The temperature dipped to minus-7 earlier this month in the Twin Cities. Three days later, it soared to 44 degrees, and spring-drunk Minnesotans were out raking still-frozen lawns.
Give us credit for enthusiasm.
But at this time of year, it’s best to restrain yourself: You can do more harm than good by doing too much too soon.
Even walking on still-soggy lawns and garden soil can be damaging, compacting the soil and hurting plants. Though it looks like gardeners in the Twin Cities will see their lawns and gardens dry out quickly this spring, it could still get cold enough to harm plants. In Zone 4, where the Twin Cities is, the average last date of a killing frost is May 10.
We’ve got a way to go for worry-free gardening.
So what can you do in the garden in the waning days of what looks like a mild end to winter? Here are some tips.
Don’t rake until the lawn is dry. Your shoes shouldn’t squish as you walk on the lawn. If your footsteps leave impressions in the grass, it’s too early. When you do rake, do so gently. Otherwise you could rip up new grass from the roots.
If temperatures are above 30 degrees at night, you can move the winter mulch away from bulbs that are planted in hot spots, like the sunny south side of your home. Bulbs that end up growing through mulch will flop if you wait too long to pull it back. (I mound the leaf mulch against the house or stack it nearby so I can put it back if the temperature dips again and my tulips need protection.)
Cut back your perennials if you didn’t do so in the fall, as long as the soil isn’t sodden. Be sure not to compact the soil around your plants by walking on it. Remember, it’s easiest to remove dead foliage before new foliage is showing.
Don’t uncover tender or picky perennials too soon. Plants that I cover with lots of leaves in the winter (think Endless Summer hydrangea) often show green shoots with the kind of warmth we’ve had. But I’ve made the mistake of pulling the leaf mulch off too early, only to lose an entire year of blooms when the temperatures dip into the 20s and the new growth is burned.
I now leave Endless Summer covered in leaves until mid-April, unless the long-range forecast shows an extended spring heat wave. While growth under mulch may be weak and white, it usually quickly toughens up once it’s uncovered.
It’s still a good time to prune trees. With no leaves, you or your arborist can clearly see the structure of the tree. But time’s a wasting — you need to finish pruning oaks before April 1 because of risk of oak wilt. Oaks shouldn’t be pruned again until July.
If you have shrubs that need thinning, prune shrubs before the leaves sprout. But be aware that if you prune spring-blooming shrubs that flower on last year’s growth, like lilacs, azaleas and rhododendrons, you will cut off this year’s flowers. Spring-blooming shrubs should be pruned immediately after they finish flowering. Here’s a good guide to pruning from the University of Minnesota: http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/pruning-trees-shrubs/#renewal-pruning
Plan. It’s a great time to look at your dormant garden and figure out which plants should go where and which perennials need dividing or moving.
So put that rake away for now, kick off your shoes and practice some patience.
If you really want to get your hands in the dirt, you still have time to start seeds for this year’s garden. Tomatoes, marigolds and zinnias are among the plants that can still be sown and will be ready to transplant in late May.
Mary Jane Smetanka is a master gardener and a Minneapolis-based freelance writer.