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Crop Matrix Tool

Use this tool to find out about characteristics; such as soil pH, cultivation methods, pests and post harvest treatment; for a specific crop. To load a crop's characteristics choose a crop from the drop-down menu. To see a list of all possible crops grouped by category click on the “Show List of All Available Crops” link next to the drop-down menu.

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Black Walnut

Common NameBlack Walnut
Latin NameJuglans nigra
Visual Traits
Floweryellow-green, monoecious, late May-early June at leaf-out
Foliage/Fall leaf colorgolden yellow, early to mid-September
Fruit / Nutfruit ripens Sep-Oct; persistent through leaf fall
Other valued traitsfine furniture
Cultivation and Mulchingrequires weed management 2-3y
Field spacing / planting depth50x50ft spacing optimal for nut production
Graftinginlay graft
Pollinationflowers of both sexes do not usually mature simultaneously on single tree; may set self-fertilzed seeds
Propagation methodseed, grafting and budding, container
Pruningprune lateral branches, early spring; sprouts after disturbance; some bole sprouting in response to release; nut v. timber production objectives define different tree forms and pruning practice
Seed treatment and storagecold stratification 90-120days
Seedling treatmentseedlings smaller than 3/16in caliper (at 1
Sowing seedgerminates early spring during first or second season
Transplantmachine or hand
Insect and invertebrate pestswalnut caterpillar (Datana integerrima), fall webworm (Hyphantria cunea), ambrosia beetle (Xylosandrus germanus), flatheaded apple tree borer (Chrysobothris femorata), walnut curculio (Conotrachelus retentus), walnut shoot moth (Acrobasis demotella)
Pathogensfungi: (Phytophthora citricola) and (Cylindrocladium spp.), walnut anthracnose (Gnomonia leptostyla), (Cristulariella pryamidalis), (Mycosphaerella juglandis), and (Nectria gallegena)
Toxicityjuglone concentrated in roots and nut husks inhibits associated vegetation
Compaction (tolerance)intermediate
Fertility / qualityrich, fertile
Mineralsassociated with limestone
Moisture and drainagedeep, moist, well-drained; suppressed on dry ridge sites; moderately flood tolerant
Salt toleranceintolerant
Soils and topographycoves, well-drained bottomlands; alluvial soils
Textureprefers sandy loam to silty loams, silty clay loams
Growth Pattern
Good seed crop interval (fruit load)twice in 5y; flowering habit may be strongly influenced through cultural practices like pruning, irrigation, and pest control
Growth ratefast, surpasses oaks
Root habittaproot or strong lateral roots, depending on soil
Seed-bearing age /max production10y / 30y
Habitat and Climate
Exposureperforms best on lower north or east-facing slopes
Fire tolerancereadily sprouts following disturbance
Frost-free days (FFD)170
Growing degree days (GDD)140-280
Hardiness ZoneZones 4-9
Native RangeCentral and Eastern United States, Southeastern Canada
Rainfall / humidity35in
Wind / ice / frost susceptibilitysusceptible to early fall and late spring frosts
Light recommendationfull sun, woodland edges
Shade toleranceintolerant, esp at pole stage
Vegetation Associations
Competitive abilitymust be dominant or codominant; allelopathic; responds well to release of at least 3/4 of crown
Indicator species and associated forestmixed mesophytic