5TR-Apiary,
What zone are you in, how many deer do you have, and how is your rainfall and soil? That will tell exactly how your black walnuts do.
In Iowa, black walnut is a weed tree. It is a very nice weed tree, but most people put it one notch above red mulberry, silver maple and Honeylocust for tenacity. It is a fast growing hardwood here, but it requires ample water in the early and late spring. It is heat and frost tolerant, and often grows 1â to 2â a year in central Iowa. It is not very drought tolerant when young, but is after about 7 years. It will grow back from the stump, even when you cut down a 15 year old specimen which dominates one side of your garden. Just keep cutting the suckers off, for years it seems.
First, deer and bunnies love to each black walnut whips. Youâll need to fence the trees in if you live in whitetail country. Youâll also need to provide water the first year while the roots get established, but this is standard for any whip planting.
Donât plant near non perennial garden plants. The roots of the black walnut produce a plant toxin called Jungolin or something like that. It is a growth inhibitor. However, certain plants donât care. Iâve successfully grown rhubarb, asparagus and other shade loving plants under the drip line of a black walnut tree, and they thrived.
They start to produce nuts at about 15â tall, or 7 to 8 years. Many black walnuts will produce biennially, with a big flush one year, then a small flush the next. However just as many seem to be annual producers, and early rain is a major factor in how many nuts youâll get.
Black walnut is one of the best âcommercialâ timbers you can grow. In a single lifetime, you can go from whips to valuable harvestable lumber, about 30 to 40 years and 25 mature trees to the acre. The key is to space the trees appropriately and trim the limbs to get yourself a nice, arrow straight 30â long trunk. The commercial value of such a tree is several thousand dollars today. Ancient (100YO+) black walnuts in Iowa commonly top out over 70â tall, and can be worth $10k+ as veneer.