In addition to producing edible nuts, heartnut (Juglans ailantifolia), also known as Japanese walnut, can add shade and ornamental value to a garden. With its large compound leaves and sweet, heart-shaped, easy-to-crack nuts, this upright grower can get up to 60 feet tall during its lifespan of about 40 years. To allow them to thrive, grow heartnut trees in climates within U.S. Department of Agriculture plant hardiness zones 5 to 8. Even though heartnut trees can be started from seed, growing them from grafted trees in spring results in an earlier crop that's true to the parent tree.
Perform a soil test to determine the pH of the native soil. Use a commercial soil test kit or have a soil testing laboratory conduct a soil analysis for you.
Add sulfur to the soil to lower the pH, or add limestone to raise it. Work the amendment into the top 7 inches of soil with a shovel. Aim to reach a soil pH range between 6.5 and 6.8, which is ideal for heartnut trees.
Cultivate the soil in a sunny area of the garden that's sheltered from strong winds. Remove weeds and incorporate a 2 inch layer of compost into the soil to promote drainage. While preparing the planting area, soak the heartnut tree roots in water or cover them in moist peat to keep them from drying.
Dig a hole that's about 24 inches wide and 12 inches deep. The size of the hole must be large enough so the roots can naturally spread without breaking or bending. Spread out the heartnut tree roots in the hole and backfill it halfway. Tamp down the soil with your hand to remove air pockets.
Water the soil in the hole with a watering can or garden hose. Provide enough water to soak the area and reach the roots of the tree. Finish backfilling and lightly tamp the soil around the tree with your foot. Transplant the tree at a similar depth as it was in the nursery container.
Paint the trunk of the heartnut tree with white, water-based latex paint, to protect it from sunburn. Spread the paint from the bottom of the trunk up to the base of the first scaffold branch. Alternatively, wrap the trunk with aluminum foil.
Place two 7-foot long stakes in the ground on both sides of the tree. Maintain an 8-inch distance between the stakes and the tree. Loosely tie the tree to the stakes with fabric-covered tree ties.
Trickle water on the soil around the heartnut tree, once a week during its first summer. While the tree establishes, don't allow the soil to completely dry between waterings.
Spread a 4 inch layer of wood chips in a 4 foot diameter over the soil around the tree, to suppress weeds and promote soil moisture retention. Keep the mulch 6 inches from the trunk of the tree.
Fertilize the heartnut tree with a 10-10-10 fertilizer, in early spring of its second year and every year hereafter. Avoid fertilizing before or immediately after planting the tree, because this can damage the tree roots and stimulate too much growth, which can affect the tree's ability to make it through winter.
Your Planting Articles
Things You Will Need
- Soil test kit
- Sulfur of limestone
- Watering can or garden hose
- White latex paint or aluminum foil
- 7-foot stakes
- Fabric-covered tree ties
- Wood chips
- 10-10-10 fertilizer
- The University of Tennessee Agricultural Extension Service: Home Nut Tree Plan
- Edible Landscaping Online: Heartnut aka Japanese Walnut
- University of Kentucky Cooperative Extension Service: Nut Tree Growing in Kentucky
- Oregon State University Extension Service: Growing Walnut in Oregon
- Landowner Resource Centre: Planting and Caring for Nut Trees
- Tom Brakefield/Stockbyte/Getty Images