against the trunk or directly against any of the roots. Make the hole for each plant twice the size of the pot it is in.
Replace half of the soil from the hole with compost or garden soil to give new plants a chance to acclimate to a lower level of juglone before it increases again over time.
Plant your selections of tolerant plants in the layout you prefer and fill in gaps around the root ball with compost or garden soil. Water each new planting well to saturate the soil around it and keep the plant moist for the first month.
Look over your plants once or twice a week after the initial planting for signs of distress or lack of growth. Juglone can affect plants in as little time as one to two months, so wilting of leaves or failure to grow should be spotted easily and the plant moved to a new location.