The landscape may be fading to auburn and gold as fall sets in, but gardeners can’t shake their green thumbs.
Here are some fall chores to consider, courtesy of Sarah Browning, University of Nebraska-Lincoln Extension educator in Lancaster County.
Cut irises to about 5 or 6 inches. This will reduce the threat of iris borer infestations, which overwinter in the leaves. If you leave about 5 inches of greenery, you’re sure to defeat the borer but still give the plant enough of the blade to draw food and collect leaves.
Do not cut these back. The foliage on perennial mums collects vegetation that serve as a mulch and holds in snow, which helps the plant survive. Cut the stems back in the spring. Keep it trimmed to about a foot tall until July 4, and then let it grow to its full height.
After greenery starts to turn brown, cut it to near the ground. Wait for it to turn brown, though, so that the roots can get as much nourishment as possible before winter.
Taller spirea, forsythia, lilac and other spring flowering shrubs
Do not cut these back or you’ll lose your spring blossoms. These shrubs set blooms on the past year’s growth.
Cut back to the ground simply to tidy up your yard and have that chore out of the way before spring. Hostas do not suffer from the same infestations as irises, so there’s no practical need to clear away the foliage.
Let the plant get nipped by a frost and then dig up the rhyzomes and bring them indoors for the winter.
Calla lilies, gladiolas, dahlias, caladiums
Dig up and bring in for the winter.
Ornamental grasses, tall sedums, Coneflower, brown-eyed Susans, etc.
Let these remain standing to add visual interest to your winter landscape and provide seeds for birds.
Shrub roses, knockout and carefree buck roses
Leave standing. Most shrub roses are winter hardy.
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More gardening tips
• Shrubby spirea: Cut these down to the crown every couple of years to get rid of the twigs and general clutter in the bush.
• Hybrid tea roses: If you’re planning to put a rose cone on the plant, cut the root low enough so the cone will go over it. If you’re going to mulch with compost, cut the canes to about 12-18 inches tall and mulch about 6-8 inches deep.
• Weeds: Now is a good time to eliminate weeds from your flower beds so that you’ve gotten a jump on spring. Spray your flower beds with herbicide to control perennial weeds, such as dandelions and ground ivy.
As long as the weeds are green, you can kill them. Be careful that you only spray the herbicide on days when the wind is blowing at less than 5 mph and be sure to spot spray only on the weed leaves, otherwise you’ll kill your plants. Look for herbicides that have two or more of the following in the active ingredients: dicamba, 2-4-D, Triclopyr, Quinclorac. Daytime air temperatures need to be above 40 degrees.
• Mulch: An aesthetic layer of two to three inches can be applied now. Wait until late November or so to apply a winter layer of mulch, about 6 inches deep. The purpose of mulch at that point is to avoid temperature fluctuations by keeping the soil cold.
• Dividing and planting of perennials: Finish this task by mid-October so your newly planted perennials have time to establish a root system and don’t get heaved out of the soil by a freeze-thaw cycle. Some flowers ideal for dividing include irises, day lilies, coneflower and hostas. Wait until spring to divide peonies.
• Watering: Keep watering until the ground freezes. Trees and shrubs need a deeper watering than lawns.
• Pruning: Wait until your trees have gone dormant and dropped their leaves before pruning. Wait until February or March to prune fruit trees.
• Grass seed: A few days remain to plant Kentucky blue grass, but it’s too late for tall fescue.