As an amateur I have found this a scary area to unpick, but have been ticking the flowers off one at a time. These plants are part of the leguminous pea family Fabiaceae, which also includes clovers, melilots and rarities like Spiny restharrow and Sainfoin.
Broadly speaking, Vetches include Vicia and Lathyrus with a few odds along the way. I had hoped to give Vetches (mostly Vicia) and Vetchlings (mostly Lathyrus) separate pages until I realised that Bitter-vetch is a Lathyrus and gave up. Such is the world of historic versus scientific naming.
These plants often have tendrils to help them climb, leaflets (divided leaves) and pea flowers in shades of pink, purple, white and yellow (most people are familiar with Broad beans, Vicia faba, Sweet peas, Lathyrus odoratus, and Edible peas, Pisum sativum).
The Captivating Wild Yellow Sweet Pea FlowerThe wild yellow sweet pea flower brings a pop of vibrant color and sweet fragrance to mountain landscapes across the western United States each spring, This hardy wildflower in the pea family has graced high-elevation meadows and forests with its cheerful display for ages, Let’s take a closer look at the allure of this mountain jewel
Where to Find the Wild Yellow Sweet Pea
Also called yellow pea or mountain thermopsis, this radiant wildflower goes by the scientific name Thermopsis montana. It inhabits higher elevations across mountain states from New Mexico to Montana.
In spring yellow peas bring their golden hue to shady, moist canyons and forests. Look for them gracing streambanks mountain meadows, and woodland understories at elevations between 5,000 to 11,000 feet.
Some top spots to view wild yellow sweet peas include trails in:
- The Rocky Mountains
- Ranges of Colorado, Utah, and New Mexico
- The Wasatch Range of northern Utah
- The Cascade Range of Oregon and Washington
- The Bitterroot Mountains of Idaho and Montana
Identifying the Yellow Sweet Pea WildflowerThe yellow sweet pea flower is easy to identify by its vibrant color. fragrance foliage and form
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Flowers emerge in upright clusters containing multiple rows of half-inch blooms with five fused petals in an elegant banner shape.
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Leaves are compound with three oval leaflets joined at the base of a central stem. Leaflets can reach up to 3 inches long.
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Stems stand 1-3 feet tall, are rigid, and lined with pointed green bracts. Flower weight causes stems to gently arc downward.
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Seed pods are long, thin, upright, and covered in fine hairs. They contain the plant’s small brown peas.
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Flowers emit a lovely, sweet pea scent.
When Yellow Sweet Peas Bloom
One of the earliest wildflowers to emerge in mountain areas, yellow sweet peas start blooming in May at lower elevations and early June at higher ones.
Their peak flowering season runs from late May to July. Occasional plants may still sport bright blossoms into August.
Blooms open progressively from the base of the flower spike upward over weeks. Each flower only lasts a few days, but the ongoing show continues for a month or more.
Growing Conditions for Yellow Sweet Peas
Yellow sweet peas thrive in partly shaded mountain habitat with indirect sunlight filtering through aspen, spruce, or pine forests. The dappled shade protects the moisture-loving plants.
Although they tolerate drier conditions, yellow peas flourish along streams, seeps, and wet meadows. Rich, organic soil and ample moisture help them thrive.
Their thick taproots and rhizomes allow them to overwinter beneath the snow. As soon as the ground thaws and warms a bit in spring, they send up erect shoots topped by emerging flower buds.
Companion Plants and Wildlife Value
Wild yellow sweet peas mingle beautifully in mountain communities with lupines, paintbrushes, arnica, columbine, fireweed, and larkspur.
Their flowers draw buzzing bees, flies, and butterflies. Seeds provide forage for finches and chipmunks. Deer may nibble foliage.
Growing Yellow Sweet Peas at Home
If you live in the sweet pea’s native range, transplant small plants to recreate a patch in your mountain garden. Select a site with afternoon shade and humus-rich soil. Keep plants evenly moist.
You can also sow fresh wild-collected seeds in fall. Cold winter stratification aids germination.
Gardeners elsewhere can grow the hardy Thermopsis villosa from seed. It has similar bright yellow flowers on 2 foot stalks blooming in late spring.
The Allure of the Wild Yellow Sweet Pea
With its vibrant blooms and sweet scent perfuming mountain forests, it’s easy to see why the yellow sweet pea flower is a beloved sign of spring out west. Watch for its luminous beauty brightening hikes and roadsides.
Wild Yellow Sweet Pea Facts
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The wild yellow sweet pea is known scientifically as Thermopsis montana.
