Some plants are not adapted for a harsh winter. They need to be protected from falling temperatures, wind and excess moisture.
Here are the most affected plants and how to take care of them.
Here are the non-hardy plants that will be most impacted by the cold temperatures of winter.
Tropical plants: hibiscus and orchids. They are less tolerant to cold, so you should pull them inside or protect them, starting from mid-September or when temperatures are approaching 50°F/10°C. Place them in a bright room with level temperatures.
In the case of some orchids, such as dendrobium or cymbidium, you can let them breathe outdoor once in a while to get a good flowering next season.
Mediterranean and orangery plants: oleander, pelargonium, banana, palm, bird-of-paradise, bougainvillea, citrus, lantana. Protect them at the time of the first frost (mid-October, mid-November). Tuck in those in containers into a cool, ventilated area like a garage or basement, with a little light.
Cacti: like tropical plants, you have to put them inside as soon as possible, into a fresh and bright room.
Other frost-susceptible plants: geraniums, fuchsias, datura, summer bulbs, etc.
Note that for these plants, watering will be limited to a minimum to maintain a slight humidity.
Tuck away the most cautious plants grown in containers into a room kept frost-free, ventilated and well lit.
To avoid thermal shock, put them inside before the first frost, when the gap between outdoor and indoor temperatures is low.
If you do not have a porch or adequate shelter, it is better to leave them outside. They’ll survive winter easier than they’ll survive a room that is too heated.
Here are some tips:
- Put the containers close to the walls.
- Put them in a corner away from cold winds (east/north).
- Elevate the containers so they are not in direct contact with the cold ground.
- Wrap the most fragile containers with newspapers, bubble wrap or Styrofoam, which provide good isolation (especially on the underside). Protecting the container from the cold is protecting the plants’ roots it contains.
- Cover the plants with a wintering veil (2/3 layers, based on the fragility of the plant).
- Mulch the potted plants, making sure it cannot fly away.
In the house, cacti and other succulent plants should be shielded away from heat, although they should be given the most light. For euphorbia and fake cacti, ideal temperature usually is around 65°F/18°C
Until March, these plants do not need to be watered, unless you notice wilting of leaves and stems.
Shrubs will need to have their trunk wrapped with a thick mat (reed, straw, etc.) maintained by strings. Double the thickness for the most sensitive plants.
Non-hardy bulbs such as dahlia, canna, gladiolus, begonia. They need to be torn from the earth and kept in a dry unlit room.
Fragile trees, such as olive or banana trees in cold areas (where temperatures go below 25°F/-5°C in winter) must be fully protected. Branches need to be surrounded by a veil and strings to hold it it in place. Around the trunk can be attached a strip of burlap or tape. At the foot of the tree, a thick mulch will protect the roots.