If you're growing hops to brew your own beer, you may notice silvery or pale green, brittle spikes rising from the crown of the plant or brown spots on the leaves this spring.
"Hop plants have problems with downy mildew, a fungus that attacks plants primarily in April and May," said Shaun Townsend, the hops breeder for Oregon State University.
But don't worry, he added, just cut back the bines (some erroneously call them vines) to the soil with a knife. The plants will start new bines, which will grow quite rapidly. Though wet, foggy weather encourages downy mildew, pruning helps keep the fungus at bay.
Train the bines when they reach 2-3 feet long. You can use braided rope, baling twine or coir, which is woven coconut husk. You can find these items at most home or garden supply stores.
Although one plant reportedly reached 60 feet, Townsend said, gardeners should grow hops on a 15- to 18-foot climbing support, such as a trellis or poles, in a location that receives as much direct sunlight as possible. This combination increases their production of cones — the part of the plant used in beer, he said. The plants can be trained to climb up the south-facing wall of a house, over fences, up pillars or flagpoles, over stone walls or arbors, or along clotheslines. The attractive plant can enhance many landscapes, he said.
"These are big, prolific plants that can cast a lot of shade," he said. "Don't grow them near plants that are shade sensitive, such as a vegetable garden."
The plant will climb energetically on its own, given enough support. The bines always climb in a clockwise direction by wrapping themselves around and gripping the climbing support using short, stiff hairs. Vines, on the other hand, like those of grape vine and sweet pea, climb via the help of tendrils and suckers that cling to the climbing support, Townsend explained.
Be sure to fertilize first-year plants with a multi-purpose fertilizer such as 16-16-16, found at most garden supply stores, Townsend said. Alternate with urea, a form of nitrogen fertilizer available at most garden supply stores, he recommended. Sprinkle a teaspoon of these fertilizers around the base of the plant every two to three weeks from springtime until July to aid root growth, he advised.
Hops, a perennial plant, should be productive for 10-15 years. The plant produces cones every year, which are harvested and dried from mid-August to mid-September, Townsend said. Hops are dioecious, meaning they have separate male and female plants. The female cone contains small glands that produce the essential oils and resins that give beer its aroma and bitterness, Townsend said.
For more information about insect pests and diseases that threaten hops, see OSU Extension's Pacific Northwest Pest Management Handbooks at http://pnwhandbooks.org. To learn more about the history of Oregon's craft brewing movement, explore the Oregon Hops and Brewing Archives from OSU's Special Collections and Archives Research Center at http://scarc.library.oregonstate.edu/ohba.html.