Don Kinzler, Published October 25 2013
Growing Together: Garden's respite: Winter an opportunity for well-earned nap
Let’s put the yard and garden temporarily to bed. They’re just sleeping, not dead. The following tasks help us get ready for spring.
1. Before the soil freezes solid, which is usually during the first half of November, anything you’ve purchased but didn’t get planted needs our immediate attention. All potted trees, shrubs, and perennials are better planted rather than over-wintering in pots above ground. If a plant can’t go into its permanent location, sink it pot and all into the soil of a temporary sheltered flowerbed or garden.
2. It’s the last chance to collect seeds from cleome, four o’clock, zinnia, marigolds, cosmos, rudbeckia and other plants before the seeds are dispersed by nature. Allow to dry, then store in tightly closed containers in the refrigerator.
3. Fall cleanup in the vegetable garden helps reduce next season’s disease and insect problems because organisms over-winter on plant refuse in and around the soil. Pull and remove squash, cucumbers, melons, tomatoes, peas and beans. Weeds that contain seed heads should be carefully removed to reduce scattering during winter. Annual flowers can be pulled and discarded now.
4. Soil in gardens and flowerbeds benefits from fall tillage even if just slightly. The wet autumn has made deep tilling difficult. Turning the soil over before freeze-up helps kill insects and disease organisms by exposing them to the winter elements.
5. In the perennial flower bed, cut tops to slightly above ground level and remove all that showed disease symptoms such as peonies, phlox and hollyhocks. Remove tops of iris and daylilies which become mushy by spring.
Healthy tops of other perennials and ornamental grasses can be left over winter for landscape beauty and wildlife habitat.
Allowing the tops to remain catches snow, which provides good insulation for perennials borderline in hardiness like some mum varieties.
6. Apply protective mulch after several hard freezes and plants are completely dormant. The object is to keep the soil evenly cold and the plants dormant so they aren’t exposed to damaging freezing and thawing, which confuses plants, tears roots and can heave plants out of the soil. Tender perennials and strawberries should be mulched for this reason.
Mulch also keeps the soil from becoming extremely cold and protects stems of borderline hardy shrubs, especially during open winters lacking snow cover, which is nature’s great insulator. Leaves, straw and hay work well as mulch applied 6 to 12 inches thick or mounded around the bases of borderline shrubs and plants. Grass clippings tend to mold and pack too tightly.
7. Rose leaves are best raked and removed to reduce black spot and powdery mildew. Tender hybrid tea roses can be covered after several hard freezes. Styrofoam rose cones aren’t enough. But they work well if stuffed with leaves or straw so the mulch is in contact with rose stems, which might need pruning to allow cover.
Truly “hardy” shrub roses don’t need winter cover, although mulching can help them become taller by preventing dieback of stems that might be above snow cover. Circles of chicken wire filled with leaves or straw work well. Some shrub roses labeled hardy might not necessarily survive in our zones 3 and 4. The widely sold knockout series would benefit from protective mulch.
8. Tree leaves can be composted rather than hauled to the landfill. Or they can be spread onto garden and flowerbeds and worked in a bit. A thin layer of leaves can be left on the lawn, run over with the lawnmower several times and allowed to filter into the grass’s root zone. They’ll decompose into beneficial organic matter for the lawn.
9. Wrap tree trunks to prevent winter sunscald to thin barked trees on bright sunny winter days. South-facing tree trunks can thaw in the bright sun, followed by nightfall freezing. Freezing and thawing tears bark and causes cracks. Especially vulnerable are fruit trees, lindens, maples and trees less than five years old. Tree wraps are best removed each spring, especially important if tight.
10. Remove plants from patio pots and containers. The soil mix can be reused next spring if it’s high quality with the addition of some fresh.
11. Take a few minutes to write down plant names in case labels are lost. If you’re really energetic, put a coat of vegetable oil on garden tools after scrubbing to prevent rust formation.
12. Now we’ve earned a breather. Let’s mentally revel in this year’s successes. Oh, and by the way, I’m happy to announce we’re going to be “Growing Together” all winter long.
Don Kinzler, a lifelong gardener, worked as an NDSU Extension horticulturist and owned Kinzler’s Greenhouse in Fargo. Readers can reach him at firstname.lastname@example.org