October 10, 2024, 11:17 am | Read time: 5 minutes
Lupin (Lupinus) enriches every garden with flowering candles and beautiful butterfly flowers. It also acts as a green fertilizer in flowerbeds and easy-care gap filler in the border. myHOMEBOOK author Marike Stucke introduces the garden plant and gives tips on how to care for it.
The lupin actually originated in North America and made its way to Europe at the beginning of the 19th century. Introduced as an ornamental plant, it quickly spread into the wild and is now native as a wild perennial. There are both annual and perennial Lupinus species, with perennial varieties commonly found in gardens and the annual sweet lupin used in agriculture as a green fertilizer crop. Both types share the characteristic of beautiful and long-lasting blooms that attract numerous pollinating insects from early summer through fall.
Overview
Planting lupins
The annual lupin is sown directly into the flower bed in May and acts as a green fertilizer or simply a decorative garden flower. Here, it germinates after a few days. Perennial lupins are available from garden centers and are suitable for outdoor use and in containers. However, they should ideally be planted by summer to ensure the plants have sufficient time to establish roots before the onset of cold weather at year’s end. Moreover, perennial lupins can also be sown from seed.
Appearance/growth
As with many plant species with a wide range of varieties, the question of the size of Lupinus must be answered as follows: it depends. Some varieties grow to a height of around 80 centimeters, others 120 centimeters, and some even up to 300 centimeters. However, the most striking feature from early summer onward is the magnificent flower spikes, where the individual blossoms open sequentially from the bottom up. The plants, therefore, look as if they are almost constantly in bloom.
Location/soil
Sun and plenty of space are the best conditions for abundant lupin flowering. The shadier the location, the less splendid the flower candles can look. Lupinus is not demanding in terms of soil quality, which is why the annual lupin is also favored as a green fertilizer on depleted soils. However, the soil should not be too firm or impermeable, as lupins do not tolerate waterlogging well.
Varieties
A fundamental distinction must be made between annual sweet lupins and perennial perennial lupins.
- Sweet lupin: Sweet lupins are annual lupin varieties whose seeds are edible. In the Mediterranean region, pickled lupin seeds are a popular snack, but due to their high protein content, meat substitutes are also produced from sweet lupins.
- Castle series of perennial lupins: The English horticulturalist George Russel bred several different perennial lupins in the 19th and 20th centuries, all of which belong to a series and are still very popular today. The Castle series includes the white ‘Bigleaf’ variety, the yellow ‘Chandelier’ variety, and the crimson ‘Noble Boy’ variety. The varieties in this series grow up to 80 centimeters tall.
- Dwarf garden lupins: As the name suggests, dwarf garden lupins are significantly smaller than other varieties and reach a maximum height of 60 centimeters.
Planting and care tips How to cultivate a goji berry bush in the garden
Delicate summer flowers with bright colors Planting and care tips for cosmos
Planting and care tips Goldenrod in the garden – what to know about this bee magnet
Lupin care
Watering
Lupinus needs regular water, and the soil should never dry out completely. However, you should not overdo it. Lupins are prone to root rot when waterlogged.
Fertilization
The annual lupin is popular as a green fertilizer because it thrives in nutrient-poor soil and can suffer from overly generous fertilization. A little compost around the plant’s root area in spring is usually sufficient.
Pruning
The lupin does not need pruning per se; only the flower candles should be cut back shortly after they have faded. This can lead to further flowering in late summer.
Winter hardiness
As their name suggests, annual lupins are not hardy and are cut close to the ground in the fall (or mowed down in larger beds) and left as a mulch layer. Perennial varieties sprout anew every year and are hardy if they are not planted too late in the year (until summer).
Poisonous
Garden lupins are highly toxic in all parts and are therefore not suitable for gardens frequented by children or pets. The seeds of sweet lupins are non-toxic, even when raw. When raw, they taste similar to peas. After cooking, the taste becomes nutty.
Propagation
The simplest method of propagating lupins of any variety is through seeds. Garden lupins can also be propagated by dividing the rootstock. The third method of propagation is by cuttings.
Alternatives
Snapdragons look similar to lupins, even though they belong to a different plant family (plantain family). However, they require more nutrients.
Bee friendliness
Bees and bumblebees are attracted to the flowers of lupins and can easily access nectar and pollen thanks to the shape of the flowers. Lupinus is, therefore, an enrichment for any bee pasture.
Use
Annual lupins are commonly utilized as green fertilizer, whereas garden or perennial varieties primarily serve to beautify the garden. The flower ‘candles’ are also popular cut flowers.
Diseases and pests
Slugs and snails are particularly fond of the young shoots of Lupinus and can completely devastate them. They can usually do little harm to larger plants. Lupin aphids are otherwise the greatest pest threat to lupins. Powdery mildew can also attack the plant.