Carol O'Meara, Colorado State University Extension

Carol O’Meara, Colorado State University Extension

The abrupt end to the garden season came with an unseasonable chill, smashing record lows and tying for largest temperature drop in one October day every recorded. Plants that normally shrug off a light frost are struggling to find new life, while the tender plants were killed outright.

While the sight of the dead are appealing the closer we get to Halloween, we can’t leave those carcasses out there forever. Disease and insects find a nice home amongst the wreckage and for a garden to remain healthy, fall cleanup begins in earnest. So put on your gloves and take advantage of the warmer spell were under now to get that garden tidied up for bed.

Before you start ripping out all of the downed material, stop, stretch and warm up for the tasks at hand. Not just to prepare your body, but also to take stock of what stays and what goes. Leaving some standing debris makes the garden interesting in winter, and beneficial insects can tuck themselves in for a cozy place to stay during the quiet season.

The biggest advantage for leaving plants standing into winter is the nesting sites they provide for overwintering pollinators. Many solitary bees use hollow stems to lay eggs, and leaving stems standing is a good way to help pollinators throughout the winter.

Hedge your bets by cutting some perennials back after they die to the ground but leave seed heads empty of their progeny, ornamental grasses with plumes, and flowers freeze-dried in the storm until late winter for texture and food for birds. But if you do this, leave only healthy plants standing; if they’re diseased, remove them and throw them out.

Leaving your plant clean up until spring allows the plant to capture more snow, funneling moisture to the soil. Snow, along with mulch, gathered at the base of plants sitting close to each other in a winter garden also gives them some added protection from wind. After the ground freezes, apply mulch to stabilize soil temperature and prevent alternate freezing and thawing of soil, which can lift crowns above soil levels.

Leaves, stalks, and rotting fruit are not as desirable; they should be cleaned up and placed in a compost pile. Weeds should be pulled and composted also, but clip and dispose of seed heads before you toss the plant on the pile. Typically, backyard compost piles don’t get hot enough to kill the seeds.

The same goes for plant material that’s diseased – dispose of them differently from composting because the pile won’t get hot enough to kill the disease organisms. If you have curbside composting offered by your waste haulers, putting these items into the bin is fine; commercial composting heats up enough to take care of the seeds and disease.

If you’re new to gardening and want to learn how to compost, check out one of the Backyard Composting classes offered by Boulder County Resource Conservation and our own CSU Colorado Master Gardeners:

• Monday, October 21, 6 p.m. to 8 p.m. at the Boulder County Recycling Center (1901 63rd St., Boulder)
• Monday, October 28, 6 p.m. to 8 p.m. at the Erie Community Center (450 Powers St., Erie).
• Saturday, November 2, 10:30 a.m. to 12:30 p.m. at the Louisville Public Library, First Floor Meeting Room (951 Spruce St., Louisville).

Classes are free but registration is required; sign up at

By Carol A. O’Meara. Carol is an Extension Agent – Horticulture Entomology at Colorado State University Extension Boulder County. For more information contact CSU Extension at the Boulder County Fairgrounds, 9595 Nelson Road, Box B, Longmont, 303.678.6377, e-mail [email protected] or visit