Hops

Traveling in Germany a few years ago, I was a little confused by grids of 20-foot poles pointing skyward. They looked alien, like a giant, bristling growth. That was before I learned about hops.

Hops are flowers from the Humulus lupulus plant and they love to grow up!

Hop flower (LuckyStar) CC BY 2.5

Hops in beer

I do not know how to make beer, so my knowledge in this area is limited. [Brewers, feel free to add better information in the Comments!] I do know that hops have been used in beer-making since the 9th century. Before that, other flowers and bitter herbs were used, including dandelion, marigold, horehound, and burdock root, in a mash called gruit. One of the main reason brewers switched to using hops was because there was a tax on gruit, but no tax on hops. Of course, that situation was only temporary. Hops are said to have an antibacterial effect, as well as providing a bitterness that balances malt’s sweetness. It is the unfertilized female flowers that are used in beer-making. The acids in beer have sedative properties, with or without alcohol.

Hops varieties

The flavor and aroma of hops flowers is largely the result of where they are grown. While there are many different hops cultivars, the plants can be [overly] simplified into three different types: American, British, and Continental European. American hops are robust, heavy producers with long sidearms. They tolerate a wider range of soil pH and soil structures. American hops are generally planted 4 feet apart in rows that are 14 feet apart. Common American varieties include Willamette, Chinook, Brewers Gold, and Zeus. British and Continental European varieties are genetically different from the American varieties. They have smaller, finer root systems and are less tolerant of soil variations. These varieties have shorter sidearms and can be grown 3 feet apart in 12-foot rows. This allows for more plant density on the same acreage. British varieties prefer more alkaline soil (pH 6.5 or higher) and can tolerate heavier soils. Common British varieties include Viking, Fuggie, and Challenger. Continental European varieties, such as Magnum, Glacier, and Pearle, prefer more acidic soil (pH 5.5 to 6.2). One subset of the European hops, referred to as noble hops, are less bitter, with a stronger aroma than others. These hops are used to make Pilsners and other mild beers.

Hops plant structure

Hops flowers are green, soft-petalled seed cones, also known as strobiles. Hops plants are dioecious, which means the plants are either male or female. To prevent male pollen from fertilizing the female flowers, plants are propagated vegetatively. When hops plants are grown from seed, the males are culled as soon as they are seen, similar to other flower bud crops. The hops vine is called a bine. As the bine wraps around a support, side branches, called sidearms, emerge. At the end of the growing season, everything aboveground dies back. In spring, the roots put out new bines and the whole process begins again.

How hops grow

Hops plants are fast growing, perennial climbers. That’s what all those poles and strings were - hopfields or hop yards. Hops grow from rhizomes that are placed in ‘hills’ or mounds that are 6 to 12 inches high. This helps with drainage. The rhizomes are placed 4 inches below the soil surface. Commercially produced hops are generally started in pots, in March. Then they grow in greenhouses until July. Plants are placed 7 to 8 feet apart in a grid formation that matches a series of poles that support strings used by the hops plants to climb toward the sun. In these commercial fields, air flow is critical to disease and pest management, so the bottom 3 feet of foliage is removed. If you are growing just a few plants for yourself, you don’t need to do that.

Early season hops yard (Williamborg) Public Domain

Mature hop yard (Marti) CC BY-SA 3.0

Hops prefer very specific conditions, requiring moist, temperate regions with plenty of boron in the soil. Most of the world’s hops production occurs along the 48th parallel north, which includes Germany, China, and Poland. Hops grow well in the same conditions preferred by potatoes, making Idaho, eastern Washington, and parts of California and Oregon good hops growing country. One acre can produce 2,000 to 3,000 pounds of mature hops flowers, on average.

You do not need to install 20-foot telephone-style poles in your yard to grow hops. One neighbor of mine simply attached strings from a fence to the roof of his house. Each spring, the bines emerge and lovely green flowers appear in late summer, shading the sunny side of his house! You can also grow hops using a tee-pee of bamboo poles, just to see what it’s like.

Pests and diseases of hops

Powdery mildew and downy mildews can be particularly troublesome. Mites and weeds become more problematic as interior sunlight and air flow increase.

Hops are toxic to dogs, so do not grow hops in areas frequented by Fido. You can, however, eat the young bines the same way you would eat asparagus.