Slug Tales from Zone 6: Spring blossoms

By Soncirey Mitchell
Reader Staff

We’re more than halfway through March, and already the local stores are flooded with spring-planted bulbs, seed packets and wildflower mixes by the pound. Even though winter showed up (for the first time this year) in recent weeks, it’s still time to think about growing things, bearing in mind that ice and frost could be just around the corner.

March and April are usually the time for planning in our area — U.S. Department of Agriculture Zone 6 — but given how unseasonably warm it’s been all year, and that, as of press time, the forecast calls for upcoming 57-degree days, it’s fun to gamble on a few early plantings. 

It’s too cold and cloudy for most vegetables and summer flowers to germinate, but planting early cover crops is an easy way to improve soil structure and prevent weeds while waiting for higher temperatures.

Cover crops are plants sown en masse to “cover” the soil, preventing weed seeds from germinating or crowding out those that have already. These can be harvested or tilled back into the soil to act as a green mulch. Two cold-hardy cover crops ideal for North Idaho are clover and field peas, both of which are soil-building legumes that pull nitrogen from the air and store it in the ground for future plants to use.

These cover crops should be sown when soil temperatures reach the upper 40s, which you can measure by using a regular meat thermometer with a stem at least four inches long. Plant them liberally according to the instructions on the seed packets and ensure the area stays moist, which isn’t usually an issue in mud season. A few weeks before it’s time to plant your primary crops, cut down the peas or clover, then, using a garden hoe, chop them up and incorporate them into the soil to break down and feed the later spring plantings.

Always research all plants — but especially cover crops — before buying them. Big box stores will often sell bags of seeds that are ill-suited to North Idaho, such as the unfortunately named “hairy vetch.” Though technically not on the Idaho Noxious Weed List, which would make it illegal to plant, Bonner County lists hairy vetch as one of the “Invasive Weeds of Concern,” along with absinth wormwood, bull thistle, common tansy, marestail, red sorrel and St. Johnswort.

In those same box stores, alongside mountains of Easter paraphernalia, are spring-planted, summer- and fall-blooming bulbs. They’re flying off the shelves, so it must be time to plant them, right? Wrong. Most bulbs and tubers planted in spring originated in warm climates, like dahlias from Central America. They generally require soil temperatures of at least 65 degrees Fahrenheit to sprout; otherwise, they sit in the cold, damp soil and rot.

Still, most people are going to buy all the good bulbs before the late-May, early-June planting season actually arrives, so if you see something you like, plop it in your cart. Remember to check the USDA hardiness zone on the label: If it’s hardy to at least Zone 6, it can stay in the ground and come back each year, but if it’s something like a dahlia that’s only hardy to Zone 8, it will die in late fall. Either plan on buying new plants every spring or planting in pots or digging the tubers up every fall to store them indoors over the winter. Cold-hardy bulbs like alliums, irises and Asiatic lilies are tough enough to survive on their own.

To keep bulbs healthy and ready to plant while in storage for a few weeks or months, place them in a cool, dry, dark location, such as a basement or garage. Store them in breathable containers and keep individual bulbs separated by placing them in sawdust or wrapping them in newspaper (you can even use this edition of the Reader).

When it’s time to plant, think of how and when the bulbs will bloom. Planting in clusters will create a greater visual impact, and including early-, mid- and late-bloomers in each group ensures there isn’t a bald patch in the garden after the first flowers fade. Finally, consider each plant’s height and color, and organize them accordingly so they don’t clash or block one another. Follow the planting instructions on the bag, but generally plant bulbs two or three times as deep as they are tall and aim the pointed end up. If both ends look pointy to you, just plant it on its side — eventually, both you and the flower will figure it out.