By: Joanna Manor
Living in the Midwest, we have all seen late frosts in May, and sometimes even snow in April. Why then do we sell Early Spring annuals starting mid March? Cold hardy annuals are just that – cold hardy. Pansies can survive air temperatures as low as 25°, but be prepared for them to show you signs of stress after a night that gets below 32°.
Signs of stress include wilting leaves and blooms, and leaves that turn a darker shade of green. No need to worry though, the sun and late morning rising temperatures will often bring the Pansies back to life. Though you need to be prepared to clean through damaged blooms after a cold night, Pansies are bred for and thrive in cooler temperatures. If you have planted your Pansies in the ground, you are more likely to see this type of stress on the plants. You can cover them with a frost blanket if that is an option for you, but make sure to not to let the blanket lie directly on the plant because it could potentially do more damage than leaving them uncovered.
Perhaps you have designed a few pots and used other cold hard annuals like Ranunculus, Nemesia, Ivy, Snapdragons, or Stock. While these plants can tolerate fairly cold temperatures (some down to 35°), they may not bounce back as fast as a Pansies from a frost or freeze. Err on the side of caution with these cold hardy annuals, cover your pots if temperatures are going to get below freezing at night, pull them into the garage, or bring them under the cover of a porch or awning. If you are going into a hard freeze, we would strongly suggest pulling the pot into a semi heated area if possible.
Early Spring annuals bring color and joy to our landscapes after a long hard winter. Some Early Spring annuals can last into summer, but they don’t always thrive. We carry Pansies and Violas in the early spring months because once May hits, they don’t like the warmer temperatures. That’s not saying they will die, but they do best in cooler temperatures. You may see blooming or growth slow, or burnt edges on leaves if planted in the full sun. Most growers don’t offer Pansies, Violas, Stock, and Ranunculus after May, but by then the Greenhouses are full, and we’re ready for a heat tolerant change.