How to determine a plant's hardiness?

A Dicksonia in Normandy?

– Michael, that’s amazing! You have a Dicksonia in your garden. But is it hardy enough to grow without any issues in your garden?

– Oh wait, Olivier! It’s hardy here, but let’s not forget that when we talk about hardiness, it’s not just about frost…

The components that define a plant's hardiness

Frost or cold are indeed one of the factors that contribute to the determination of hardiness for a given plant. However, this is not the only factor:

• the soil is also a factor to consider. If it is well-drained, one might attempt to maintain plants whose hardiness seems marginal for a given region. For example: a plant reputed to be hardy down to -8°C could be tried in a region where winter temperatures drop below -10 or -12°C if planted in well-draining soil;
• precipitation (total precipitation: rain, snow, hail…) and humidity (the amount of water vapour in the air): if the humidity level is not high enough for certain plants, they will die either in summer or in winter when frozen water is no longer available to the plant. Conversely, if the soil retains too much water in winter in humid regions, some plants may suffer. This water can also remain within the plant itself (palms, arborescent ferns…), which will have serious consequences when frost occurs;
• wind: whether the plant is protected from cold winds or, on the contrary, very exposed.

Numerous criteria will nuance the hardiness of a plant, allowing for the planting of more sensitive palms, for example, in certain gardens

Plantfit can help us!

– Do you know what would be great, Michael? It would be to have an app that takes all the parameters into account (soil, rainfall, climate, sunlight…) to help gardeners choose the most suitable plants. That would be amazing!

– Well Olivier, to ensure that a plant is suitable for its garden, Promesse de Fleurs has actually developed a perfect app for that. The tool is called Plantfit. It’s a configurator that allows you to find out which plants are truly suitable for your garden based on your locality, soil, humidity, and the gardener themselves (gardener’s experience and time spent in the garden)…