Lupine Flower (Lupinus): Types, How To Grow, And Plant Care

Lupines are beautiful plants that introduce plenty of color and life into any garden. They are easy to grow, and don’t need a lot of care, making them a popular choice in many spaces.

There are about 200 different species to choose from, the majority of which come from North and South America, but you can also find some species in the Mediterranean and North Africa, too.

Lupines are grown across the world, not only for their towers of flowers, but also because they fix nitrogen into the soil.

Not sure if lupines are for you? Let’s take a look at what you need to know.

At A Glance: What You Should Know About Lupins

Lupines, or lupins, come from the pea plant family, Fabaceae, and you can see the resemblance in the shape of the flowers. You may also know them as bluebonnets, too.

Most are herbaceous perennials that can reach between 1 and 5 feet tall, while others are annuals, and some are even shrubs, which can reach a maximum of 10 feet tall.

The flowers of a lupine plant are instantly recognizable, produced on upright flower spikes, either in dense or open whorls. 

Some plants are bicolored, featuring two different colors on different parts of the petals. Some are even tricolored, as the buds emerge in different colors than the mature flowers.

The foliage is pretty distinctive, too, with leaves that fan outward from a single growth point, either in a bright or silvery green.

They will tolerate a range of temperatures and conditions, especially when you choose different species, and they grow particularly well in USDA zones 4 through 8.

Starting Off: How To Sow Lupine Seeds

While you can buy lupines as established plants, you do get more of a range of colors and species when you choose to raise them from seed, as garden centers won’t stock every variety, though you may be able to order them if you ask.

It’s also worthwhile as it tends to be much cheaper to raise them from seed. Start sowing your chosen lupines in the first few weeks of spring. 

But before you throw them into soil, it’s important to cut part of the seeds open, as they have a tough coating that the seedlings may not break through. 

Soak these seeds in water for a whole day before you sow them, and this will help rehydrate the seeds, and ‘wake’ them up.

Sow them into moist soil, and you should see signs of germination in about 10 days’ time if you keep the seeds at a temperature between 50°F and 59°F (or 10°C and 15°C).

How To Grow Lupins

Lupines are very easy to grow, and while they can grow in a range of conditions, there are a few things you can do to get the very best out of them.

The ideal growing conditions can vary depending on the species you choose, but the general care is the same.

Sunlight And Position

Lupines like a very sunny position, and they are ideal for large or small gardens, as they will tolerate an exposed or sheltered area without any problems. 

For smaller spaces, consider growing alpine or dwarf species to match the space in your garden, but the larger ones can also be grown in containers if you prefer.

If you can put them in a warm position, this will bring the best out of these plants. Plant lupines in spring and early summer.

Some lupine species will need to be staked in open areas to support their growth, while others will remain upright by themselves without any issues.

Ideal Soil For Lupines

They prefer well-draining soil, which is either neutral to slightly acidic, and will provide you with gorgeous colors all summer long.

The soil doesn’t need to be high-quality, and these plants actually do better when the soil doesn’t have a lot of nutrients, so planting them straight in the ground without mulching them will be fine.

If your garden has boggy soil, or you live somewhere that’s typically cold and wet, you may want to grow lupines in containers instead, which allows you to give them the right soil and drainage they need. 

When To Water Lupines

Lupines like being watered regularly during the growing season, but they do need to be watered more when you first plant them, to settle the roots into the soil.

They will also benefit from the extra drink during prolonged dry spells. It’s worth noting that plants in containers will dry out more quickly than in the ground, so keep this in mind.

If you get cold and wet winters, it’s worth moving your lupines away from areas of your garden that are very exposed, as they have a better tolerance for cold when they aren’t so wet. 

Some lupines also do well in the dappled shade of trees, too.

When To Feed Lupines

Lupines are not very hungry plants, and the only time you will need to feed them is if you notice that the flowering season isn’t what it should be.

If that does happen, you can support them using feed, in particular a potassium-rich fertilizer is best, which will help support the flower’s development.

Should You Deadhead Lupins?

You don’t need to prune the plants themselves, unless you want to keep the area looking tidy when the foliage has died back in winter. 

Having said that, deadheading any fading or spent flowers will help produce a second flower spike during the season, if you do it early enough.

Can You Propagate Lupins?

You can propagate lupines by taking cuttings, and which type you need to take depends on the kind of lupine you have.

If you have tree lupines, softwood or greenwood basal stem cuttings are worth taking in spring, but unlike other cuttings, these will rot if humidity is too high.

For border lupines, take basal stem cuttings from the bottom of the plant in spring, when new shoots are at least 8cm tall.

To help avoid the new cuttings rotting before they can root, use perlite instead of compost.

Pests And Diseases To Watch Out For

Slugs, snails, and lupin aphids are pests that will feast on your lupins, so you will need to keep an eye on your plants, acting at the first sign of pests.

You can control them naturally to a large extent by encouraging their natural predators into your garden, including hoverflies, ground beetles, ladybirds, birds, and earwigs.

You can do this by making sure you plant a lot of flowers and plants that are native to your area, as well as building areas for wildlife such as bug hotels.

Powdery mildew and lupin anthracnose are the most common diseases you might see taking hold of your plants.

Lupin anthracnose causes leaf stalks to corkscrew, and you can also spot this disease by brown spots forming on the leaves and stems.

