It’s the time of year to ready our gardens for the upcoming fallow winter season and prepare for next year’s growth. We do this knowing that regeneration will be occurring in our soil, with the microbes and with overwintering insects. Here are tips for you to best help this process take place, while still having an aesthetically pleasing garden.
First take a long look at your gardens and make notes on successes, disappointments, gaps, and changes that you’d like to make. Assess the ecosystem you have created and think about how you can make it even more supportive of our precious wildlife, beneficial insects, pollinators, and soil life. This is a great time to make lists of perennials to be moved, removed, and desired replacements.
A certain amount of garden clean-up is very important for reducing diseases and pests that are difficult to control. If you haven’t already done so, do remove diseased plants from your vegetable garden. You should have been removing diseased foliage and using organic controls for fungal diseases like mildew, blackspot, or rust before now, but if their disease-carrying foliage is falling now, keep them picked up and dispose of them responsibly.
Phlomis russelliana (Jerusalem Sage) in snow
But don’t be too quick to scalp those perennials and annuals! Many provide natural food and shelter sources that wildlife and beneficial insects depend on for winter survival. You may not have noticed, but so many beneficial insects and butterfly larvae spend the winter in the (often hollow) dead stems. If you throw them out, you’ll lose most of the beneficials that would otherwise keep the balance next year. Always keep an eye out for egg cases attached to stalks when you prune or clean up. There’s often an aesthetic side-benefit – many seed-heads look fabulous either crowned with snow or silhouetted against the snow-covered ground.
Some perennials die back to below ground (peonies, false indigo, gas plant, golden banner, balloon flower, desert four o’clock, gayfeather, leadwort/plumbago, etc.) leaving no basal growth and leaving a completely blank space. To make sure you don’t forget where they are and accidentally dig them up or step on them, leave dry stems until the new growth begins to appear in spring.
Little Bluestem in late autumn light
Unless you have an ‘ornamental’ grass that self-sows aggressively, leave grasses and their seedheads standing. If they are ‘cool-season’ grasses, you’ll want to leave them until about mid-February, then cut them to 3” above the ground so they can begin making unimpeded new growth as soon as the soil thaws. Dormant ‘warm-season’ grasses can remain attractive until warm weather comes and don’t need to be cut down until April.
Leaving dry stalks standing in the winter also helps preserve soil structure. Snow collects between the stalks and provides protection from freezing temperatures by insulation for the crowns of the plants, especially important for marginally hardy plants. Captured snow keeps soil temperature more consistent, protecting from extreme temperature fluctuations, and helps prevent the alternate freezing and thawing that can disrupt mycorrhizal networks (and uproot plants, especially new and small ones).
Leave the leaves! The larvae of many butterflies overwinter in the blanket of autumn leaves, as well as other beneficials. The leaves also provide cover for frogs, toads, and spiders. Songbirds eat more than just seeds; they search in the leaf litter for insect eggs and caterpillars. As leaves naturally break down over time, they feed the soil microbes that make nutrients available to plants. Worried about harboring snail and slugs? Before those leaves begin to fall, spread a non-toxic slug bait like Sluggo in areas of concern. You may want to remove leaves and twigs from patios, decks, walkways, and lawns, and that’s fine – especially if you can spread them under shrubs or pile them in a corner where they’ll remain undisturbed through the winter. And very large, flat leaves from trees like Catalpa, Basswood (Tilia americana), Norway Maple, Sycamore/London Planetree) should be cleared from beds or they can form a slick solid mat that smothers the crowns of smaller plants.
WINTER WATERING
Through the fall and winter, pay attention to the amount of precipitation your garden receives. In our often dry and windy winters, new plantings, fruit trees, evergreens, and roses are especially vulnerable, and are more likely to suffer or die from dehydration than from cold. New fall plantings will establish well with thorough watering every 2 weeks.
Mahonia repens winter color
Evergreens continue to transpire (give off water) during the winter because they have leaves or needles. If these plants cannot take up water, they will dehydrate and suffer, not showing injury until it’s too late. And roses, with their green-skinned canes, are far more likely to perish in winter from dehydration than from cold temperatures.
In the coming months if the ground isn’t frozen and the temperature is above 40 degrees Fahrenheit, give your garden a thorough watering when there’s been less than 2″ of natural precipitation in the previous 4 weeks. Water in late morning or early afternoon so that the water has time to sink in before it freezes. TIP: Use the auto populate feature on your electronic calendar to prompt you to winter-water!