Lupinus
( loo - PYE - nuss )
At-A-Glance InformationThis genus of annuals, perennials, and evergreen shrubs, commonly called Lupine or Bluebonnet, needs full sun and have varying water requirements. The flowers on these plants will attract butterflies and hummingbirds to your garden. They are mainly native to the western United States, but are found in a wide range of habitats. Spikes of flowers form in varying seasons. Take care when planting these beauties near livestock, as the seeds of some species may be toxic to them.
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Lupinus Species and Varietals
The genus Lupinus includes about 200 species and is a member of the plant family Fabaceae. It includes two subgenera, Platycarpos and Lupinus. The best growing zones for Lupine vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.
Lupinus arboreus This species takes the form of an evergreen shrub and is best in zones 4, 5, 14-17 and 22-24. It is native to California's coastal areas and reaches 5-8 feet tall and wide. Flower clusters bloom in yellow, lilac, blue, white or a mixture of these colors. Great beachside plant that needs little to no water. |
Lupinus hybrids
These perennials grow best in zones A1-A3, 1-7 and 14-17, and reach 4-5 feet tall and 2 feet wide on average. They need regular water for best performance. Varieties are outlined below.
These perennials grow best in zones A1-A3, 1-7 and 14-17, and reach 4-5 feet tall and 2 feet wide on average. They need regular water for best performance. Varieties are outlined below.
Russell Hybrids
These bloom in late spring or early summer and have tall flower spikes in white, cream, yellow, pink, red, orange, blue, purple, and bicolored. |
Little Lulu and Minarette
Dwarf strains that reach about 1.5 feet tall and wide, |
New Generation Hybrids
Sturdy plants that do not need staking to stay upright under the weight of their own blooms. Ling lasting, requiring replacement only every 7-8 years. Mildew resistant with bright colors. Bloom from spring through late summer. |
Lupinus microcarpus densiflorus (Lupinus densiflorus) This annual flowering plant grows best in zones 3-24 and is native to California. They grow 1.5-2 feet tall and wide, and come in white, lavender, purple, yellow and pink. Sow in place in fall for a springtime bloom season; these need moderate to little or no water to perform well. Variety 'Ed Gedling' (pictured) is a great choice variety of this subspecies with yellow flowers. |
Lupinus nanus (Sky Lupine) This annual grows best in zones 3-24 and is native from California up to British Columbia. Reaches 8-24 inches tall and 9-12 inches wide. Flowers bloom in springtime and are a rich blue marked with white. Sow seeds in fall or winter. No irrigation needed except for in desert zones. |
Caring for and pruning Lupinus shrubs
Plant your Lupine shrub in full sun to partial shade, where they will receive at least 6 hours of sunlight each day. Soil should be well-draining with a slightly acidic to neutral pH (between 5.0 and 6.8). These plants are nitrogen-fixing, and can tolerate poor soil conditions to a certain extent. They are relatively drought-tolerant once established (for the most part, this depends somewhat on the species grown), but will need consistent moisture for the most part especially during their active growing period. When the top inch of soil feels dry, water deeply. Apply a layer of mulch to increase soil moisture retention. These flowers do not require much fertilization, however if soil is poor, these flowers may benefit from a springtime feeding with a balanced, slow-release fertilizer.
Deadhead flowers as they fade to clean up the appearance and to encourage more blooms to pop. These flowers do not need to be 'pruned', though it is a pretty common practice to take them down to the ground in early springtime after winter's chill has decimated the foliage. Annual species can be replanted each subsequent year. Perennial varieties will benefit from being divided every so often to create more root space, however this is a delicate procedure for the most part as these plants have long taproots and do not always survive division and replanting. The best time to divide is in the spring or fall when the plant is not actively flowering.
Deadhead flowers as they fade to clean up the appearance and to encourage more blooms to pop. These flowers do not need to be 'pruned', though it is a pretty common practice to take them down to the ground in early springtime after winter's chill has decimated the foliage. Annual species can be replanted each subsequent year. Perennial varieties will benefit from being divided every so often to create more root space, however this is a delicate procedure for the most part as these plants have long taproots and do not always survive division and replanting. The best time to divide is in the spring or fall when the plant is not actively flowering.
Propagation
Lupinus can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Lupine, follow the instructions below:
Propagating Lupinus by Seed
Propagating Lupinus by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost, gloves, and pots (12 inch pots will do, and these are only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring or fall (after the plant has entered dormancy and been cut to the ground, but before it has begun its new spring growth), and needs to be done every four to five years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:
Propagating Lupinus by Seed
- Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
- Harvest your seeds. The seed pods on Caesalpinia plants are pretty easy to spot, they're large and dangle from the branches, left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
- Caesalpinia seeds have a hard coating that protects them, but this coating also makes it a little difficult to get them to germinate. We can help the process along by scarifying them with sandpaper (or simply rubbing them against an abrasive surface). Do this with as many seeds as you can; they will probably not all sow, and the ones that do will be of varying characteristics. The more seeds you plant, the more chances you will have to get the resulting shrub you want. Place your seeds in lukewarm water for six hours. Viable seeds will sink to the bottom, and non-viable seeds will float to the top. You can discard any seeds that float.
- Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
- Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Propagating Lupinus by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost, gloves, and pots (12 inch pots will do, and these are only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring or fall (after the plant has entered dormancy and been cut to the ground, but before it has begun its new spring growth), and needs to be done every four to five years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:
- Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the taproot. Once you have worked it up out of the ground, lay it out.
- Start to tease apart the roots with your gloved fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick tuberous section.
- Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divided tubers about an inch under the soil surface and water thoroughly.
- Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout!
Problems and Pests
The common pests and diseases that affect Lupine plants include:
- Aphids
- Slugs
- Snails
Gallery
Videos
All about growing Lupine.
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Lupine growing tips and tricks.
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How to grow Lupine from seed.
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What to do after your plant's flowers have faded.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 423, Lupinus
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