Black walnuts (Juglans nigra), also known as Eastern walnuts, are native from Massachusetts to Florida, and as far west as Minnesota and Texas. These trees grow wild in Connecticut and thrive in the state's cold-winter, mild-summer climate. The state is defined as Zones 5 and 6 on the U.S. Department of Agriculture Plant Hardiness Map and temperatures can drop to minus 20 degrees F in winter.
Trees can grow to 150 feet in the wild, but are usually smaller in landscapes. Walnut trees have dense foliage and are good shade trees. There are many cultivars of Eastern black walnuts, and each produces a nut that is slightly different. All black walnut trees should be planted in full sun and require regular water.
The Burns cultivar originated in Ontario and is best known for bearing nuts with a thin, easy-to-crack shell. Connecticut's climate is suitable for the Burns cultivar. Nuts can usually be cracked on the first try and the kernel may be removed as two halves.
This cultivar is thought by many to have the best-tasting nut of all black walnut trees. Originally from Iowa, the nut of the Mintle black walnut is small, but the kernel consistently fills the shell. Nuts are moderately difficult to open, and may be stored for up to two years without going bad.
Mintle trees are susceptible to anthracnose leaf spot, and tend to bear nuts in alternate years. Nuts should be ready for harvest in early September in Connecticut.
This heirloom cultivar was first discovered in Pennsylvania in 1881. The nuts have thin shells that usually can be cracked on the first try, and kernels come out as halves. Nuts are flavorful, though may not fill completely if the winter is mild.
These trees are fairly resistant to anthracnose leaf spot and nuts ripen in late September to early October.
This cultivar is originally from Pennsylvania, but does well in Connecticut's climate. The Vandersloot walnut is large and tasty, and is in a medium-thin shell, making it fairly easy to crack. This tree, unlike many other black walnut cultivars, is resistant to anthracnose leaf spot.