(Editor's Note: This article was originally published on March 4, 2008. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)
Lupinus polyphyllus is the most popular of these stately plants. They can grow up to 5 feet high and, as far as I am concerned, should be a permanent fixture in all gardens.
Lupines come in both annual and perennial varieties. Lupines do not like hot weather and do best in the Northeast and Canada. They also grow well in the Pacific Northwestern U.S. and some parts of California. They also grow abundantly throughout Europe as far north as Norway. In some countries, like New Zealand, they are considered a noxious weed, taking over vast areas and forcing out native plants. There are species of lupine to be found on nearly every continent.
Due to their ability to enrich the soil with nitrogen, they can be planted in the poorest of soil and thrive. Therefore, they do not require to be fertilized, although, if planted in fertile soil with lots of good organic matter present, they will produce the best display of large flower spikes. They can withstand full sun or the lightest shade. I have them planted in both areas. Those in full sun put on a much better display, the ones I have in shade can still hold their own, the only difference being, the shaded plants are shorter, with equally short, yet still showy spikes of flowers. Still beautiful in either case. They do love their water, so bear this in mind if you are in an area with watering restrictions. Some of the newer hybrids will tolerate short periods of drought.
For the best effect, Lupines should be planted in large groups. Their spectacular flower spikes can reach anywhere from 12 to 60 inches in height, making them a good focal point in any perennial bed. Blooming in June and July, their flowers have a noticeable honey scent and are attractive to many butterflies, as well as humming birds and bees. They come in many colours, pink, red, purple, white, violet, apricot, blue and even yellow. They have attractive blue-green, almost tropical looking leaves. Deadheading spent flower spikes will prolong the blooming time and they will bloom again, though not as spectacularly, in late summer. The spikes are great as a cut flower, alone or in an arrangement.
If you want to grow your own, they are easily grown from seed. Lupine seed pods, when ripe, explode. When they turn yellow and rattle inside, place them in a paper bag and let them explode, then gather them up. Simply soak the seeds overnight and press into soil. Lupines do not like to be transplanted, so if you have to start them in pots, be sure to move them to the garden when they are 3 to 6 inches high. Be sure to plant them where you want them, the adult plants, due to their deep tap root, transplant miserably. I have had some success, though, moving them first thing in the spring, when they are just beginning to show, a few inches high. They must be watered in well. The best way to grow from seeds, in my opinion, is to scatter them in the garden in the fall.
Some Lupines have a high alkaloid content, making them poisonous to both humans and animals. Keep this in mind if you have critters or children that tend to taste your garden. This fact should also make them deer and rabbit resistant. I have never had them eaten by deer, but the odd nibble has been taken by rabbits. Lupines can be susceptible to powdery mildew, so good air circulation is needed. In my zone, I have never had a mildew problem on my Lupines(knock on wood), but my gardens are in a very open area. Crown rot can occur if kept too wet, so a well draining soil is helpful. Aphids can be a problem. I have had Lupines growing in my perennial beds for 15 years. This past summer was the first time I have had an aphid problem. They were horribly infected, after blooming, almost overnight. I solved the problem by cutting them right to the ground and removing any dead foliage in the area. They grew back stronger than ever.
This wonderful, old fashioned plant is a mainstay in my gardens. I look forward to them every year. Scattered in large groups in every one of my perennial beds, they put on a wonderful early summer show. They play nicely with other plants and are relatively problem free. They self seed so readily, I end up having many to give away or move around, and I can always find a home for more. If you have well behaved pets and children, please consider them for your gardens. They are the perfect cottage garden plant.
Photos courtesy of PlantFiles