One of my favorite plants in our yard is a large wisteria that wends its way through and around our back deck. Planted in the early 2008 this woody, non-native climbing vine was slow to flower. Although a hardy, fast-growing plant, wisteria usually doesn’t produce flowers until it establishes itself and matures so it was a few years before the first blooms appeared in May of 2011, the image on the left. The center image is from May, 2013 and the image on the right is from the same perspective but in May of 2017.

In early May, before most of the foliage leafs out, the flowers will begin to open, starting at the base and gradually working towards the tip. The 6-12” long drooping racemes of wisteria bloom from basal buds on last year’s growth of wood. It will continue to bloom through the summer when it has full sun and well-drained soil.

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Wisteria vines can become very heavy and need a strong structure such as a trellis, arbor, pergola, or in our case, a deck to provide support. The twining of the stems can be used to identify the species, depending on whether they twine clockwise or counter-clockwise when viewed from above. Our wisteria twines counter-clockwise so it is a Wisteria sinensis, Chinese wisteria. Wisteria that twines clockwise is Wisteria floribunda, Japanese wisteria.

I usually prune it in the early spring when I also give it a low nitrogen-fertilizer. If it sends out unruly new growth during the spring and summer I just break them off by hand. Likewise, with any adventitious shoots that appear at the base of the plant. It’s a low-maintenance plant otherwise with practically no pests or diseases. The bees and other pollinators love it and I saw a hummingbird visiting it this week. One of the few pests that are ever on it are Japanese beetles.

JB

As you can see by the oval white egg on the surface of its green thorax this beetle has been parasitized by a tachinid fly, Istocheta aldrichi. These tiny flies attach a solitary egg to the Japanese beetle. It will hatch a week later and then the tiny larvae will burrow its way into the body to feed. The larvae will consume the beetle from the inside causing its ultimate death, exiting the body to pupate. If you see a Japanese beetle with one of these eggs on it, let it be. It is already on death row and the new fly that it is nourishing will go on to parasitize other beetles in the future.

As I walked past the wisteria earlier this week I noticed bees among its beautiful pendulous violet flowers. I took out my phone to get a picture and as I focused on the buzzing bee I noticed how the individual blooms of wisteria are so like the blossoms of the different beans in the vegetable garden.

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Like bean and pea flowers, the blossoms of wisteria are zygomorphic. ‘Zygomorphic’ means that the flower is only symmetrical when divided along one axis, in this case vertically, unlike the radial symmetry of a flower such as a daisy which is the same on either axis. Clockwise from the top these are the blossoms of a wisteria , a purple sugar snap pea, a pole bean, and a yard-long bean.

Wisteria and beans share many traits with the almost 18,000 other species in the Fabaceae family, also known as Leguminosae, making it the third largest family of flowering plants. Grown world-wide, this group contains trees, shrubs, vines, and herbs that bear fruit called legumes. Many legumes are grown to eat, such as the edible pods of freshly-picked snow and sugar peas and beans, the edible seeds of peas and peanuts, or dried pulses such as lentils, chickpeas, soybeans, beans, and lupin.

I never connected the ornamental lupin, Lupinus polyphyllus, that grow in our flower beds with the salty lupini beans, Lupinus albus, that accompany many antipasto platters. But when you look at the seed pods of an herbaceous lupin the similarity to other legume seed pods becomes apparent. The images are, clockwise from the upper left, wisteria, lupin, purple snow pea, sugar snap peas, and yard-long beans.

Fun fact about another legume: in a method called geocarpy, the seed pods of peanuts develop underground. This gives rise to its other moniker, the groundnut. Post-fertilization, the yellowish-orange peanut bloom sends out a ‘peg’ that grows down to the soil where the ovary at the tip matures into a peanut seed pod.  Like most other legumes, peanuts have nitrogen-fixing bacteria called rhizobia in their root nodules. This capacity to take inert atmospheric nitrogen from the soil means legumes require less nitrogen fertilizer. When the plants die they can improve soil fertility for future crops by releasing that fixed nitrogen.

Scarlet runner beans blossoms

Scarlet runner beans

Any home gardener can benefit from growing legumes, whether they enjoy the beautiful blooms, the healthful benefits derived from eating these high protein and fiber foods or to enrich their garden soil for future plantings.

Susan Pelton

UConn Home & Garden Education Center, 2018

All images by Susan Pelton