If you do see signs of this disease, destroy any affected leaves. If it has spread to the rest of the plant, you need to pull it up and destroy it responsibly so that there’s no chance of this disease spreading, either in your garden or elsewhere.

A good way of preventing disease is to space plants out, ensuring that enough air circulation can reach between the plants. If you do see signs of disease, don’t save seeds from infected plants.

Prune the affected areas, destroying any of the debris responsibly, to make sure that it cannot spread.                                                                                            

A Note On Potential Harm

Toxicity

Lupins are poisonous, so it’s worth growing a different plant if you have pets or children in your garden.

You will also need to wear gloves when collecting or sowing seeds, as well as taking cuttings.

Invasiveness

Lupines are classed as invasive species in many parts of the world. This isn’t just because they grow quickly, crowding native species and taking up the space that should be theirs, but also because their seeds are poisonous in large quantities.

This can cause problems not only for cattle, but also for herbivores.

When it does take up the space for native plants such as milkweed, this can impact the likes of monarch butterflies and other insects, as the monarch butterflies use milkweed as a host plant for their larvae.

So it’s worth checking to see if lupines are classified as invasive in your area.

Lupine Varieties You Should Try Growing At Least Once

There are so many varieties of lupines to choose from, and this can get overwhelming quickly. One of the best ways to start is to figure out how much space you have, and this will determine whether you want a tree lupin, a perennial, or an annual variety.

Here is just a snapshot of the many varieties available.

Lupinus ‘Towering Inferno’

A very striking variety, this particular lupine produces vivid orange flowers with yellow bases, and the flowers emerge pink at the top of the plant. This cultivar grows to about 90cm tall.

Lupinus ‘Polar Princess’

If bicolored flowers aren’t for you, or you have buckets of color in your garden already, why not go for an all-white variety? 

‘Polar Princess’ features brilliant white flowers, and these are densely packed along the flower spike, still making a great impact on any space. It’s also worth noting that this plant will grow to about 75cm tall, flowering a little later than other lupines.

Lupinus ‘Manhattan Lights’

One of the most dramatic lupins available is ‘Manhattan Lights’, featuring deep purple flowers with bright yellow fall petals, making a beautiful combination that will look perfect in any planting scheme.

It also helps that this variety can reach 90cm tall.

Lupinus arboreus ‘Lavender Spires’

A tree lupin, ‘Lavender Spires’ can reach a maximum height of 8 feet tall, perfect for larger spaces that could do with a dramatic display. Each raceme can reach 30cm long, featuring pale lavender flowers with deep purple fall petals.

These contrast well against the silvery green foliage, and will work well in most climates. Tree lupines are particularly useful for coastal gardens or rockeries, as they don’t mind poor soil.

Lupinus elegans ‘Pink Fairy’

A very beautiful dwarf variety is ‘Pink Fairy’, reaching a maximum of 60cm tall. It features white and pink flowers, and the pink matures to red as the flowers mature.

Lupinus havardii ‘Big Bend Bluebonnet’

A species hailing from Texas, this particular lupine can reach between 1 and 3 feet tall, depending on the growing conditions. The flowers appear on large erect stems, and produce deep blue and yellow flowers.

They bloom during early and mid-spring, and if you plant them alongside later-flowering lupins, you will have flowers for weeks!

Lupinus polyphyllus ‘Bigleaf Lupine’

For particularly wet or boggy soil, the ‘Bigleaf Lupine’ is a good choice, as these growing conditions mimic its natural habitat. Use them around ponds or in poorly drained soil for best results.

These lupines can reach between 3 and 5 feet tall, and the flowers can range from purple to blue, attracting plenty of beneficial insects into your garden.

Lupinus x hybrida ‘King Canute’

As you might imagine from the name, ‘King Canute’ is a hybrid lupine. It works well in pots, mixed borders, and even raised beds, with a clump-forming growth habit. 

It produces flowers in deep blue and white, and does best in a sunny position.

Lupinus x hybrida ‘My Castle’

While a relatively short-lived variety, ‘My Castle’ will add a lot of drama and color into any garden, reaching 4 feet tall in the right conditions. 

It’s also capable of self-seeding, saving you some work when it comes to replanting annual lupines.

‘My Castle’ features bright red blooms, usually with darker fall petals. It also helps that this variety grows very upright, so it won’t need staking.

Lupines As Nitrogen-Fixing Plants

As a legume, the lupine is what’s known as a nitrogen-fixing plant. This means that certain bacteria live in the roots, and these extract nitrogen from the atmosphere, and use it for their growth. 

Once they are done with the nitrogen, it becomes something that the plants can use – not just lupines, but also the surrounding plants – acting as a nutrient boost. 

This makes them a good companion plant, as it increases the levels of nitrogen in the soil, which benefits all the plants around it.

Final Thoughts

Lupines are beautiful plants that put on a show in any garden, with their unusual towers of brightly colored flowers, usually in two different colors or more.

Whether you choose to grow them from seed, cuttings, or buy established plants, they will make a large impact in your garden, introducing plenty of color and attracting beneficial insects.

It is worth checking, however, that the variety you choose is not invasive in your area, otherwise you may do more harm than good. 

It is also worth keeping in mind that lupines are poisonous, and can be deadly if ingested, especially in large quantities. 

It may be worth choosing different plants entirely if you have pets or children, or making sure there is no way they can reach the plants to begin with.

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