Black Walnut plantations can be established by either planting seeds or by planting seedlings. For extensive tree planting information, the Walnut Notes from the USDA Forest Service have a number of notes on the topic. Planting and Care of Fine Hardwood Seedlings is a series of 20+ guides developed by the Hardwood Tree Improvement & Regeneration Center.
Choosing a Good Walnut Site
One of the black walnut grower's most important decisions is where to plant this valuable, but sensitive hardwood. Black walnut has specific soil-site requirements that must be considered when locating a planting site. It grows well only on land of good quality. Briefly, black walnuts grow best in soil that is:
- medium textured
- deep, well-drained
- not stony
- on lower north- or east-facing slopes (avoid planting on rolling, hilly ground) not compacted
Should a grower plant black walnut seeds...or black walnut seedlings? There's no one right answer, but planting seeds offers several advantages over planting seedlings:
- Seedlings from seeds develop normal taproots.
- Seeds are easier to store and carry to the planting site.
- Seeds can be planted in the fall or in the spring after stratification.
- Seeds of selected, high-quality trees can be planted instead of run-of-the-mill seedlings.
There are a number of steps to take before planting seedlings:
- Prepare and lay out the planting site
- Order seedlings
- Prepare the seedlings
- Plant the seedlings
Planting Seedlings provides specifics to take you through the planting process.
Most plantations are established using bareroot, nursery-grown seedlings because it's more predictable than planting containerized stock (see Growing Containerized Seedlings). Black walnut seedlings may be obtained from most state nurseries in areas where walnut is found naturally. Contact your local extension agent or State forester to find out if walnut seedlings are produced in your state. Seeds or seedlings may also be obtained from commercial nurseries. Note: prices differ substantially depending on whether seedlings are grafted varieties selected for fast growth or "run of the woods" seedlings grown from seed.
Black Walnut Cultivars
Cultivars are the products of vegetative propagation of a clone, of selection of a race, or of controlled breeding worthy of a separate name. More than 400 black walnut cultivars have been named in the past century, most for increased nut yield or quality. Walnut growers interested in producing nuts might achieve better yields by planting cultivar seedlings instead of bed-run nursery seedlings. Cultivars for timber are also available, selections for good form, rapid height, and diameter growth, primarily for faster timber production.
Information adapted from Walnut Notes, Burde, E. Lucy, 1988. Source: St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station.