Disease causing pathogens naturally accumulate in plants and the maximum crop yield potential falls as time passes over a period years. Many people rationalize this as the plants are “getting old”. Virus accumulation is an important consideration in long-lived crops like hops. The normal productive years of a commercial hopyard variety that starts with few or no viruses present is about 10 to 12 years before they are typically replaced with newer fresh stock. Initial planting stock that is obtained from old hopyards that are loaded with high levels of viruses will carry this same load and yields are less and plants have to be replaced in fewer seasons. The USDA is aware of this and has a congressional mandate to provide clean seed and planting stock for all commercially important crops. Hops are included in this list and reputable professional propagators source and use this clean nuclear mother stock whenever possible.
Great Lakes Hops (GLH) actively searches for, obtains, maintains, and propagates the cleanest nuclear mother stock available (emphasis on AVAILABLE) to us in our specialized MDOA licensed nursery facility. Most of our nuclear mother stock is sourced directly from the USDA National Clean Plant Program / Facility located in the western USA. This is the only current recognized source of hop propagation stock that has been treated and tested for virus removal and is certified With a VF number at the time of its release. We do not propagate or sell hops or rhizomes as a sideline or as uninspected planting stock. All of our hop transplants are grown specifically for new hop acreage.
However, that being said - read carefully and understand the following.