Protect garden and plants from frost

Rosa pimpinellifolia - mit Frost © Isabelle van Groeningen

Rosa pimpinellifolia

(Deutsche Version) Clear skies have finally caused the night-time temperatures to drop below zero. This means the end for some plants that do not tolerate frost, it also meant stunning mornings with plants glistening in the crisp early morning light as each minute detail is amplified by the tiny ice crystals that have formed overnight. For Berlin this is a relatively rare phenomenon. Not that we do not get frosts, but usually the air is rather dry in winter, so that fewer ice crystals form. The heavy hoarfrosts that used to be a regular occurnece in our English garden, are a rare event.


The first frost victims

Rosa 'Munstead Wood' © Isabelle van Groeningen

Rosa ‘Munstead Wood’

I am always astonished to see how frost-proof some flowers are. The last of the heavily scented, dark red David Austin roses ‘Munstead Wood’ was coated in a thick layer of ice in the morning, by afternoon the flower looked as if nothing had happened. The nasturtiums on the other hand were a sorry, soggy mess. They do not tolerate any frost at all. Cosmos was also past its best, the new hybrid ’Cupcakes’ looking like jellyfish.

Bring in your dahlias

Dahlia © Isabelle van Groeningen


Dahlias too got frosted. Now is the time to dig them up and dry them off in a cool, dry shed or garage before storing them in a cool, dark place for the winter. A box lined with some newspaper and filled with leaves will do. Make sure you label them so next spring you know which ones go where in the border. As you clear annuals and dahlias, use the opportunity to plant your bulbs, if you have not done so already!

Overwintering frost-sensitive plants

Bougainvillea © Isabelle van Groeningen


Our wonderful gardening team has been busy this week with their annual giant tetris-game: bringing in all the frost-sensitive plants, and fitting them into the limited space available. We do have many greenhouses, but not all are guaranteed frost-proof. Although many will tolerate a few cold nights, all the citrus plants, Oleander and Bougainvillea have been brought inside. Also the succulents like Agave, Aloe and cacti are now under cover. The high water-content in the gel-like center of their leaves will not cope with much frost.

Plants need a rest

Evergreen plants like olive trees do not go fully dormant, but they do require a period of rest during these darker months where the daylight levels are low and the temperatures low. You cannot overwinter them in a dark cellar. Therefore you must keep them cool, stop feeding them, and do not water them too much. Just keep them slightly moist. If standing too warm, the will continue to grow, producing long, weak and etiolated shoots that will collapse when moved back outside in spring.


Make sure you switch off and drain your external taps and irrigation systems!