Golden Pea or Mountain Golden Banner, A Long Blooming Native LupineDonna L. Long

flowering stalk of Golden Pea (Thermopsis montana) — Flowering stalk of Golden Pea (Thermopsis montana) in my garden.

Golden Pea, (Thermopsis montana), is a member of Fabaceae (Legume/Pea) Family. It’s also called, “Mountain Golden Banner or False Lupine”. I refer to the plant as “Golden Pea”. To me that name says more about the plant. I know from this name that the flower is yellow and that the plant is in the Pea family and most likely a nitrogen fixer. I’ll refer to it as Golden Pea for the rest of this post.

One of My First “Babies”

This is one of the first native plants I bought over twenty years ago. I purchased it along with Baptisia australis at Bowman’s Hill Wildflower Preserve in Bucks County, Pa.

This flower comes back each year in a dry area along the fence in my garden. This year it sent up one flower spike about 4 feet tall. There is another much shorter spike growing in the cluster of leaves at the base of the plant, with no sign of a flowering stalk.

This plant seem to be not so well-known gem of a native plant for the garden. I had a hard time finding information about it.

Golden yellow blossoms of Golden Pea (Thermopsis montana) blossoms

Pretty Yellow Blossoms

The flowers begin flowering at the bottom of the flower stalk. Each day more of the blossoms open until the last blossom opens on the tip of the flower stalk.

If a plant’s blossoms have the distinctive pea family flower shape with banner, wings, and keel, it classified as in the Pea (Fabaceae) family.

The plant blooms in late May to June. How long does it bloom? I really don’t know. I haven’t paid much attention to it over the years. I don’t know why. But, I’ve decided to pay more attention to the more unassuming plants growing in my garden.

This isn’t the easiest plant to find growing information on. The USDA Plants Database came to the rescue again.

A Western Native

The flower stalk resembles a yellow lupine. Lupine perennis is the pink and purple flower seen along the highways of Maine. Which is not a native but indigenous to the western areas of North America. Lupine perennis has become invasive in Maine.

The lupines of cottage garden fame are Lupines polyphyllus, Russell hybrids. These are the most common and widely known lupines. The Russell hybrids are also indigenous to western North America.

Golden Pea, Thermopsis montana, is also a native of the western areas of the country. I haven’t come across anything that said Thermopsis montana was invasive in my area. I didn’t know it was a western native when I bought it. But it hasn’t spread beyond my backyard.

Growing the Golden Pea

We haven’t had rain for perhaps a month, but this plant seem not to be bothered by the dry conditions. What I can find out about this plant is that’s native habitats include dry grassy plains in the western mountains. And it likes moist areas, too.

The flowers are followed by velvety brown pods if the stalk is not cut down (deadheaded) after flowering.

Like many legumes, I assume the plant has a taproot that doesn’t like to be disturbed. Dividing this plant would be a bad idea. I would just dig up the part of the plant I didn’t want and compost the unwanted pieces.

Southern Pea tolerates low-fertility soil and drought. My Golden Pea is in a dry spot and seems to like it. It hasn’t spread.

Caution

Plants of the Pea family range from edible to poisonous. If you have children who visit your garden, you may want to proceed with caution growing this plant.

In the Garden

I bet Golden Pea would look spectacular paired with the pretty purple of Baptisia australis. But in my garden the plants are on opposite sides of the yard. And neither plant like to be moved.

The only local gardening information I can find is for Thermopsis caroliniana, Southern Lupine. The plants look similar, with Southern Lupine having numerous stalks topped with numerous flowers. Unlike the single tall flower stalk of the Golden Pea. Southern Lupine is indigenous to the east, but the growth habit is over numerous yellow, pea-like flowers instead of one tall flower spike.

Baptisia tinctoria vines of yellow blossoms.

Baptisia tinctoria’s yellow blossoms.

Another eastern native is Baptisia tinctoria which I found growing in Houston Meadow, in the Wissahickon Valley Park here in Philadelphia back in 2010.

I checked my copy of Tracy DiSabato-Aust’s, The Well-Tended Perennial Garden: Planting & Pruning Techniques, on caring for Golden Pea.

Of course it wasn’t listed. But I did find information on the Lupinus hybrids which are the common Russell lupine hybrids. DiSabato-Aust says that deadheading will prolong the bloom and help prevent seeding. Russell lupines can be invasive in some regions. After initial flowering she suggests cutting down the stalks about six inches or to the basal leaves at the base of the plant.

She says cutting back is an effective control against aphids which seem to trouble Russell hybrids. I don’t see any aphids on my plants.

Maybe I’ll do that next year. Maybe I’ll pay more attention to it next year. Am I a bad “plant mommy”?

Golden Pea In the Ecosystem

Golden Pea attracts bumblebees.

Would I plant this plant again?

Now I know this plant is not indigenous to my area, would I plant it again? Maybe. It is a pretty plant. It has a neat, stay-put clumping habit. It’s no trouble. I’ve never seen aphids on it. I haven’t read that it a nuisance or invasive in my area. So maybe.

How do you feel about planting indigenous plants that are native to your country, just not to your region?