How to protect Plumbago from the cold in winter?

Why protect Plumbago in winter?

Plumbago is not hardy: it is a tender plant that cannot withstand temperatures below -3 °C. Plumbago, frost, and cold do not mix well! In regions where winters are harsh — the north, east, and centre of France, as well as high-altitude areas — it must be sheltered or covered with appropriate protection. Even in coastal areas or the south, a late or early frost can damage the stems and compromise the following year’s flowering, especially on young plants or those grown in pots.

When to start winter protection for Plumbago?

It is advisable to install protection for Plumbago against frost when night temperatures drop below 5 °C and before the first frosts are forecast, generally between late October and mid-November depending on the region. In pots, Plumbago should be brought into a bright, frost-free space. In the ground, action should be taken before severe cold sets in to avoid irreversible damage.

Unlike a Plumbago grown in the ground, a potted specimen can be brought under cover to protect it from the cold in winter.

How to protect Plumbago from frost and cold?

How to Protect Plumbago in the Garden During Winter?

In the garden, Plumbago is exposed to temperature fluctuations and winter humidity. The goal is to preserve its roots and branches.

• In mild winter regions: lightly cut back the stems to reduce wind resistance. Apply a mulch layer (15 to 20 cm) of dead leaves, straw, or wood chips around the base. Cover the plant with a winter fleece securely fastened to limit heat loss while allowing air circulation.
• In cold regions: cut the stems back to 30-40 cm above the ground. Protect the stump with a thicker mulch layer (20 to 30 cm), then place a bell or protective box filled with dry leaves on top to create additional insulation.

Cut back the Plumbago and apply a good layer of mulch to protect the stump.

How to Protect Potted Plumbago During Winter?

In pots, the root ball cools more quickly than in the ground, making the roots very vulnerable to frost. A single cold night can severely damage them.

• In cold or temperate climates: bring the Plumbago indoors before the first frosts to a bright, frost-free space, such as a conservatory, unheated greenhouse, winter garden, or a non-heated room maintained between 5 and 10 °C. Significantly reduce watering, keeping the root ball slightly moist, and stop fertilising throughout the wintering period. Avoid dark and confined spaces, which promote fungal diseases.
• In Mediterranean or mild coastal climates: if temperatures rarely drop below −2 °C, you can leave the potted Plumbago outside all winter. In this case:
  • Place the pot against a south-facing wall to benefit from accumulated warmth;
  • Surround the container with winter fleece or hessian to protect the roots;
  • Elevate the pot slightly to avoid direct contact with cold, damp soil;
  • Prepare a protective cover to place over the foliage if a more severe frost is forecasted.

If you do not bring it indoors, place the pot against a south-facing wall, sheltered from cold drafts. In the right photo, the pot has been slightly elevated, which helps insulate it from the cold.

What to do after winter: waking up the Plumbago from dormancy

When all risk of frost has passed, usually in April or May depending on the regions, gradually remove the frost protection for Plumbago to avoid thermal shock.

• In the ground, remove the thick mulch and cut back any dry or damaged stems to encourage recovery.
• In pots, take the plant outside on mild days, gradually increasing its exposure to sunlight.
• Resume regular watering and apply a fertiliser for flowering plants to stimulate growth and prepare for abundant flowering.