Snowfall people who got our early enough to see Monday Morning, Snow was gone by 12pm

Over the past few weeks here in Southern Iowa we’ve had warm temperatures in the 60s and 70s which has pushed up growth from spring bulbs and a few other perennials. Trees and shrubs are still for the most part dormant enough not to be concerned about. Now we’ve gone into a cold snap and temperatures have plummeted well into the 20s at night, and we’ve even gotten some snow ( 0.50 or less all areas) All of which was melted by 12pm. What should be done to prevent damage to plants that may have come up?

There are a couple things that can be done when this occurs. One which I will discuss now is the easiest thing to do which is let nature take its course. Spring bulbs such as Tulips, Daffodils, Crocus and Snowdrops have natural defenses to prevent damage when this type of thing occurs. Also the shorter the plant, or the farther away from bloom they are the hardier it is. Most of the time the plants are fine, even when temperatures drop as lows as the lower 20s. I’ve seen snowdrops in full bloom survive lower 20s even though they looked bad and wilted in the morning, they purk back up as temperatures warm. It is VERY important not to touch or let animals walk over or near the plants when temperatures are below freezing because plants become very fragile when it is below freezing. If plants are to be covered do so before temperatures get too cold ( below 32.F) So for the most part spring bulbs are most often fine when left along as freezing weather arrives, however if very cold temperatures when in bloom it can damage the bloom for that season, but foliage is fine in most cases as plants bloom the next year. I have only seen 1 year where blooming Daffodils were knocked down late hard freezes, but they bloomed the next year.

Other perennials that could be sprouting now include Iris and Day lily, for these no action is required. These are both very early in their growth stages and even a hard freeze will not harm their blooms. I have never seen a case where freezes during early spring growth of these perennials harmed later blooming.

To some gardeners, including me at times, the over all thought of loosing that years crops of blooms is too much not to at least try to do something. For these people the best thing to do is cover with leaves, pile them enough to cover all the foliage. Many of times when it turns cold the biggest worries are something touching plants while their in the fragile frozen stage, of If snowfall is expected which can crush bloom stalks. For this I usually carefully put pots over sprouts which are under the leaves as well. This can be done when plants are young and small. Once spring bulbs reach a certain height sometimes trying to cover them ends up being more damaging then doing nothing. In all cases when I had blooming spring bulbs when a cold spell has arrived I have never had a total loss of the entire bloom crop. The biggest damaging thing I usually come across is crushing snow, falling ice onto plants, or something touching or moving plants when they are frozen and delicate.

Trees and shrubs once again at this point and usually do not require any action, as they are all dormant.

Horticulture Consultant,
 Derek McKay
Des Moines, IA
Contact information: [email protected]