Juglans nigra was used for gunstocks, fencing, airplane propellers, and cabinets; currently, it is used for quality furniture, veneers, cabinets and indoor furnishings, and gunstocks. In addition, its nuts are used for foods and candies, and abrasives. Native Americans used this plant medicinally, for dyes, and as an insecticide.
Black walnut is deciduous tree growing 70 to 150 feet tall. Male and female flowers are separate on the same tree. Many male flowers are grouped into long, green, caterpillar-like clusters (catkins), and two to five light green, female flowers are grouped on very small spikes. The tree begins flowering when the plant it mature at about eight years of age.
Black walnut grows in rich bottomlands and fertile hillsides, in deep, moist, well-drained soils. It is shade intolerant.
Black walnut is a USA-NPN regional plant species. Regional species are ecologically or economically important and are distributed more locally than calibration species. The NPN integrates these observations to better understand plant responses within the different geographic regions of the nation. In addition, this species is an allergen. Observations on its phenology will provide valuable information to benefit people with allergies and the public health community.
If drought seems to be the cause of leaf color or fall for a plant, please make a comment to that effect.
This species has separate male and female flowers. If you know whether the flowers you are observing are male or female (or both), please make a comment to that effect.
Do you see...?
Breaking leaf buds One or more breaking leaf buds are visible on the plant. A leaf bud is considered "breaking" once a green leaf tip is visible at the end of the bud, but before the first leaf from the bud has unfolded to expose the leaf stalk (petiole) or leaf base.
How many buds are breaking?
Less than 3
3 to 10
More than 10
Leaves One or more live unfolded leaves are visible on the plant. A leaf is considered "unfolded" once the leaf stalk (petiole) or leaf base is visible. New small leaves may need to be bent backwards to see whether the leaf stalk or leaf base is visible. Do not include dried or dead leaves.
What proportion of the canopy is full with leaves?
Less than 5%
5-24%
25-49%
50-74%
75-94%
95% or more
Increasing leaf size A majority of leaves on the plant have not yet reached their full size and are still growing larger. Do not include new leaves that continue to emerge at the ends of elongating stems throughout the growing season.
What proportion of full size are most leaves?
Less than 25%
Colored leaves One or more leaves (including any that have recently fallen from the plant) have turned to their late-season colors.
What proportion of the canopy is still full with green leaves?
Falling leaves One or more leaves are falling or have recently fallen from the plant. More...
Flowers One or more fresh flowers or flower heads (inflorescences) are visible on the plant. Flower heads include many small flowers that usually do not open all at once. Do not include wilted or dried flowers that remain on the plant, or heads whose flowers have all wilted or dried. For Juglans nigra, the male inflorescence is a catkin which is initially compact and stiff, but eventually unfolds to become longer and hang loosely from the branch. Female flowers are very small and petal-less, emerging at the tip of a growing stem.
How many fresh flowers or flower heads are present?
Open flowers One or more open fresh flowers are visible on the plant. Flowers are considered "open" when the reproductive parts (male stamens or female pistils) are visible between unfolded or open flower parts. Do not include wilted or dried flowers that remain on the plant. For Juglans nigra, the male flowers will open once the initially compact catkin has unfolded and is hanging loosely. Female flowers are open when the pistils are visible, but will be very difficult to see where they are out of reach.
How many fresh flowers are open?
Peak flower: The plant has a large number of flowers and one half (50%) or more are open and still fresh.
Pollen release One or more flowers on the plant release pollen when gently shaken or blown.
How many flowers release pollen?
Peak pollen: The plant has a large number of flowers and one half (50%) or more release pollen.
Fruits One or more fresh fruits are visible on the plant.
How many fresh fruits are present?
Ripe fruits One or more ripe fruits are visible on the plant.
How many fruits are ripe?
Recent fruit drop One or more fresh mature fruits or seeds have dropped or been removed from the plant since your last visit. Do not include obviously immature fruits that have dropped before ripening, such as in a heavy rain or wind.
How many mature fruits have dropped?
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