Common Walnut trees in our area:

 

 

Black Walnut:

 

• Broadleaf deciduous tree, 50-75(125) ft, [15-23(38) m], long trunk, oval to round crown.  Bark dark brown to grayish black, divided by deep, narrow furrows.  Leaves alternate, large pinnate, 30-60 cm long, from 15-23 leaflets (occasionally as few as 11), terminal leaflet frequently missing, each leaflet 5-13 cm long, 2-5 cm wide, ovate-oblong to ovate-lanceolate, acuminate tip, rounded base, irregularly serrate, fragrant when crushed.  Fruit (nut) spherical, glabrous light green (4-5 cm diam.), grainy surface.  Pith of stem uniformly chambered.

 

• Sun.  Prefers deep, rich, moist soils, tolerates drier soils but grows much more slowly.  Extensive taproot and is difficult to transplant.  Wood valuable.  Difficult to garden under since J. nigra inhibits the growth of other plants.  Some plants, however, tolerate this situation, including selected annuals, bulbs, and herbaceous perennials.  Woody plants that can be grown under walnuts include, species of Clematis, Lonicera, Cotoneaster, and Spiraea, as well as Cydonia oblonga (Quince), Ribes sanguinium, and Rosa rugosa.

 

• Hardy to Zone 4     Native from Massachusetts to Florida, west to Minnesota and Texas.

 

 

 

 

 

Common problems with Walnut trees:

 

 

Insects:

 

Aphids			Twospotted Spider Mite
Aphids feed by sucking up plant juices through a food channel in their beaks. At the same time, they inject saliva into the host. Light infestations are usually not harmful to plants, but higher infestations may result in leaf curl, wilting, stunting of shoot growth, and delay in production of flowers and fruit, as well as a general decline in plant vigor. Some aphids are also important vectors of plant diseases, transmitting pathogens in the feeding process. A sticky glaze of honeydew may collect on lower leaves, outdoor furniture, cars, and other objects below aphid feeding sites. Honeydew coated objects soon become covered by one or more brown fungi known as sooty molds. Crusts of sooty mold are unsightly on man-made objects, and they can interfere with photosynthesis in leaves. MORE INFO			The twospotted spider mite prefers the hot, dry weather of the summer and fall months, but may occur anytime during the year. Spider mites feed by penetrating the plant tissue with their mouthparts and are found primarily on the underside of the leaf. All spider mites spin fine strands of webbing on the host plant — hence their name. For detection of spider mites, a 10X to 15X magnifying glass is a necessity. MORE INFO
TREATMENT	TREATMENT	TREATMENT	TREATMENT

 

 

Diseases:

 

Wetwood (slime flux)
Bacterial wetwood, also called slime flux, is a major bole rot of trunk and branches of trees. Slime flux has been attributed to bacterial infection in the inner sapwood and outer heartwood area of the tree. A tree with slime flux is water-soaked and "weeps" from visible wounds and even from healthy looking bark. The "weeping" may be a good thing as it is having a slow, natural draining effect on a bacterium that needs a dark, damp environment. A tree with this bole rot is trying its best to compartmentalize the damage. MORE INFO
TREATMENT	TREATMENT	TREATMENT	TREATMENT