Most evening primrose varieties are incredibly hardy, meaning you can usually breeze through the cold months without worrying about extra winter protection. This includes popular favorites like the Common Evening Primrose (*Oenothera biennis*), Large-flowered Evening Primrose (*Oenothera glazioviana*), and the Small-flowered variety (*Oenothera parviflora*).
Easy Winter Protection for Sensitive Varieties
If you’re growing a slightly more sensitive variety, a little TLC goes a long way. You can protect them from the frost by simply covering them with some brushwood or evergreen branches. Just make sure the plant still gets enough airflow and that water can drain away easily—you definitely want to avoid any rot! Pine or spruce branches are perfect for this; as they naturally drop their needles, they gradually increase the airflow just when the plant needs it most. It’s also a smart move to give your young, newly planted primroses a bit of this extra cover during their first winter.
Overwintering Potted Plants
Even though these beauties are tough in the ground, it’s a different story for container gardening. Whether your pots are ceramic, plastic, or terracotta, the cold hits a container from all sides, which can freeze the root ball much faster than the earth would. To keep them cozy, I recommend wrapping your pots in bubble wrap or using foam insulation to give those roots a fighting chance against the deep freeze.
Watch Out for Rot!
Here’s a pro tip: your evening primrose is actually more likely to die from rot than from the cold. If water pools up and can’t drain, you’ve got a problem. If you’re keeping them in pots on your patio or in the garden, double-check that your containers have drainage holes. If they don’t, grab a drill! I like to place a piece of broken pottery (a “crock”) over the hole so it doesn’t get clogged with soil. During the winter, it’s also a great idea to “feet” your pots—elevate them slightly off the ground to make sure water can flow out freely.
A Tough Plant Against Pests and Disease
One of the best things about evening primrose is how resilient it is. It rarely deals with pests or diseases. Every once in a while, you might spot a bit of downy mildew, but don’t reach for the harsh chemicals! A natural liquid fertilizer or a homemade plant wash usually clears that right up.
