Lupins are probably one of the most robust ornamental perennials in the garden. They tolerate sub-zero temperatures and get by in winter without any winter protection. Only if you keep lupins in pots on the terrace do you have to protect them from temperatures that are too low.
Overwintering lupins outdoors
Lupins that grow freely in the garden do not need to be protected from frost. They even withstand temperatures of minus 25 degrees (77F) without any problems. The perennial forms long roots that can penetrate up to two meters into the ground.
As a result, the plant has access to the groundwater even in the cold and does not dry out completely even in sub-zero temperatures.
It is often recommended to cut the lupines down to the ground in autumn for overwintering. Of course, you can do that. However, this is not necessary.
Most of the above-ground components will retract by themselves over the winter. The remains remain on the surface and are overgrown by the new shoots in the spring. In this way, they serve as additional fertilizer.
Protect lupins in pots from frost
Lupins in pots do not necessarily freeze to death at low temperatures. What really damages them is the dryness. It occurs when the moisture in the soil has frozen rock hard and the roots can no longer absorb liquid.
The lupine, therefore, dries up sooner. Therefore, it needs winter protection so that it can absorb some water even in winter.
- Place the pot on a styrofoam plate.
- Cover the plant with branches of conifers
- Cover the pot with bubble wrap, bags, or cardboard
- Place the pot in a wind-protected corner
- Give some water during long dry periods
Preparations for the winter
Shorten the lupine in the pot and cut off all the inflorescences. You don’t have to cut the plant down completely.
Cover the surface with a permeable material. Fir branches are well suited because they keep out the cold but still allow moisture to pass through. Then the earth will not mold.
Older plants that are no longer producing as many flowers should be uprooted in autumn. If you divide the root and plant the sections before winter, you will get young plants. They already flower the following year, so the missing perennials are not even noticeable.