The hop (Humulus lupulus) is a hardy, perennial plant that produces annual vine looking bines from a permanent rootstock (crown). Vines may grow up to 25 feet in a single season, but will die back to the crown each fall. In addition to the true roots and aerial bine, the crown also produces underground stems called rhizomes. Rhizomes resemble roots but possess numerous buds and are used for vegetative propagation. Thus propagated, all plants of a given variety are genetically identical.
Hops are dioecious, which means they have separate male and female plants. Only the female produces the flowers that are used for brewing or medicinal purposes. Male plants have no commercial value only used to pollinate females. Because brewers prefer seedless hops, males are only grown with otherwise poor yielding female varieties.
Hops are native to the temperate zones of the Northern Hemisphere. They are found wild in Western Europe, Asia and certain parts of North America. Hops are being grown in Canadian provinces and as far south as the Carolinas, therefore the ability to grow hops is usually not limited by location. The health of the vine is more dependent on the grower’s ability to provide proper growing conditions and care. Under good conditions, a mature hop plant will produce ½ – 2 pounds of dried flowers per plant, and will be a joy to grow and utilize.
Being a perennial plant, the hop lays dormant during winter and is rather unaffected by freezing temperatures, having survived the past two winter Polar Vortex conditions experienced in our region quite well. When the annual bines break ground, flowering and die back is very much determined by local temperature and day length. The bines will not break ground until soil temperatures have rose to the point where most spring flowers appear. A minimum of 120 frost-free days are required for the hop to fully ripen a crop of flowers. Once out of the ground, the vines need to be supported off of the ground.
Vegetative growth continues until approximately mid-July when most hops are either past bloom or in full bloom (depending upon location and variety). At this “burr” stage, the flower is approximately ¼ inch in diameter and is composed of many florets whose styles give it a spiny appearance. In Ohio most female flowers develop in June and July and mature and ripen between early August and mid-September, depending on location and variety. After the flowers ripen, the vine will continue to build reserves until it totally dies back with the first freezes of fall.
Because hops can produce such a large vine in a matter of months, they will use a large amount of solar energy, water and nutrients. This is not to say that the hop will not grow under less than optimum conditions, only that the vines will be smaller. Hops prefer full sun and rich soil, well drained with a pH of 6.0-7.0. If drainage is a problem, raised beds can be built using surrounding top soil mixed with organic matter.
Because the hop is a perennial, it’s not a bad idea to dig holes about one foot deep so that some manure and other slow release organic fertilizers can be mixed with your soil and replaced into the hole. This puts the nutrients in the root zone.
Upon obtaining the rhizomes, they should be stored in a plastic bag slightly moistened in a refrigerator. Rhizomes should be planted vertically with the bud pointing up or horizontally about 1” below the soil surface. First year hops have minimal root system and require frequent short watering much like any baby plant, but do not drown it with too much water. Once the hop is established after the first season, less frequent deep watering is best, preferably drip irrigation. Don’t expect very much in growth or flowers the first year as the hop is basically establishing its root system. Full growth and maximum crops of flowers will be achieved during the third season.
If you are interested in learning more about the hop and malting barley research that is being conducted by the Ohio State University, there are several upcoming educational opportunities. We are holding our first Friday Hop yard tour in wooster and Piketon on the first Friday of October. Registration is required for both events. Interested parties must register by calling McGlothin at 740-289-2071, ext. 132, or by emailing her at firstname.lastname@example.org. You can also visit our Ohio Hops Facebook page or the OSU South Centers website for more information. If you would like to be added to the Ohio Hops email list to receive Ohio hop updates and information contact Brad Bergefurd, Bergefurd.email@example.com or call the OSU South Centers 1-800-860-7232 or 740-289-2071 extension #132.