Perennial BEANS
Most beans are garden annuals, but a few can be grown as perennials and will produce a prolific harvest each season. Perennial beans, like the Scarlet Runner Beans pictured here, are high in protein. They also have a superpower shared by all legumes; they can improve your soil’s fertility by adding nitrogen.
VarietiEs
Perennial beans come in two main varieties. Scarlet Runner Beans are well suited to temperate regions and yield beautiful purple and black beans encapsulated in vibrant green pods. Hummingbirds love this plant’s bright red flowers. The Asian Winged bean is a warm-weather plant that is less resilient but also beautiful. Each square pod has a fringed wing, and the soft purple flowers attract bees and other pollinators.
WHERE BEANS THRIVE
Regional compatibility
Scarlet Runner Beans are native to North America and thrive in climates where temperatures stay above 10 degrees. Winged Beans hail from Asia and love tropical heat, so they’re sensitive to frost and are typically grown as annuals.
Optimal sOIL & sun
Beans like a well-drained, warm soil that is light or sandy. They do not grow well in acidic soils. If your soil has low pH, you might need to add lime.
Beans require full sun for more than six hours a day to be productive.
RESILIENCE
Scarlet runner beans are an example of a bean that can overwinter in some climates. Winged Beans succumb easily to frost and flooding.
PLANTING
FROM SEEDS
Beans like warm soil and have a hard time germinating when it’s cold and damp. Give your beans a head start by starting them indoors three weeks before the last frost. Plant them in four-inch pots to give the roots room to grow and expand. Two weeks after the first two leaves develop, move them outside. Even better, sow bean seeds directly into the ground to avoid the stress of transplanting. Bean roots are particularly sensitive to being disturbed. Wait until daytime temperatures reach the mid-60s and plant seeds two inches apart, roughly one inch deep.
Best time of year to plant
Plant your perennial beans in late spring, unless you live in a warm, frost-free zone. Then plant in the fall for a winter harvest.
COMPANION PLANTS
Beans make a great companion to most crops because of their nitrogen-fixing powers. They’ll do well if you plant them alongside marigolds, which can help repel the Mexican bean beetle. Do not plant your beans next to onions and garlic, which can prevent bean seeds from germinating.
Growing
Once beans sprout, they’re quick to grow. Vining beans do best with the support of a trellis or fence and can grow more than eight feet tall if you let them. To keep your Winged Beans warm, consider planting them near a patio, house, or a retaining wall that can absorb heat during the day and release it at night.
WATERING
Beans need a lot of water when they start producing flowers and pods, and can suck up about a half-inch a day. During hot summer weather, you may have to water your beans daily once they start blooming.
Weeding
Beans grow fast and tall, so weeds aren’t much of a problem. But a good reason to keep beans weed-free is so slugs can’t hide in them during the day and come out at night to feed on the plant’s low-hanging leaves.
Fertilizing
Legumes are nitrogen fixers, meaning they take care of their own nitrogen needs. As the leaves take nitrogen out of the air, little nodules on the roots put it into the soil, where the plant can draw on it. If you decide to fertilize your beans, use a fertilizer high in phosphorus like guano or bone meal, and feed your plants with potassium by adding kelp meal. Don’t give it more nitrogen or your beans may grow more leaves than beans.
CHALLENGES
Scarlet runner beans are a cinch to grow, but Asian winged beans can be tricky. These tropical plants flower only in places that get fewer than 12 hours of daylight. This makes them hard to grow in most of the United States, where peak summer days run at least 12 hours.
pests & DISEASE
Bean plant leaves are more vulnerable to bugs than their pods. Leafhoppers are tiny, lime-green pests that won’t kill plants but can stress them out, making them susceptible to disease and other pests. Signs you may have a hopper problem are curling leaves that yellow at the tips. Shake your vines to see whether adult leafhoppers start hopping about. If you have an infestation, spray the plant periodically with an insecticidal soap.
Mexican bean beetles are also a threat. Look for copper-colored, hard-shelled insects that eat entire leaves, leaving only the veins. Keep them under control by picking off these pesky beetles when you see them. Aphids like to feed on bean leaves too, and while they won’t kill your plants, they can transmit a mosaic virus that will. Snip off the affected areas and spray plants with insecticidal soap.
While beans might be a little finicky, they don’t have many disease problems, making them a nearly carefree perennial.
Harvest
Once beans start forming, pick them as often as possible to increase yields. If you want slender and tender beans, pick them every three to five days. For dry beans, just leave them on the vine to dry out. Bean flowers are edible so toss them in a summer salad or use them as a garnish.
STORE
Cook with beans the day you pick them because that’s when they taste best. If you do store them, wrap them in a damp paper towel and plastic bag. You can refrigerate your beans for up to a week.
Preserve
Storage beans, or dried beans, are the ones you left on the vine to dry. These beans can be shelled and stored in an airtight container. Soak them overnight before cooking.
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