Growing food-producing plants alongside native plants is a popular gardening practice. One flowering plant that is indigenous to several regions is lupine. Not only will it attract pollinators who help food production, but it also fixes nitrogen in your garden’s soil.
Table of Contents
Lupine is a North American favorite. Texas calls one species its state plant. In the eastern part of the country, L. perennis is a common hybrid that grows wild on dunes, open forest floors, and savannahs in the Pacific Northwest. Another, L. polyphyllus (also hybrid) grows in colder regions of Canada and the western US. These are proof that lupines thrive anywhere in the North American continent.
What’s unmistakable about all lupines is their palm-like leaves and colorful spikes of whorled flowers that bloom in spring. In March through May, I like to stop at a hillside where Texas bluebonnet congregates. The sight and smell of an entire hill covered in Texas bluebonnet is truly breathtaking. I have no doubt other lupine species provide similar visual stimuli in North America and Europe alike.
Whether you grow hybrids (like Lupinus polyphyllus), or a certain flower color there is much to choose when it comes to lupines. There are tall and dwarf varieties. Spikes bloom in yellow, blue, pink, and purple. Fill your garden with tall yellow or pink hybrids that bloom year after year, or try hybrids indigenous to the western United States in different colors.
- PyGanic Botanical InsecticideNeem Bliss 100% Cold Pressed Neem OilSafer Brand Insect Killing SoapSouthern Ag Liquid Copper Fungicide
Quick Care Guide
All About Lupine
Here, we’ll focus on Lupinus species that are indigenous to North America. The Latin word, Lupinus means wolf, based on the previously held belief that lupines wolf the soil they’re in. Not so, however. They don’t wolf the soil, but because they are related to pea plants, they provide nitrogen.
The four specific plants we’ll cover here are known by their Latin names as Lupinus polyphyllus, Lupinus perennis, Lupinus arboreus, and Lupinus texensis. These are called lupines, lupins, and Lupinus texensis is commonly known as Texas Bluebonnet.
Lupines are perennial. Especially if you plant a lupine native to your area, you’ll be able to enjoy them every vernal season. Lupines have palmately divided leaves that lie low to the ground. Lupine flowers are whorled spikes of 1 to 2 centimeter-long blooms with colors ranging from deep blue to yellow. Some varieties have white markings on flowers. When spring flowers die, a fuzzy seed pod emerges to spread the lupine seed for next spring. Each pod contains about 12 seeds. None of the plant is edible for humans, and seeds are especially toxic.
Lupines reach anywhere from 1 foot tall to 7 feet tall and at least 1 foot to 1.5 feet wide. In your perennial garden, they will spread easily. A large patch of lupine attracts native and hive bees to your garden, who help pollinate food crops. Hummingbirds and butterflies flock to lupines too. They’re a great plant to introduce into a succession garden, providing nitrogen content to your soil.
Cultivate lupine in a garden bed, a container, or in a grow bag. When growing in a container you can experiment with different light situations. You can also bring lupine in during winter to keep the root structure safe and intact. You must keep them in check in a container, however, because they’ll quickly become root bound if they’re left to continuously reproduce for too long.
Types of Lupine
There are too many lupine species out there to cover all of them here. So, we’ll discuss a few different species.
Lupinus polyphyllus, is a hybrid also known as large-leaved lupine or Russell lupine. It grows in the western US, and from Southern Alaska to British Columbia, east to Quebec. There are several variations of Russell L. polyphyllus. Chances are you’ll find a characteristic lupine in the area you live. Russell flower colors vary greatly. Some are deep blue or purple, and some are white and fuschia. Dwarf cultivars like Minarette exist here too.
Lupinus perennis, or wild lupine, is specific to the eastern North America coast, from Texas up to Labrador. Unlike other lupine species, L. perennis flower spikes are sparse rather than compact. Most cultivars have a blue and white flower. Some are white, purple, or pink. Wild lupine is important for many different lepidoptera species. In fact, this lupine hosts caterpillars of the endangered Karner blue butterfly — a great pick for east coast folks.
Lupinus arboreus, or tree lupin is an interesting species of the genus Lupinus. It grows up to 7 feet tall, and is indigenous to Northern California, growing on sand dunes and alongside coastal sage scrub. Flowers are sparse and either yellow or purple. Because it is so prolific, either via human interaction or pollination it made its way down the coast to southern areas of California where it is considered invasive.
Lupinus texensis, or Texas Bluebonnet, is the most popular lupine in the southern US. Its distribution ranges as far west as Texas and spans through Oklahoma, Louisiana, and Florida. It is considered one of the most important plants that support native bee species. Bluebonnets are called so because they are deeply blue, with white spots. If you have a chance to visit a bluebonnet field in the spring, you might even be able to find a white albino bluebonnet among the others. These grow to reach about two feet tall.
One really cool variety of this pea-related plant is the Russell Hybrid Mixed Colors. It blooms in all the colors we’ve mentioned here in one seed pack!
Care
Grown in the right conditions, lupines flourish and thrive. Let’s cover the tools you need to grow lovely tall hybrids in yellow, pink, purple, or blue.