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It grows at elevations between 5,000-11,000 feet in mountainous areas of the western United States.
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The bright yellow flowers bloom from late May through July.
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Plants reach 1-3 feet tall and thrive in partly shaded, moist habitat.
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The sweet pea is toxic if ingested and should not be eaten.
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Gardeners can grow the related Thermopsis villosa from seed.
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This wildflower provides nectar for pollinators and seeds for birds and small mammals.
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Yellow sweet peas spread slowly via rhizomes and are not invasive.
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They are cold hardy to zone 3 and can tolerate cold mountain winters.
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The sweet scent and golden color make this a favorite spring wildflower out west.
Fodder vetch – Vicia villosa
I had initially identified this legume as Tufted vetch in a field on the outskirts of Seaford. But as I write this page, I am noticing that the flowers are broader and more blousy-looking than tufted vetch and have white tips. I’m therefore assigning it as Fodder vetch, which is consistent with the presence of Sainfoin and the idea that this field has been sown by the farmer with a pollen rich wildflower mix.
Common vetch – Vicia sativa
Common vetch is larger and more substantial looking than the flowers talked about above. Its height was 30cm plus and leaflets being about one centimetre across and a few centimetres long. The flowers were 1cm to 2cm across, which is larger than everything listed already on this page. Although not easy to spot in the pic, it does have tendrils (disappearing out of shot top left).
I identified it as Vicia sativa due to the following features: one to three pink flowers in the leaf joint; the leaflets have a needle point; the leaflets halfway along the stem are larger than the ones nearer the top or bottom. The last two features mentioned separate it in theory from Bush vetch, Vicia sepium which I have yet to photograph.
The photo below was taken while on holiday at Rye Harbour.
How to grow sweet peas: tips from a sweet pea flower farmer
FAQ
Can you eat wild sweet pea flowers?
While opinions vary on the edibility of Wild Sweet Peas, those who have sampled the plant describe its flowers and young tendrils as having a sweet, grassy, vegetal flavor.
What is the wildflower that looks like a sweet pea?
Tufted Vetch Plants (Vicia cracca) Sprawling perennial plant with masses of small pea-like purple flowers, the sweet pea of the meadow. This really is the centrepiece to any meadow with its showy blue-purple to pinkish-purple flowers.
Is wild sweet pea invasive?
Perennial sweet pea reproduces by seed but persists and spreads locally mostly by rhizomes (underground), making it difficult to control once established.
What is another name for a wild sweet pea?
Lathyrus vestitus. Lathyrus vestitus, commonly called Wild Sweet Pea, is a member of the Fabaceae (pea family).
What is a wild sweet pea plant?
Wild Sweet Pea Plant Identification. The wild sweet pea vine (Lathyrus latifolius) grows to a height of 7 feet. Small racemes of pink flowers appear on the vine from spring to fall and are followed by seed pods. Native to central and southern Europe, the plant has also spread to North Africa.
Where can I find wild sweet pea?
Wild Sweet Pea can be found in chaparral and Oak woodlands at elevations ranging from sea level to 1,500 meters. I saw these specimens in Upper Sycamore Canyon. The leaves of this plant are quite similar to Spring Vetch (Vicia americana).
What does a sweet pea look like?
The sweet pea, a herbaceous perennial, sports lance-shaped foliage that flank the stems and petioles. The plant produces racemes of 4 to 14 flowers on the top of each stem. The flowers appear either pink with a purplish hue or white in color. Each flower measures up to 1 inch across.
When does a sweet pea flower?
Sweet pea flowering time depends on your climate. These plants prefer cooler temperatures and will start to fade in high heat. Areas with cooler summer temperatures can expect flowers in late spring (May or June) or fall (September or October). Warmer regions can expect flowers in winter and spring. Sweet pea plants are light-sensitive.
Which sweet pea plants are fragrant?
Cultivars of sweet pea plants (Lathyrus odoratus) include: ‘Old fashioned’: Sweet peas labeled old fashioned should be fragrant. Spencer cultivars: These are exceptionally hardy vines with striking coloring, but not all of them are particularly fragrant. ‘Bijou Group’: This is a sweetly scented dwarf variety for containers.
How tall does a sweet pea vine grow?
The wild sweet pea vine (Lathyrus latifolius) grows to a height of 7 feet. The sweet pea, a herbaceous perennial, sports lance-shaped foliage that flank the stems and petioles. The plant produces racemes of 4 to 14 flowers on the top of each stem. The flowers appear either pink with a purplish hue or white in color.