Light & Temperature
Lupines prefer full sun. They grow in USDA hardiness zones 3 through 8. Some botanical varieties handle cold temperatures below 32 degrees Fahrenheit, and all thrive in temperatures below 86 degrees. Outside of those ranges, they may experience foliar and floral damage.
If you’d like to enjoy flowers a little longer, bring in your lupines. Since they’re perennial, you can let nature take its course. Flowers and leaves die in summer naturally. As long as the roots are healthy lupines bloom again in spring.
Water & Humidity
Lupines need about one inch of water per week. However, many are drought tolerant and don’t need water once established. Keep the soil moist, but not wet. Depending on the variety you may not even need to water unless there’s a drought. Irrigate lupines via soaker hoses or drip irrigation in the morning. Do not wet the foliage, as this causes mildew.
Soil
Lupines love acidic, sandy, well-draining soil. Endemic or native species don’t need any extra fertilizer. They’re already suited to their region. Those in pots or grow bags can live in potting soil amended with peat moss, which lowers the pH. The typical pH range is 6.5 to 7.5. For some in the lupin genus, add coarse sand to the soil for extra drainage. Check your local agricultural extension office for more resources about growing indigenous lupines.
Fertilizer
Most lupines don’t need heavily fertilized soils. Provided that you’ve found sources for plants indigenous to your region, you won’t have to do much. If your soil is too alkaline at the start, amend to acidify it slightly.
Propagation
All the tools you need to propagate are contained within lupine. Use either seeds or cuttings to have annual blooms all over your garden. You can also let lupines self-spread by seed.
To propagate plants by cutting, use a sharp knife to separate out a section of your lupine right at the base (or at the top of the crown) in early summer or late spring. Section all parts of the basal cutting, and dip them in root hormone. Put them directly in the soil they’ll be housed in, and keep them moist. In about a week, your plant cuttings will root.
To propagate by seeds, collect seed pods from mature plants. Place them in a paper bag in a warm dry place and wait for them to pop open. Then take the seeds and scarify them with sandpaper or a small knife. Soak the seeds overnight to break down the seed coat, and place them in a refrigerator for at least one week. Then plant them in an appropriate growing medium. You can let mother nature do her thing, by preparing the seeds and planting them outdoors in the fall for cold stratification. In indoor propagation, lupine sprouts in about three weeks.
Pruning
Prune off spent flowers to promote more blooms. Prune them to the surface of the earth in late summer as they die away, but make sure to leave a flower stalk with a seed pod so the plant can spread on its own if you want it to renew itself. Take stem cuttings for propagation at this time too.
Some gardens benefit from lupine control to prevent too much annual spread. Wait until they flower, and prune them down to the ground before the seed pod forms. Use flower spikes in floral arrangements. To prepare lupines for winter, cut them down in fall and cover them with a loose, light mulch like pine needles, or hay.
Troubleshooting
Plants that are indigenous to regions of North America will not have many problems in their habitat. However, remember this when working with these pea family members.
Growing Problems
Too much spread can occur. Lupines will take over gardens in a matter of two years. To prevent overrun gardens, harvest flower spikes as they bloom. To control spread collect seeds in their pods after flowers die. Give them to friends who also want to grow lupines, or propagate them on your own. Avoid growing the yellow tree variety of lupine in southern California, as it is considered invasive.
Pests
Lupin root weevil feeds on the roots of lupines. They’re numerous in areas of Europe and Washington. Fully-grown beetles lay eggs on the soil. Eggs hatch and grubs burrow below to feed on lupine root material. Damaged lupine taproots devastate a plant. Most gardeners use pyrethrins to combat this pest before they are full-grown and become more numerous.
Aphids are generalist pests that feed on all varieties of lupin. Use all the resources you have previously used to remove them. You’ll find them around the base of your lupines or on the undersides of leaves. A blast of water from a hose will keep them from feeding any longer. If an infestation gets out of hand, try neem oil or insecticidal soap.
Diseases
Anthracnose is a disease caused by the fungus Colletotrichum gloeosporioides. Infected leaves darken around the edges and begin to necrode. The fungus continues to grow if left alone and overwinters in soils. To prevent further leaf blight, use a copper fungicide spray. If this doesn’t work, remove and dispose of affected plants.
Powdery mildew occurs in an overly wet spring or fall. If you catch it early, simply remove the damaged leaves and monitor the plant going forward. Neem oil or copper fungicide are also effective.
Overly wet soil causes root rot in lupines. Keep irrigation to 1 inch per week. If your garden has taken on a lot of precipitation, cut back on watering. For pots, make sure to incorporate coarse sand into your planting medium.
Frequently Asked Questions
Q: Do lupins like sun or shade?
A: Sun, sun, and more sun is what these popular plants need to grow.
Q: Do lupine plants spread?
A: Yes. Some that made their way outside their region are considered invasive in parts of North American, Europe, and the Islands of the Pacific.
Q: Do lupins come back every year?
A: They return in spring annually for multiple years in a row.
Q: Is lupine toxic to dogs?
A: Yes. Although lupine is related to the botanical pea, it is toxic to dogs and humans alike. If you’re worried about exposing pets to lupine flowers, keep this plant out of their way.
